diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
new file mode 100644
index 0000000..ea9cf19
--- /dev/null
+++ b/.github/workflows/go.yml
@@ -0,0 +1,24 @@
+name: Go
+
+on:
+  push:
+    branches: [ master main ]
+  pull_request:
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.18
+
+    - name: Build
+      run: go build -v ./...
+
+    - name: Test
+      run: go test -v ./...
diff --git a/.github/workflows/golangci-lint.yml b/.github/workflows/golangci-lint.yml
new file mode 100644
index 0000000..44f2f1c
--- /dev/null
+++ b/.github/workflows/golangci-lint.yml
@@ -0,0 +1,44 @@
+name: golangci-lint
+on:
+  push:
+    tags:
+      - v*
+    branches:
+      - master
+      - main
+  pull_request:
+permissions:
+  contents: read
+  # Optional: allow read access to pull request. Use with `only-new-issues` option.
+  # pull-requests: read
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/setup-go@v3
+      - uses: actions/checkout@v3
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          # Optional: version of golangci-lint to use in form of v1.2 or v1.2.3 or `latest` to use the latest version
+          version: latest 
+
+          # Optional: working directory, useful for monorepos
+          # working-directory: somedir
+
+          # Optional: golangci-lint command line arguments.
+          # args: --issues-exit-code=0
+
+          # Optional: show only new issues if it's a pull request. The default value is `false`.
+          # only-new-issues: true
+
+          # Optional: if set to true then the all caching functionality will be complete disabled,
+          #           takes precedence over all other caching options.
+          # skip-cache: true
+
+          # Optional: if set to true then the action don't cache or restore ~/go/pkg.
+          # skip-pkg-cache: true
+
+          # Optional: if set to true then the action don't cache or restore ~/.cache/go-build.
+          # skip-build-cache: true
diff --git a/.gitignore b/.gitignore
index 5cc3fec..e009763 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,3 +27,4 @@ gin-bin
 bin
 config.yaml
 .idea
+.vscode
diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..8e6c9ce
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,89 @@
+run:
+  modules-download-mode: readonly
+  issues-exit-code: 0
+
+linters-settings:
+  exhaustive:
+    default-signifies-exhaustive: false
+  gci:
+    sections:
+      - standard
+      - default
+      - prefix(github.com/messagebird/sachet)
+  goconst:
+    min-occurrences: 5
+    ignore-tests: true
+  godot:
+    scope: toplevel
+    exclude:
+      - go-sumtype:decl
+      - check interfaces
+    capital: true
+  godox:
+    keywords:
+      - BUG
+      - FIXME
+      - HACK
+  goimports:
+    local-prefixes: github.com/messagebird/sachet
+  gosimple:
+    go: "1.18"
+    checks: ["all"]
+  lll:
+    line-length: 130
+    tab-width: 4
+  nolintlint:
+    allow-unused: false
+    allow-leading-space: false
+    allow-no-explanation: []
+    require-explanation: true
+    require-specific: true
+  staticcheck:
+    go: "1.18"
+    checks: ["all"]
+  stylecheck:
+    go: "1.18"
+    checks: ["all"]
+    dot-import-whitelist: []
+    initialisms: []
+    http-status-code-whitelist: []
+  unparam:
+    check-exported: true
+  unused:
+    go: "1.18"
+  whitespace:
+    multi-if: false
+    multi-func: false
+  tagliatelle:
+
+linters:
+  enable-all: true
+  disable:
+    # TODO: enable one by one
+    - ireturn
+    - forbidigo
+    - containedctx
+    - tagliatelle
+    - cyclop
+    - errcheck
+    - exhaustivestruct
+    - forcetypeassert
+    - funlen
+    - gochecknoglobals
+    - gochecknoinits
+    - goerr113
+    - gomnd
+    - gosec
+    - revive
+    - varnamelen
+    - wrapcheck
+    - noctx
+    - staticcheck
+    - stylecheck
+    - golint      
+    - interfacer 
+    - maligned    
+    - nlreturn    
+    - scopelint   
+    - testpackage 
+    - wsl
diff --git a/Dockerfile b/Dockerfile
index 667b4a7..05c6305 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.17 AS builder
+FROM golang:1.18 AS builder
 
 WORKDIR /build
 
@@ -6,7 +6,7 @@ COPY . .
 
 RUN GO111MODULE=on CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -mod vendor -o sachet github.com/messagebird/sachet/cmd/sachet
 
-FROM alpine
+FROM alpine:3.15
 
 COPY --from=builder /build/sachet /usr/local/bin
 COPY --chown=nobody examples/config.yaml /etc/sachet/config.yaml
diff --git a/README.md b/README.md
index 3d3a6d6..ea675ca 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,5 @@
 # Sachet
 
-[![Build Status](https://travis-ci.org/messagebird/sachet.svg?branch=master)](https://travis-ci.org/messagebird/sachet)
-
 Sachet (or सचेत) is Hindi for conscious. Sachet is an SMS alerting tool for the [Prometheus Alertmanager](https://github.com/prometheus/alertmanager).
 
 ## The problem
diff --git a/cmd/sachet/config.go b/cmd/sachet/config.go
index 258331a..747702a 100644
--- a/cmd/sachet/config.go
+++ b/cmd/sachet/config.go
@@ -3,11 +3,13 @@ package main
 import (
 	"io/ioutil"
 
-	"github.com/messagebird/sachet/provider/esendex"
+	"github.com/prometheus/alertmanager/template"
+	"gopkg.in/yaml.v2"
 
 	"github.com/messagebird/sachet/provider/aliyun"
 	"github.com/messagebird/sachet/provider/aspsms"
 	"github.com/messagebird/sachet/provider/cm"
+	"github.com/messagebird/sachet/provider/esendex"
 	"github.com/messagebird/sachet/provider/exotel"
 	"github.com/messagebird/sachet/provider/freemobile"
 	"github.com/messagebird/sachet/provider/ghasedak"
@@ -32,9 +34,6 @@ import (
 	"github.com/messagebird/sachet/provider/textmagic"
 	"github.com/messagebird/sachet/provider/turbosms"
 	"github.com/messagebird/sachet/provider/twilio"
-
-	"github.com/prometheus/alertmanager/template"
-	"gopkg.in/yaml.v2"
 )
 
 type ReceiverConf struct {
diff --git a/cmd/sachet/handlers.go b/cmd/sachet/handlers.go
new file mode 100644
index 0000000..cafe170
--- /dev/null
+++ b/cmd/sachet/handlers.go
@@ -0,0 +1,110 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"sort"
+	"strings"
+
+	"github.com/prometheus/alertmanager/template"
+
+	"github.com/messagebird/sachet"
+)
+
+type handlers struct{}
+
+func newAlertText(data template.Data) string {
+	if len(data.Alerts) > 1 {
+		labelAlerts := map[string]template.Alerts{
+			"Firing":   data.Alerts.Firing(),
+			"Resolved": data.Alerts.Resolved(),
+		}
+		text := ""
+		for label, alerts := range labelAlerts {
+			if len(alerts) > 0 {
+				text += label + ": \n"
+				for _, alert := range alerts {
+					text += alert.Labels["alertname"] + " @" + alert.Labels["instance"]
+					if len(alert.Labels["exported_instance"]) > 0 {
+						text += " (" + alert.Labels["exported_instance"] + ")"
+					}
+					text += "\n"
+				}
+			}
+		}
+		return text
+	}
+
+	if len(data.Alerts) == 1 {
+		alert := data.Alerts[0]
+		tuples := []string{}
+		for k, v := range alert.Labels {
+			tuples = append(tuples, k+"= "+v)
+		}
+		sort.Strings(tuples)
+		return strings.ToUpper(data.Status) + " \n" + strings.Join(tuples, "\n")
+	}
+
+	return "Alert \n" + strings.Join(data.CommonLabels.Values(), " | ")
+}
+
+func (h handlers) Alert(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	// https://godoc.org/github.com/prometheus/alertmanager/template#Data
+	data := template.Data{}
+	if err := json.NewDecoder(r.Body).Decode(&data); err != nil {
+		errorHandler(w, http.StatusBadRequest, err, "?")
+		return
+	}
+
+	receiverConf := receiverConfByReceiver(data.Receiver)
+	if receiverConf == nil {
+		errorHandler(w, http.StatusBadRequest, fmt.Errorf("Receiver missing: %s", data.Receiver), "?")
+		return
+	}
+	provider, err := providerByName(receiverConf.Provider)
+	if err != nil {
+		errorHandler(w, http.StatusInternalServerError, err, receiverConf.Provider)
+		return
+	}
+
+	var text string
+	if receiverConf.Text != "" {
+		text, err = tmpl.ExecuteTextString(receiverConf.Text, data)
+		if err != nil {
+			errorHandler(w, http.StatusInternalServerError, err, receiverConf.Provider)
+			return
+		}
+	} else {
+		text = newAlertText(data)
+	}
+
+	message := sachet.Message{
+		To:   receiverConf.To,
+		From: receiverConf.From,
+		Type: receiverConf.Type,
+		Text: text,
+	}
+
+	if err = provider.Send(message); err != nil {
+		errorHandler(w, http.StatusBadRequest, err, receiverConf.Provider)
+		return
+	}
+
+	requestTotal.WithLabelValues("200", receiverConf.Provider).Inc()
+}
+
+func (h handlers) Reload(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+	if r.Method == http.MethodPost {
+		log.Println("Loading configuration file", *configFile)
+		if err := LoadConfig(*configFile); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+	} else {
+		http.Error(w, "Invalid request method.", http.StatusMethodNotAllowed)
+	}
+}
diff --git a/cmd/sachet/handlers_test.go b/cmd/sachet/handlers_test.go
new file mode 100644
index 0000000..5fe3dfd
--- /dev/null
+++ b/cmd/sachet/handlers_test.go
@@ -0,0 +1,62 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/prometheus/alertmanager/template"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_newAlertText(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		name string
+		data template.Data
+		exp  string
+	}{
+		{
+			name: "empty",
+			data: template.Data{},
+			exp:  "Alert \n",
+		},
+		{
+			name: "empty alerts",
+			data: template.Data{
+				Alerts: template.Alerts{
+					template.Alert{},
+				},
+			},
+			exp: " \n",
+		},
+		{
+			name: "alert labels",
+			data: template.Data{
+				Alerts: template.Alerts{
+					template.Alert{
+						Labels: map[string]string{
+							"alertname":         "a",
+							"instance":          "a",
+							"exported_instance": "a",
+						},
+					},
+				},
+			},
+			exp: " \nalertname= a\nexported_instance= a\ninstance= a",
+		},
+		{
+			name: "common labels",
+			data: template.Data{
+				CommonLabels: template.KV{
+					"a": "a",
+					"b": "b",
+					"c": "c",
+				},
+			},
+			exp: "Alert \na | b | c",
+		},
+	}
+	for _, tc := range cases {
+		assert.Equal(t, tc.exp, newAlertText(tc.data), tc.name)
+	}
+}
diff --git a/cmd/sachet/main.go b/cmd/sachet/main.go
index 0a2856f..60d9b9f 100644
--- a/cmd/sachet/main.go
+++ b/cmd/sachet/main.go
@@ -8,16 +8,16 @@ import (
 	"net/http"
 	"os"
 	"strconv"
-	"strings"
 
-	"github.com/messagebird/sachet/provider/esendex"
-
-	"github.com/messagebird/sachet/provider/tencentcloud"
+	"github.com/heptiolabs/healthcheck"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 
 	"github.com/messagebird/sachet"
 	"github.com/messagebird/sachet/provider/aliyun"
 	"github.com/messagebird/sachet/provider/aspsms"
 	"github.com/messagebird/sachet/provider/cm"
+	"github.com/messagebird/sachet/provider/esendex"
 	"github.com/messagebird/sachet/provider/exotel"
 	"github.com/messagebird/sachet/provider/freemobile"
 	"github.com/messagebird/sachet/provider/ghasedak"
@@ -38,15 +38,10 @@ import (
 	"github.com/messagebird/sachet/provider/sms77"
 	"github.com/messagebird/sachet/provider/smsc"
 	"github.com/messagebird/sachet/provider/telegram"
+	"github.com/messagebird/sachet/provider/tencentcloud"
 	"github.com/messagebird/sachet/provider/textmagic"
 	"github.com/messagebird/sachet/provider/turbosms"
 	"github.com/messagebird/sachet/provider/twilio"
-
-	"github.com/prometheus/alertmanager/template"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
-
-	"github.com/heptiolabs/healthcheck"
 )
 
 var (
@@ -62,92 +57,11 @@ func main() {
 		log.Fatalf("Error loading configuration: %s", err)
 	}
 
-	http.HandleFunc("/alert", func(w http.ResponseWriter, r *http.Request) {
-		defer r.Body.Close()
-
-		// https://godoc.org/github.com/prometheus/alertmanager/template#Data
-		data := template.Data{}
-		if err := json.NewDecoder(r.Body).Decode(&data); err != nil {
-			errorHandler(w, http.StatusBadRequest, err, "?")
-			return
-		}
-
-		receiverConf := receiverConfByReceiver(data.Receiver)
-		if receiverConf == nil {
-			errorHandler(w, http.StatusBadRequest, fmt.Errorf("Receiver missing: %s", data.Receiver), "?")
-			return
-		}
-		provider, err := providerByName(receiverConf.Provider)
-		if err != nil {
-			errorHandler(w, http.StatusInternalServerError, err, receiverConf.Provider)
-			return
-		}
-
-		var text string
-		if receiverConf.Text != "" {
-			text, err = tmpl.ExecuteTextString(receiverConf.Text, data)
-			if err != nil {
-				errorHandler(w, http.StatusInternalServerError, err, receiverConf.Provider)
-				return
-			}
-		} else {
-			if len(data.Alerts) > 1 {
-				labelAlerts := map[string]template.Alerts{
-					"Firing":   data.Alerts.Firing(),
-					"Resolved": data.Alerts.Resolved(),
-				}
-				for label, alerts := range labelAlerts {
-					if len(alerts) > 0 {
-						text += label + ": \n"
-						for _, alert := range alerts {
-							text += alert.Labels["alertname"] + " @" + alert.Labels["instance"]
-							if len(alert.Labels["exported_instance"]) > 0 {
-								text += " (" + alert.Labels["exported_instance"] + ")"
-							}
-							text += "\n"
-						}
-					}
-				}
-			} else if len(data.Alerts) == 1 {
-				alert := data.Alerts[0]
-				tuples := []string{}
-				for k, v := range alert.Labels {
-					tuples = append(tuples, k+"= "+v)
-				}
-				text = strings.ToUpper(data.Status) + " \n" + strings.Join(tuples, "\n")
-			} else {
-				text = "Alert \n" + strings.Join(data.CommonLabels.Values(), " | ")
-			}
-		}
-
-		message := sachet.Message{
-			To:   receiverConf.To,
-			From: receiverConf.From,
-			Type: receiverConf.Type,
-			Text: text,
-		}
-
-		if err = provider.Send(message); err != nil {
-			errorHandler(w, http.StatusBadRequest, err, receiverConf.Provider)
-			return
-		}
-
-		requestTotal.WithLabelValues("200", receiverConf.Provider).Inc()
-	})
+	app := handlers{}
 
+	http.HandleFunc("/alert", app.Alert)
 	http.Handle("/metrics", promhttp.Handler())
-
-	http.HandleFunc("/-/reload", func(w http.ResponseWriter, r *http.Request) {
-		defer r.Body.Close()
-		if r.Method == "POST" {
-			log.Println("Loading configuration file", *configFile)
-			if err := LoadConfig(*configFile); err != nil {
-				http.Error(w, err.Error(), http.StatusInternalServerError)
-			}
-		} else {
-			http.Error(w, "Invalid request method.", http.StatusMethodNotAllowed)
-		}
-	})
+	http.HandleFunc("/-/reload", app.Reload)
 
 	hc := healthcheck.NewMetricsHandler(prometheus.DefaultRegisterer, "sachet")
 
@@ -163,7 +77,7 @@ func main() {
 	log.Fatal(http.ListenAndServe(*listenAddress, nil))
 }
 
-// receiverConfByReceiver loops the receiver conf list and returns the first instance with that name
+// receiverConfByReceiver loops the receiver conf list and returns the first instance with that name.
 func receiverConfByReceiver(name string) *ReceiverConf {
 	for i := range config.Receivers {
 		rc := &config.Receivers[i]
@@ -175,6 +89,7 @@ func receiverConfByReceiver(name string) *ReceiverConf {
 }
 
 func providerByName(name string) (sachet.Provider, error) {
+	// TODO: use map of providers instead
 	switch name {
 	case "messagebird":
 		return messagebird.NewMessageBird(config.Providers.MessageBird), nil
@@ -219,7 +134,7 @@ func providerByName(name string) (sachet.Provider, error) {
 	case "ovh":
 		return ovh.NewOvh(config.Providers.OVH)
 	case "tencentcloud":
-		return tencentcloud.NewTencentCloud(config.Providers.TencentCloud)
+		return tencentcloud.NewTencentCloud(config.Providers.TencentCloud), nil
 	case "sap":
 		return sap.NewSap(config.Providers.Sap), nil
 	case "esendex":
@@ -250,10 +165,15 @@ func errorHandler(w http.ResponseWriter, status int, err error, provider string)
 		err.Error(),
 	}
 	// respond json
-	bytes, _ := json.Marshal(data)
-	json := string(bytes[:])
-	fmt.Fprint(w, json)
+	body, err := json.Marshal(data)
+	if err != nil {
+		log.Fatalf("marshalling error: " + err.Error())
+	}
+
+	if _, err := w.Write(body); err != nil {
+		log.Fatalf("marshalling error: " + err.Error())
+	}
 
-	log.Println("Error: " + json)
+	log.Println("error: " + string(body))
 	requestTotal.WithLabelValues(strconv.FormatInt(int64(status), 10), provider).Inc()
 }
diff --git a/cmd/sachet/main_test.go b/cmd/sachet/main_test.go
index e144f63..0c7a388 100644
--- a/cmd/sachet/main_test.go
+++ b/cmd/sachet/main_test.go
@@ -1,6 +1,22 @@
 package main
 
-import "testing"
+import (
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
 
-func TestPlaceholder(t *testing.T) {
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_errorHandler(t *testing.T) {
+	t.Parallel()
+
+	var (
+		w      = httptest.NewRecorder()
+		expect = `{"Error":true,"Status":403,"Message":"access forbidden"}`
+		err    = errors.New("access forbidden")
+	)
+	errorHandler(w, http.StatusForbidden, err, "test")
+	assert.Equal(t, expect, w.Body.String())
 }
diff --git a/cmd/sachet/telemetry.go b/cmd/sachet/telemetry.go
index 77ca46f..ebc303c 100644
--- a/cmd/sachet/telemetry.go
+++ b/cmd/sachet/telemetry.go
@@ -2,14 +2,12 @@ package main
 
 import "github.com/prometheus/client_golang/prometheus"
 
-var (
-	requestTotal = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "sachet_requests_total",
-			Help: "How many requests processed, partitioned by status code and provider.",
-		},
-		[]string{"code", "provider"},
-	)
+var requestTotal = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "sachet_requests_total",
+		Help: "How many requests processed, partitioned by status code and provider.",
+	},
+	[]string{"code", "provider"},
 )
 
 func init() {
diff --git a/provider/aliyun/aliyun.go b/provider/aliyun/aliyun.go
index d66bbb2..34a8d67 100644
--- a/provider/aliyun/aliyun.go
+++ b/provider/aliyun/aliyun.go
@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/aliyun/alibaba-cloud-sdk-go/services/dysmsapi"
+
 	"github.com/messagebird/sachet"
 )
 
@@ -19,6 +20,8 @@ type Config struct {
 	TemplateParamKey string `yaml:"template_param_key"`
 }
 
+var _ (sachet.Provider) = (*Aliyun)(nil)
+
 type Aliyun struct {
 	client *dysmsapi.Client
 	config *Config
@@ -36,7 +39,6 @@ func NewAliyun(config Config) (*Aliyun, error) {
 }
 
 func (aliyun *Aliyun) Send(message sachet.Message) error {
-	var err error = nil
 	switch message.Type {
 	case "", "text":
 		request := dysmsapi.CreateSendSmsRequest()
@@ -52,11 +54,12 @@ func (aliyun *Aliyun) Send(message sachet.Message) error {
 			var response *dysmsapi.SendSmsResponse
 			response, err = aliyun.client.SendSms(request)
 			if err == nil && (!response.IsSuccess() || response.Code != "OK") {
-				err = fmt.Errorf(response.String())
+				return fmt.Errorf(response.String())
 			}
 		}
 	default:
 		return fmt.Errorf("unknown message type %s", message.Type)
 	}
-	return err
+
+	return nil
 }
diff --git a/provider/aspsms/aspsms.go b/provider/aspsms/aspsms.go
index 8fafed7..e91805a 100644
--- a/provider/aspsms/aspsms.go
+++ b/provider/aspsms/aspsms.go
@@ -11,20 +11,22 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-// Config is the configuration struct for AspSms provider
+// Config is the configuration struct for AspSms provider.
 type Config struct {
 	Username string `yaml:"username"`
 	Password string `yaml:"password"`
 }
 
-// AspSms contains the necessary values for the AspSms provider
+var _ (sachet.Provider) = (*AspSms)(nil)
+
+// AspSms contains the necessary values for the AspSms provider.
 type AspSms struct {
 	Config
 
 	httpClient *http.Client
 }
 
-// NewAspSms creates and returns a new AspSms struct
+// NewAspSms creates and returns a new AspSms struct.
 func NewAspSms(config Config) *AspSms {
 	return &AspSms{
 		config,
@@ -42,7 +44,7 @@ type requestPayload struct {
 
 const apiUrl = "https://json.aspsms.com/SendSimpleTextSMS"
 
-// Send sends SMS to user registered in configuration
+// Send sends SMS to user registered in configuration.
 func (c *AspSms) Send(message sachet.Message) error {
 	params := requestPayload{
 		Username:    c.Username,
diff --git a/provider/cm/cm.go b/provider/cm/cm.go
index 92c3f61..f1c6604 100644
--- a/provider/cm/cm.go
+++ b/provider/cm/cm.go
@@ -10,19 +10,21 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-// Config is the configuration struct for CM provider
+// Config is the configuration struct for CM provider.
 type Config struct {
 	ProductToken string `yaml:"producttoken"`
 }
 
-// CM contains the necessary values for the CM provider
+var _ (sachet.Provider) = (*CM)(nil)
+
+// CM contains the necessary values for the CM provider.
 type CM struct {
 	Config
 }
 
 var cmHTTPClient = &http.Client{Timeout: time.Second * 20}
 
-// NewCM creates and returns a new CM struct
+// NewCM creates and returns a new CM struct.
 func NewCM(config Config) *CM {
 	return &CM{config}
 }
@@ -48,7 +50,7 @@ type CMPayload struct {
 	} `json:"messages"`
 }
 
-// Send sends SMS to n number of people using Bulk SMS API
+// Send sends SMS to n number of people using Bulk SMS API.
 func (c *CM) Send(message sachet.Message) error {
 	smsURL := "https://gw.cmtelecom.com/v1.0/message"
 
@@ -87,7 +89,10 @@ func (c *CM) Send(message sachet.Message) error {
 	defer response.Body.Close()
 
 	var body []byte
-	response.Body.Read(body)
+	_, err = response.Body.Read(body)
+	if err != nil {
+		return err
+	}
 	if response.StatusCode == http.StatusOK && err == nil {
 		return nil
 	}
diff --git a/provider/esendex/esendex.go b/provider/esendex/esendex.go
index 061ee2a..dfaf484 100644
--- a/provider/esendex/esendex.go
+++ b/provider/esendex/esendex.go
@@ -6,10 +6,11 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"github.com/messagebird/sachet"
 	"io/ioutil"
 	"net/http"
 	"time"
+
+	"github.com/messagebird/sachet"
 )
 
 const (
@@ -23,6 +24,8 @@ type Config struct {
 	AccountReference string `yaml:"account_reference"`
 }
 
+var _ (sachet.Provider) = (*Esendex)(nil)
+
 type Esendex struct {
 	Config
 	httpClient *http.Client
@@ -40,7 +43,7 @@ func (e *Esendex) Send(message sachet.Message) (err error) {
 		err = e.sendOne(message, phoneNumber)
 
 		if err != nil {
-			return fmt.Errorf("failed to make API call to Esendex: %s", err)
+			return fmt.Errorf("failed to make API call to Esendex: %w", err)
 		}
 	}
 
@@ -81,7 +84,6 @@ func (e *Esendex) sendOne(message sachet.Message, phoneNumber string) (err error
 	}
 
 	data, err := json.Marshal(params)
-
 	if err != nil {
 		return err
 	}
@@ -98,7 +100,6 @@ func (e *Esendex) sendOne(message sachet.Message, phoneNumber string) (err error
 	request.SetBasicAuth(e.Config.User, e.Config.ApiToken)
 
 	response, err := e.httpClient.Do(request)
-
 	if err != nil {
 		return err
 	}
diff --git a/provider/exotel/exotel.go b/provider/exotel/exotel.go
index ea782f1..bd0aed5 100644
--- a/provider/exotel/exotel.go
+++ b/provider/exotel/exotel.go
@@ -10,28 +10,30 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-//Config configuration struct for exotel Client
+// Config configuration struct for exotel Client.
 type Config struct {
 	AccountSID string `yaml:"account_sid"`
 	AuthToken  string `yaml:"auth_token"`
 }
 
-//ExotelRequestTimeout  is the timeout for http request to exotel
+// ExotelRequestTimeout  is the timeout for http request to exotel.
 const ExotelRequestTimeout = time.Second * 20
 
-//Exotel is the exte Exotel
+var _ (sachet.Provider) = (*Exotel)(nil)
+
+// Exotel is the exte Exotel.
 type Exotel struct {
 	AccountSid string
 	Token      string
 }
 
-//NewExotel creates a new
+// NewExotel creates a new.
 func NewExotel(config Config) *Exotel {
 	Exotel := &Exotel{AccountSid: config.AccountSID, Token: config.AuthToken}
 	return Exotel
 }
 
-//Send send sms to n number of people using bulk sms api
+// Send send sms to n number of people using bulk sms api.
 func (c *Exotel) Send(message sachet.Message) (err error) {
 	smsURL := fmt.Sprintf("https://twilix.exotel.in/v1/Accounts/%s/Sms/send.json", c.AccountSid)
 	var request *http.Request
@@ -39,7 +41,7 @@ func (c *Exotel) Send(message sachet.Message) (err error) {
 
 	form := url.Values{"From": {message.From}, "Body": {message.Text}, "To": message.To}
 
-	//preparing the request
+	// preparing the request.
 	request, err = http.NewRequest("POST", smsURL, strings.NewReader(form.Encode()))
 	if err != nil {
 		return
@@ -48,7 +50,8 @@ func (c *Exotel) Send(message sachet.Message) (err error) {
 	request.SetBasicAuth(c.AccountSid, c.Token)
 	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 	request.Header.Set("User-Agent", "SachetV1.0")
-	//calling the endpoint
+
+	// calling the endpoint.
 	httpClient := &http.Client{}
 	httpClient.Timeout = ExotelRequestTimeout
 
@@ -58,7 +61,10 @@ func (c *Exotel) Send(message sachet.Message) (err error) {
 	}
 	defer resp.Body.Close()
 	var body []byte
-	resp.Body.Read(body)
+	_, err = resp.Body.Read(body)
+	if err != nil {
+		return err
+	}
 	if resp.StatusCode == http.StatusOK && err == nil {
 		return
 	}
diff --git a/provider/freemobile/freemobile.go b/provider/freemobile/freemobile.go
index 41204f6..06f2791 100644
--- a/provider/freemobile/freemobile.go
+++ b/provider/freemobile/freemobile.go
@@ -10,21 +10,23 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-// Config is the configuration struct for FreeMobile provider
+// Config is the configuration struct for FreeMobile provider.
 type Config struct {
 	Username string `yaml:"username"`
 	Password string `yaml:"password"`
 	URL      string `yaml:"url"`
 }
 
-// FreeMobile contains the necessary values for the FreeMobile provider
+var _ (sachet.Provider) = (*FreeMobile)(nil)
+
+// FreeMobile contains the necessary values for the FreeMobile provider.
 type FreeMobile struct {
 	Config
 }
 
 var freemobileHTTPClient = &http.Client{Timeout: time.Second * 20}
 
-// NewFreeMobile creates and returns a new FreeMobile struct
+// NewFreeMobile creates and returns a new FreeMobile struct.
 func NewFreeMobile(config Config) *FreeMobile {
 	if config.URL == "" {
 		config.URL = "https://smsapi.free-mobile.fr/sendmsg"
@@ -38,7 +40,7 @@ type payload struct {
 	Message string `json:"msg"`
 }
 
-// Send sends SMS to user registered in configuration
+// Send sends SMS to user registered in configuration.
 func (c *FreeMobile) Send(message sachet.Message) error {
 	params := payload{
 		User:    c.Username,
@@ -62,6 +64,7 @@ func (c *FreeMobile) Send(message sachet.Message) error {
 	if err != nil {
 		return err
 	}
+	defer response.Body.Close()
 
 	if response.StatusCode == http.StatusOK && err == nil {
 		return nil
diff --git a/provider/ghasedak/ghasedak.go b/provider/ghasedak/ghasedak.go
index 717ee91..4898561 100644
--- a/provider/ghasedak/ghasedak.go
+++ b/provider/ghasedak/ghasedak.go
@@ -1,63 +1,65 @@
-package ghasedak
-
-import (
-	"fmt"
-	"io/ioutil"
-	"net/http"
-	"net/url"
-	"strings"
-	"time"
-
-	"github.com/messagebird/sachet"
-)
-
-// Retrieving required data from 'ghasedak' sections of config.yaml
-type Config struct {
-	APIToken string `yaml:"api_token"`
-}
-
-// Creating the KaveNegar to contain provider data
-type Ghasedak struct {
-	Config
-	HTTPClient *http.Client // The HTTP client to send requests on
-}
-
-// Ghasedak creates and returns a new Ghasedak struct
-func NewGhasedak(config Config) *Ghasedak {
-	return &Ghasedak{
-		config,
-		&http.Client{Timeout: time.Second * 20},
-	}
-}
-
-// Building the API and call the Ghasedak endpoint to send SMS to the configured receptor from config.yaml
-func (ns *Ghasedak) Send(message sachet.Message) error {
-	endpoint := "https://api.ghasedak.me/v2/sms/send/pair"
-	data := url.Values{}
-	data.Set("message", message.Text)
-	data.Set("receptor", strings.Join(message.To, ","))
-	request, err := http.NewRequest("POST", endpoint, strings.NewReader(data.Encode()))
-	if err != nil {
-		return err
-	}
-	request.Header.Set("User-Agent", "Sachet")
-	request.Header.Add("content-type", "application/x-www-form-urlencoded")
-	request.Header.Add("apikey", ns.APIToken)
-	request.Header.Add("cache-control", "no-cache")
-	response, err := ns.HTTPClient.Do(request)
-	if err != nil {
-		return err
-	}
-	defer response.Body.Close()
-
-	if response.StatusCode != http.StatusOK {
-		body, _ := ioutil.ReadAll(response.Body)
-		return fmt.Errorf(
-			"SMS sending failed. HTTP status code: %d, Response body: %s",
-			response.StatusCode,
-			body,
-		)
-	}
-	fmt.Println("Message sent: ", message.Text)
-	return nil
-}
+package ghasedak
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/messagebird/sachet"
+)
+
+// Retrieving required data from 'ghasedak' sections of config.yaml.
+type Config struct {
+	APIToken string `yaml:"api_token"`
+}
+
+var _ (sachet.Provider) = (*Ghasedak)(nil)
+
+// Creating the KaveNegar to contain provider data.
+type Ghasedak struct {
+	Config
+	HTTPClient *http.Client // The HTTP client to send requests on.
+}
+
+// Ghasedak creates and returns a new Ghasedak struct.
+func NewGhasedak(config Config) *Ghasedak {
+	return &Ghasedak{
+		config,
+		&http.Client{Timeout: time.Second * 20},
+	}
+}
+
+// Building the API and call the Ghasedak endpoint to send SMS to the configured receptor from config.yaml.
+func (ns *Ghasedak) Send(message sachet.Message) error {
+	endpoint := "https://api.ghasedak.me/v2/sms/send/pair"
+	data := url.Values{}
+	data.Set("message", message.Text)
+	data.Set("receptor", strings.Join(message.To, ","))
+	request, err := http.NewRequest("POST", endpoint, strings.NewReader(data.Encode()))
+	if err != nil {
+		return err
+	}
+	request.Header.Set("User-Agent", "Sachet")
+	request.Header.Add("content-type", "application/x-www-form-urlencoded")
+	request.Header.Add("apikey", ns.APIToken)
+	request.Header.Add("cache-control", "no-cache")
+	response, err := ns.HTTPClient.Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+
+	if response.StatusCode != http.StatusOK {
+		body, _ := ioutil.ReadAll(response.Body)
+		return fmt.Errorf(
+			"SMS sending failed. HTTP status code: %d, Response body: %s",
+			response.StatusCode,
+			body,
+		)
+	}
+	fmt.Println("Message sent: ", message.Text)
+	return nil
+}
diff --git a/provider/infobip/infobip.go b/provider/infobip/infobip.go
index 41afae1..ca4b05a 100644
--- a/provider/infobip/infobip.go
+++ b/provider/infobip/infobip.go
@@ -10,16 +10,18 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-//Config configuration struct for Infobip Client
+// Config configuration struct for Infobip Client.
 type Config struct {
 	Token  string `yaml:"token"`
 	Secret string `yaml:"secret"`
 }
 
-//InfobipRequestTimeout  is the timeout for http request to Infobip
+// InfobipRequestTimeout  is the timeout for http request to Infobip.
 const InfobipRequestTimeout = time.Second * 20
 
-//Infobip is the exte Infobip
+var _ (sachet.Provider) = (*Infobip)(nil)
+
+// Infobip is the exte Infobip.
 type Infobip struct {
 	Config
 }
@@ -38,16 +40,16 @@ type InfobipPayload struct {
 	Messages []InfobipMessage `json:"messages"`
 }
 
-//NewInfobip creates a new
+// NewInfobip creates a new.
 func NewInfobip(config Config) *Infobip {
 	Infobip := &Infobip{config}
 	return Infobip
 }
 
-//Send send sms to n number of people using bulk sms api
+// Send send sms to n number of people using bulk sms api.
 func (c *Infobip) Send(message sachet.Message) (err error) {
 	smsURL := "https://api.infobip.com/sms/2/text/advanced"
-	//smsURL = "http://requestb.in/pwf2ufpw"
+	// smsURL = "http://requestb.in/pwf2ufpw"
 	var request *http.Request
 	var resp *http.Response
 
@@ -70,7 +72,7 @@ func (c *Infobip) Send(message sachet.Message) (err error) {
 		return err
 	}
 
-	//preparing the request
+	// preparing the request.
 	request, err = http.NewRequest("POST", smsURL, bytes.NewBuffer(data))
 	if err != nil {
 		return
@@ -79,7 +81,7 @@ func (c *Infobip) Send(message sachet.Message) (err error) {
 	request.SetBasicAuth(c.Token, c.Secret)
 	request.Header.Set("Content-Type", "application/json")
 	request.Header.Set("User-Agent", "SachetV1.0")
-	//calling the endpoint
+	// calling the endpoint.
 	httpClient := &http.Client{}
 	httpClient.Timeout = InfobipRequestTimeout
 
@@ -89,7 +91,10 @@ func (c *Infobip) Send(message sachet.Message) (err error) {
 	}
 	defer resp.Body.Close()
 	var body []byte
-	resp.Body.Read(body)
+	_, err = resp.Body.Read(body)
+	if err != nil {
+		return
+	}
 	if resp.StatusCode == http.StatusOK && err == nil {
 		return
 	}
diff --git a/provider/kannel/kannel.go b/provider/kannel/kannel.go
index da98ff3..b633710 100644
--- a/provider/kannel/kannel.go
+++ b/provider/kannel/kannel.go
@@ -9,31 +9,39 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-//Config configuration struct for Kannel Client
+// Config configuration struct for Kannel Client.
 type Config struct {
 	URL  string `yaml:"url"`
 	User string `yaml:"username"`
 	Pass string `yaml:"password"`
 }
 
-//KannelRequestTimeout  is the timeout for http request to Kannel
+// KannelRequestTimeout  is the timeout for http request to Kannel.
 const KannelRequestTimeout = time.Second * 20
 
-//Kannel is the exte Kannel
+var _ (sachet.Provider) = (*Kannel)(nil)
+
+// Kannel is the exte Kannel.
 type Kannel struct {
 	Config
 }
 
-//NewKannel creates a new
+// NewKannel creates a new.
 func NewKannel(config Config) *Kannel {
 	Kannel := &Kannel{config}
 	return Kannel
 }
 
-//Send send sms to n number of people using bulk sms api
-func (c *Kannel) Send(message sachet.Message) (err error) {
+// Send send sms to n number of people using bulk sms api.
+func (c *Kannel) Send(message sachet.Message) error {
 	for _, recipient := range message.To {
-		queryParams := url.Values{"from": {message.From}, "to": {recipient}, "text": {message.Text}, "user": {c.User}, "pass": {c.Pass}}
+		queryParams := url.Values{
+			"from": {message.From},
+			"to":   {recipient},
+			"text": {message.Text},
+			"user": {c.User},
+			"pass": {c.Pass},
+		}
 
 		request, err := http.NewRequest("GET", c.URL, nil)
 		if err != nil {
@@ -52,10 +60,12 @@ func (c *Kannel) Send(message sachet.Message) (err error) {
 		if err != nil {
 			return err
 		}
+		defer response.Body.Close()
 
-		if response.StatusCode >= 400 {
+		if response.StatusCode >= http.StatusBadRequest {
 			return fmt.Errorf("Failed sending sms. statusCode: %d", response.StatusCode)
 		}
 	}
-	return
+
+	return nil
 }
diff --git a/provider/kavenegar/kavenegar.go b/provider/kavenegar/kavenegar.go
index 48289aa..8322623 100644
--- a/provider/kavenegar/kavenegar.go
+++ b/provider/kavenegar/kavenegar.go
@@ -10,19 +10,21 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-// Retrieving required data from 'kavenegar' sections of config.yaml
+// Retrieving required data from 'kavenegar' sections of config.yaml.
 type Config struct {
 	APIToken     string   `yaml:"api_token"`
 	PhoneNumbers []string `yaml:"phone_numbers"`
 }
 
-// Creating the KaveNegar to contain provider data
+var _ (sachet.Provider) = (*KaveNegar)(nil)
+
+// Creating the KaveNegar to contain provider data.
 type KaveNegar struct {
 	Config
-	HTTPClient *http.Client // The HTTP client to send requests on
+	HTTPClient *http.Client // The HTTP client to send requests on.
 }
 
-// KaveNegar creates and returns a new KaveNegar struct
+// KaveNegar creates and returns a new KaveNegar struct.
 func NewKaveNegar(config Config) *KaveNegar {
 	return &KaveNegar{
 		config,
@@ -30,7 +32,7 @@ func NewKaveNegar(config Config) *KaveNegar {
 	}
 }
 
-// Building the API and call the KaveNegar endpoint to send SMS to the configured receptor from config.yaml
+// Building the API and call the KaveNegar endpoint to send SMS to the configured receptor from config.yaml.
 func (ns *KaveNegar) Send(message sachet.Message) error {
 	url := "https://api.kavenegar.com/v1/" + ns.APIToken + "/sms/send.json"
 	request, err := http.NewRequest("GET", url, nil)
@@ -40,7 +42,8 @@ func (ns *KaveNegar) Send(message sachet.Message) error {
 	request.Header.Set("User-Agent", "Sachet")
 	params := request.URL.Query()
 	params.Add("receptor", strings.Join(message.To, ","))
-	// "params.Add("sender", message.From)" retrieves the sender number using "from" under receivers section, if you leave that empty, KaveNegar will use default sender SMS number to send the message
+	// "params.Add("sender", message.From)" retrieves the sender number using "from" under receivers section,
+	// if you leave that empty, KaveNegar will use default sender SMS number to send the message.
 	params.Add("sender", message.From)
 	params.Add("message", message.Text)
 	request.URL.RawQuery = params.Encode()
diff --git a/provider/mailruim/mailruim.go b/provider/mailruim/mailruim.go
index b4da8eb..5c4e463 100644
--- a/provider/mailruim/mailruim.go
+++ b/provider/mailruim/mailruim.go
@@ -2,6 +2,7 @@ package mailruim
 
 import (
 	botgolang "github.com/mail-ru-im/bot-golang"
+
 	"github.com/messagebird/sachet"
 )
 
@@ -10,6 +11,8 @@ type Config struct {
 	Url   string `yaml:"url"`
 }
 
+var _ (sachet.Provider) = (*MailruIM)(nil)
+
 type MailruIM struct {
 	bot *botgolang.Bot
 }
@@ -28,7 +31,9 @@ func NewMailruIM(config Config) (*MailruIM, error) {
 func (mr *MailruIM) Send(message sachet.Message) error {
 	for _, ChatID := range message.To {
 		msg := mr.bot.NewTextMessage(ChatID, message.Text)
-		msg.Send()
+		if err := msg.Send(); err != nil {
+			// TODO: handle the error
+		}
 	}
 	return nil
 }
diff --git a/provider/mediaburst/mediaburst.go b/provider/mediaburst/mediaburst.go
index 6c8ce53..771a63d 100644
--- a/provider/mediaburst/mediaburst.go
+++ b/provider/mediaburst/mediaburst.go
@@ -10,26 +10,28 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-//Config configuration struct for mediaburst Client
+// Config configuration struct for mediaburst Client.
 type Config struct {
 	APIKey string `yaml:"api_key"`
 }
 
-//MediaBurstRequestTimeout  is the timeout for http request to mediaburst
+// MediaBurstRequestTimeout  is the timeout for http request to mediaburst.
 const MediaBurstRequestTimeout = time.Second * 20
 
-//MediaBurst is the exte MediaBurst
+var _ (sachet.Provider) = (*MediaBurst)(nil)
+
+// MediaBurst is the exte MediaBurst.
 type MediaBurst struct {
 	Config
 }
 
-//NewMediaBurst creates a new
+// NewMediaBurst creates a new.
 func NewMediaBurst(config Config) *MediaBurst {
 	MediaBurst := &MediaBurst{config}
 	return MediaBurst
 }
 
-//Send send sms to n number of people using bulk sms api
+// Send send sms to n number of people using bulk sms api.
 func (c *MediaBurst) Send(message sachet.Message) (err error) {
 	smsURL := "https://api.clockworksms.com/http/send.aspx"
 	var request *http.Request
@@ -37,7 +39,7 @@ func (c *MediaBurst) Send(message sachet.Message) (err error) {
 
 	form := url.Values{"Key": {c.APIKey}, "From": {message.From}, "Content": {message.Text}, "To": message.To}
 
-	//preparing the request
+	// preparing the request.
 	request, err = http.NewRequest("GET", smsURL, strings.NewReader(form.Encode()))
 	if err != nil {
 		return
@@ -45,7 +47,7 @@ func (c *MediaBurst) Send(message sachet.Message) (err error) {
 
 	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 	request.Header.Set("User-Agent", "SachetV1.0")
-	//calling the endpoint
+	// calling the endpoint.
 	httpClient := &http.Client{}
 	httpClient.Timeout = MediaBurstRequestTimeout
 
@@ -55,7 +57,10 @@ func (c *MediaBurst) Send(message sachet.Message) (err error) {
 	}
 	defer resp.Body.Close()
 	var body []byte
-	resp.Body.Read(body)
+	_, err = resp.Body.Read(body)
+	if err != nil {
+		return
+	}
 	if resp.StatusCode == http.StatusOK && err == nil {
 		return
 	}
diff --git a/provider/messagebird/messagebird.go b/provider/messagebird/messagebird.go
index b5dc528..7d45320 100644
--- a/provider/messagebird/messagebird.go
+++ b/provider/messagebird/messagebird.go
@@ -8,6 +8,7 @@ import (
 	messagebird "github.com/messagebird/go-rest-api"
 	sms "github.com/messagebird/go-rest-api/sms"
 	voicemessage "github.com/messagebird/go-rest-api/voicemessage"
+
 	"github.com/messagebird/sachet"
 )
 
@@ -20,6 +21,8 @@ type Config struct {
 	Repeat    int    `yaml:"repeat"`
 }
 
+var _ (sachet.Provider) = (*MessageBird)(nil)
+
 type MessageBird struct {
 	client             *messagebird.Client
 	messageParams      sms.Params
@@ -44,8 +47,7 @@ func NewMessageBird(config Config) *MessageBird {
 	}
 }
 
-func (mb *MessageBird) Send(message sachet.Message) error {
-	var err error = nil
+func (mb *MessageBird) Send(message sachet.Message) (err error) {
 	switch message.Type {
 	case "", "text":
 		_, err = sms.Create(mb.client, message.From, message.To, message.Text, &mb.messageParams)
diff --git a/provider/nexmo/nexmo.go b/provider/nexmo/nexmo.go
index 0b1f54f..f0ba83a 100644
--- a/provider/nexmo/nexmo.go
+++ b/provider/nexmo/nexmo.go
@@ -1,8 +1,9 @@
 package nexmo
 
 import (
+	nexmo "gopkg.in/njern/gonexmo.v1"
+
 	"github.com/messagebird/sachet"
-	"gopkg.in/njern/gonexmo.v1"
 )
 
 type Config struct {
@@ -10,6 +11,8 @@ type Config struct {
 	APISecret string `yaml:"api_secret"`
 }
 
+var _ (sachet.Provider) = (*Nexmo)(nil)
+
 type Nexmo struct {
 	client *nexmo.Client
 }
diff --git a/provider/nowsms/nowsms.go b/provider/nowsms/nowsms.go
index 840edf8..e94df32 100644
--- a/provider/nowsms/nowsms.go
+++ b/provider/nowsms/nowsms.go
@@ -10,20 +10,22 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-// Config is the configuration struct for NowSms provider
+// Config is the configuration struct for NowSms provider.
 type Config struct {
 	User         string   `yaml:"username"`
 	Password     string   `yaml:"password"`
 	PhoneNumbers []string `yaml:"phone_numbers"`
 }
 
-// NowSms contains the necessary values for the NowSms provider
+var _ (sachet.Provider) = (*NowSms)(nil)
+
+// NowSms contains the necessary values for the NowSms provider.
 type NowSms struct {
 	Config
-	HTTPClient *http.Client // The HTTP client to send requests on
+	HTTPClient *http.Client // The HTTP client to send requests on.
 }
 
-// NewNowSms creates and returns a new NowSms struct
+// NewNowSms creates and returns a new NowSms struct.
 func NewNowSms(config Config) *NowSms {
 	return &NowSms{
 		config,
@@ -31,7 +33,7 @@ func NewNowSms(config Config) *NowSms {
 	}
 }
 
-// Send sends SMS to user registered in configuration
+// Send sends SMS to user registered in configuration.
 func (ns *NowSms) Send(message sachet.Message) error {
 	const nowSmsURL = "http://sms-gateway:8800/send"
 
diff --git a/provider/otc/otc.go b/provider/otc/otc.go
index cab3af4..1a90986 100644
--- a/provider/otc/otc.go
+++ b/provider/otc/otc.go
@@ -5,11 +5,12 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
-	"github.com/messagebird/sachet"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"time"
+
+	"github.com/messagebird/sachet"
 )
 
 type Config struct {
@@ -20,8 +21,8 @@ type Config struct {
 	Password         string `yaml:"password"`
 	ProjectID        string `yaml:"project_id"`
 	Insecure         bool   `yaml:"insecure"`
-	token            string
-	otcBaseURL       string
+	Token            string `yaml:"-"`
+	OtcBaseURL       string `yaml:"-"`
 }
 
 type smsRequest struct {
@@ -107,20 +108,20 @@ func (c *OTC) loginRequest() error {
 	tr := http.DefaultTransport.(*http.Transport)
 	tr.TLSClientConfig = &tls.Config{InsecureSkipVerify: c.Insecure}
 
-	client := &http.Client{Timeout: time.Duration(10 * time.Second), Transport: tr}
+	client := &http.Client{Timeout: 10 * time.Second, Transport: tr}
 	resp, err := client.Do(req)
 	if err != nil {
 		return err
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode >= 400 {
+	if resp.StatusCode >= http.StatusBadRequest {
 		return fmt.Errorf("OTC API request failed with HTTP status code %d", resp.StatusCode)
 	}
 
-	c.token = resp.Header.Get("X-Subject-Token")
+	c.Token = resp.Header.Get("X-Subject-Token")
 
-	if c.token == "" {
+	if c.Token == "" {
 		return fmt.Errorf("unable to get auth token")
 	}
 
@@ -146,17 +147,17 @@ func (c *OTC) loginRequest() error {
 	for _, v := range endpointResp.Token.Catalog {
 		if v.Type == "smn" {
 			for _, endpoint := range v.Endpoints {
-				c.otcBaseURL = fmt.Sprintf("%s%s", endpoint.URL, c.ProjectID)
+				c.OtcBaseURL = fmt.Sprintf("%s%s", endpoint.URL, c.ProjectID)
 				continue
 			}
 		}
 
-		if c.otcBaseURL != "" {
+		if c.OtcBaseURL != "" {
 			continue
 		}
 	}
 
-	if c.otcBaseURL == "" {
+	if c.OtcBaseURL == "" {
 		return fmt.Errorf("unable to find snm endpoint")
 	}
 
@@ -164,15 +165,14 @@ func (c *OTC) loginRequest() error {
 }
 
 func (c *OTC) SendRequest(method, resource string, payload *smsRequest, attempts int) (io.Reader, error) {
-	if len(c.token) == 0 {
+	if len(c.Token) == 0 {
 		err := c.loginRequest()
-
 		if err != nil {
 			return nil, err
 		}
 	}
 
-	url := fmt.Sprintf("%s/%s", c.otcBaseURL, resource)
+	url := fmt.Sprintf("%s/%s", c.OtcBaseURL, resource)
 	body, err := json.Marshal(payload)
 	if err != nil {
 		return nil, err
@@ -183,13 +183,13 @@ func (c *OTC) SendRequest(method, resource string, payload *smsRequest, attempts
 		return nil, err
 	}
 	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("X-Auth-Token", c.token)
+	req.Header.Set("X-Auth-Token", c.Token)
 
 	tr := http.DefaultTransport.(*http.Transport)
 	tr.TLSClientConfig = &tls.Config{InsecureSkipVerify: c.Insecure}
 
 	client := &http.Client{
-		Timeout:   time.Duration(10 * time.Second),
+		Timeout:   10 * time.Second,
 		Transport: tr,
 	}
 	resp, err := client.Do(req)
@@ -198,15 +198,14 @@ func (c *OTC) SendRequest(method, resource string, payload *smsRequest, attempts
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode == 401 {
-		// Set empty token to force login
-		c.token = ""
+	if resp.StatusCode == http.StatusUnauthorized {
+		// Set empty token to force login.
+		c.Token = ""
 		if attempts--; attempts > 0 {
 			return c.SendRequest(method, resource, payload, attempts)
-		} else {
-			return nil, err
 		}
-	} else if resp.StatusCode >= 400 {
+		return nil, err
+	} else if resp.StatusCode >= http.StatusBadRequest {
 		return nil, fmt.Errorf("OTC API request %s failed with HTTP status code %d", url, resp.StatusCode)
 	}
 
@@ -218,10 +217,9 @@ func (c *OTC) SendRequest(method, resource string, payload *smsRequest, attempts
 	return bytes.NewReader(body1), nil
 }
 
-//Send send sms to n number of people using bulk sms api
+// Send send sms to n number of people using bulk sms api.
 func (c *OTC) Send(message sachet.Message) (err error) {
 	for _, recipent := range message.To {
-
 		r1 := &smsRequest{
 			Endpoint: recipent,
 			Message:  message.Text,
diff --git a/provider/ovh/ovh.go b/provider/ovh/ovh.go
index 85fc0ed..2ca4416 100644
--- a/provider/ovh/ovh.go
+++ b/provider/ovh/ovh.go
@@ -3,8 +3,9 @@ package ovh
 import (
 	"fmt"
 
-	"github.com/messagebird/sachet"
 	"github.com/ovh/go-ovh/ovh"
+
+	"github.com/messagebird/sachet"
 )
 
 type Config struct {
@@ -19,6 +20,8 @@ type Config struct {
 	Priority          string `yaml:"priority"`
 }
 
+var _ (sachet.Provider) = (*Ovh)(nil)
+
 type Ovh struct {
 	client *ovh.Client
 	config *Config
diff --git a/provider/pushbullet/pushbullet.go b/provider/pushbullet/pushbullet.go
index 0851eaf..57fecfb 100644
--- a/provider/pushbullet/pushbullet.go
+++ b/provider/pushbullet/pushbullet.go
@@ -4,8 +4,9 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/messagebird/sachet"
 	"github.com/xconstruct/go-pushbullet"
+
+	"github.com/messagebird/sachet"
 )
 
 const (
@@ -13,30 +14,30 @@ const (
 	channelTargetType = "channel"
 )
 
-// Config is the configuration struct for the Pushbullet provider
+// Config is the configuration struct for the Pushbullet provider.
 type Config struct {
 	AccessToken string `yaml:"access_token"`
 }
 
-// Pushbullet contains the necessary values for the Pushbullet provider
+var _ (sachet.Provider) = (*Pushbullet)(nil)
+
+// Pushbullet contains the necessary values for the Pushbullet provider.
 type Pushbullet struct {
 	Config
 }
 
-// NewPushbullet creates and returns a new Pushbullet struct
+// NewPushbullet creates and returns a new Pushbullet struct.
 func NewPushbullet(config Config) *Pushbullet {
 	return &Pushbullet{config}
 }
 
-// Send pushes a note to devices registered in configuration
+// Send pushes a note to devices registered in configuration.
 func (c *Pushbullet) Send(message sachet.Message) error {
-
 	for _, recipient := range message.To {
-
-		// create pushbullet client
+		// create pushbullet client.
 		pb := pushbullet.New(c.AccessToken)
 
-		// parse recipient
+		// parse recipient.
 		targetTypeName := strings.SplitN(recipient, ":", 2)
 		if len(targetTypeName) != 2 {
 			return fmt.Errorf("cannot parse recipient %s: expecting targetType:targetName", recipient)
@@ -72,7 +73,6 @@ func (c *Pushbullet) Send(message sachet.Message) error {
 		default:
 			return fmt.Errorf("unrecognised target type: %s", targetType)
 		}
-
 	}
 
 	return nil
diff --git a/provider/sap/sap.go b/provider/sap/sap.go
index 11c9b9f..b86a9f2 100644
--- a/provider/sap/sap.go
+++ b/provider/sap/sap.go
@@ -2,25 +2,28 @@ package sap
 
 import (
 	"fmt"
-	"github.com/messagebird/sachet"
 	"net/http"
 	"strings"
 	"time"
+
+	"github.com/messagebird/sachet"
 )
 
-// Config is the configuration struct for Sap provider
+// Config is the configuration struct for Sap provider.
 type Config struct {
 	URL      string `yaml:"url"`
 	AuthHash string `yaml:"auth_hash"`
 }
 
-// Sap contains the necessary values for the Sap provider
+var _ (sachet.Provider) = (*Sap)(nil)
+
+// Sap contains the necessary values for the Sap provider.
 type Sap struct {
 	Config
-	HTTPClient *http.Client // The HTTP client to send requests on
+	HTTPClient *http.Client // The HTTP client to send requests on.
 }
 
-// NewSap creates and returns a new Sap struct
+// NewSap creates and returns a new Sap struct.
 func NewSap(config Config) *Sap {
 	if config.URL == "" {
 		config.URL = "https://sms-pp.sapmobileservices.com/cmn/xxxxxxxxxx/xxxxxxxxxxx.sms"
@@ -31,12 +34,12 @@ func NewSap(config Config) *Sap {
 	}
 }
 
-// Send sends SMS to user registered in configuration
+// Send sends SMS to user registered in configuration.
 func (c *Sap) Send(message sachet.Message) error {
-
-	// No \n in Text tolerated
+	// No \n in Text tolerated.
 	msg := strings.ReplaceAll(message.Text, "\n", " - ")
-	content := fmt.Sprintf("Version=2.0\nSubject=Alert\n[MSISDN]\nList=%s\n[MESSAGE]\nText=%s\n[SETUP]\nSplitText=yes\n[END]", strings.Join(message.To, ","), msg)
+	content := fmt.Sprintf("Version=2.0\nSubject=Alert\n[MSISDN]\nList=%s\n[MESSAGE]\nText=%s\n[SETUP]\nSplitText=yes\n[END]",
+		strings.Join(message.To, ","), msg)
 
 	request, err := http.NewRequest("POST", c.URL, strings.NewReader(content))
 	if err != nil {
@@ -48,6 +51,7 @@ func (c *Sap) Send(message sachet.Message) error {
 	if err != nil {
 		return err
 	}
+	defer response.Body.Close()
 
 	if response.StatusCode == http.StatusOK && err == nil {
 		return nil
diff --git a/provider/sipgate/sipgate.go b/provider/sipgate/sipgate.go
index c58304a..6ea27b8 100644
--- a/provider/sipgate/sipgate.go
+++ b/provider/sipgate/sipgate.go
@@ -14,18 +14,20 @@ const sipgateURL = "https://api.sipgate.com/v2/sessions/sms"
 
 var sipgateHTTPClient = &http.Client{Timeout: time.Second * 20}
 
-// Config is the configuration struct for Sipgate provider
+// Config is the configuration struct for Sipgate provider.
 type Config struct {
 	Username string `yaml:"username"`
 	Password string `yaml:"password"`
 }
 
-// Sipgate contains the necessary values for the Sipgate provider
+var _ (sachet.Provider) = (*Sipgate)(nil)
+
+// Sipgate contains the necessary values for the Sipgate provider.
 type Sipgate struct {
 	Config
 }
 
-// NewSipgate creates and returns a new Sipgate struct
+// NewSipgate creates and returns a new Sipgate struct.
 func NewSipgate(config Config) *Sipgate {
 	return &Sipgate{config}
 }
@@ -36,7 +38,7 @@ type payload struct {
 	Message   string `json:"message"`
 }
 
-// Send sends SMS to user registered in configuration
+// Send sends SMS to user registered in configuration.
 func (c *Sipgate) Send(message sachet.Message) error {
 	for _, recipient := range message.To {
 		params := payload{
@@ -63,6 +65,7 @@ func (c *Sipgate) Send(message sachet.Message) error {
 		if err != nil {
 			return err
 		}
+		defer response.Body.Close()
 
 		if response.StatusCode != http.StatusNoContent {
 			return fmt.Errorf("Failed sending sms. statusCode: %d", response.StatusCode)
diff --git a/provider/sms77/sms77.go b/provider/sms77/sms77.go
index 8e7315b..2c5ee76 100644
--- a/provider/sms77/sms77.go
+++ b/provider/sms77/sms77.go
@@ -4,23 +4,26 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/messagebird/sachet"
 	"github.com/sms77io/go-client/sms77api"
+
+	"github.com/messagebird/sachet"
 )
 
-// Config is the configuration struct for Sms77 provider
+// Config is the configuration struct for Sms77 provider.
 type Config struct {
 	ApiKey string `yaml:"api_key"`
 	Debug  bool   `yaml:"debug"`
 }
 
-// Sms77 contains the necessary values for the Sms77 provider
+var _ (sachet.Provider) = (*Sms77)(nil)
+
+// Sms77 contains the necessary values for the Sms77 provider.
 type Sms77 struct {
 	client *sms77api.Sms77API
 	config Config
 }
 
-// NewSms77 creates and returns a new Sms77 struct
+// NewSms77 creates and returns a new Sms77 struct.
 func NewSms77(config Config) *Sms77 {
 	client := sms77api.New(sms77api.Options{
 		ApiKey:   config.ApiKey,
@@ -34,7 +37,7 @@ func NewSms77(config Config) *Sms77 {
 	}
 }
 
-// Send sends SMS to user registered in configuration
+// Send sends SMS to user registered in configuration.
 func (s77 *Sms77) Send(message sachet.Message) error {
 	var err error = nil
 	switch message.Type {
diff --git a/provider/smsc/smsc.go b/provider/smsc/smsc.go
index f8c9382..bfe73c3 100644
--- a/provider/smsc/smsc.go
+++ b/provider/smsc/smsc.go
@@ -2,10 +2,11 @@ package smsc
 
 import (
 	"fmt"
-	"github.com/messagebird/sachet"
 	"net/http"
 	"net/url"
 	"time"
+
+	"github.com/messagebird/sachet"
 )
 
 type Config struct {
@@ -15,6 +16,8 @@ type Config struct {
 
 const SmscRequestTimeout = time.Second * 60
 
+var _ (sachet.Provider) = (*Smsc)(nil)
+
 type Smsc struct {
 	Login    string
 	Password string
@@ -29,15 +32,16 @@ func (c *Smsc) Send(message sachet.Message) (err error) {
 	for _, number := range message.To {
 		err = c.SendOne(message, number)
 		if err != nil {
-			return fmt.Errorf("Failed to make API call to smsc:%s", err)
+			return fmt.Errorf("Failed to make API call to smsc: %w", err)
 		}
 	}
 	return
 }
 
-func (c *Smsc) SendOne(message sachet.Message, PhoneNumber string) (err error) {
-	encoded_message := url.QueryEscape(message.Text)
-	smsURL := fmt.Sprintf("https://smsc.ru/sys/send.php?login=%s&psw=%s&phones=%s&sender=%s&fmt=0&mes=%s", c.Login, c.Password, PhoneNumber, message.From, encoded_message)
+func (c *Smsc) SendOne(message sachet.Message, phoneNumber string) (err error) {
+	encodedMessage := url.QueryEscape(message.Text)
+	smsURL := fmt.Sprintf("https://smsc.ru/sys/send.php?login=%s&psw=%s&phones=%s&sender=%s&fmt=0&mes=%s",
+		c.Login, c.Password, phoneNumber, message.From, encodedMessage)
 	var request *http.Request
 	var resp *http.Response
 	request, err = http.NewRequest("GET", smsURL, nil)
@@ -52,7 +56,10 @@ func (c *Smsc) SendOne(message sachet.Message, PhoneNumber string) (err error) {
 	}
 	defer resp.Body.Close()
 	var body []byte
-	resp.Body.Read(body)
+	_, err = resp.Body.Read(body)
+	if err != nil {
+		return
+	}
 	if resp.StatusCode == http.StatusOK && err == nil {
 		return
 	}
diff --git a/provider/telegram/telegram.go b/provider/telegram/telegram.go
index 2d5ec59..7f260bb 100644
--- a/provider/telegram/telegram.go
+++ b/provider/telegram/telegram.go
@@ -1,9 +1,11 @@
 package telegram
 
 import (
-	"github.com/messagebird/sachet"
-	"gopkg.in/telegram-bot-api.v4"
 	"strconv"
+
+	tgbotapi "gopkg.in/telegram-bot-api.v4"
+
+	"github.com/messagebird/sachet"
 )
 
 type Config struct {
@@ -12,6 +14,8 @@ type Config struct {
 	DisableWebPagePreview bool   `yaml:"disable_web_page_preview"`
 }
 
+var _ (sachet.Provider) = (*Telegram)(nil)
+
 type Telegram struct {
 	bot    *tgbotapi.BotAPI
 	config *Config
diff --git a/provider/tencentcloud/tencentcloud.go b/provider/tencentcloud/tencentcloud.go
index 59c4a6a..956e4df 100644
--- a/provider/tencentcloud/tencentcloud.go
+++ b/provider/tencentcloud/tencentcloud.go
@@ -2,12 +2,15 @@ package tencentcloud
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
-	"github.com/messagebird/sachet"
+
 	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common"
-	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common/errors"
+	tcError "github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common/errors"
 	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common/profile"
 	sms "github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/sms/v20190711"
+
+	"github.com/messagebird/sachet"
 )
 
 type Config struct {
@@ -21,12 +24,14 @@ type Config struct {
 	Truncate     bool   `yaml:"truncate"`
 }
 
+var _ (sachet.Provider) = (*TencentCloud)(nil)
+
 type TencentCloud struct {
 	client *sms.Client
 	config *Config
 }
 
-func NewTencentCloud(config Config) (*TencentCloud, error) {
+func NewTencentCloud(config Config) *TencentCloud {
 	credential := common.NewCredential(
 		config.SecretId,
 		config.SecretKey,
@@ -39,8 +44,7 @@ func NewTencentCloud(config Config) (*TencentCloud, error) {
 	return &TencentCloud{
 		client: client,
 		config: &config,
-	}, nil
-
+	}
 }
 
 func truncateString(str string, num int) string {
@@ -55,7 +59,6 @@ func truncateString(str string, num int) string {
 }
 
 func (tencentcloud *TencentCloud) Send(message sachet.Message) error {
-	var err error = nil
 	switch message.Type {
 	case "", "text":
 		request := sms.NewSendSmsRequest()
@@ -70,13 +73,19 @@ func (tencentcloud *TencentCloud) Send(message sachet.Message) error {
 		request.TemplateID = common.StringPtr(tencentcloud.config.TemplateCode)
 		request.PhoneNumberSet = common.StringPtrs(message.To)
 		response, err := tencentcloud.client.SendSms(request)
-		if _, ok := err.(*errors.TencentCloudSDKError); ok {
+
+		var errTencentCloudSDKError *tcError.TencentCloudSDKError
+		if errors.As(err, &errTencentCloudSDKError) {
 			fmt.Printf("An API error has returned: %s", err)
 			return err
 		}
-		b, _ := json.Marshal(response.Response)
+
+		b, err := json.Marshal(response.Response)
+		if err != nil {
+			return err
+		}
 		fmt.Printf("%s", b)
 	}
-	return err
 
+	return nil
 }
diff --git a/provider/textmagic/textmagic.go b/provider/textmagic/textmagic.go
index 63a8bd4..1b397bc 100644
--- a/provider/textmagic/textmagic.go
+++ b/provider/textmagic/textmagic.go
@@ -5,8 +5,9 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/messagebird/sachet"
 	textmagic "github.com/textmagic/textmagic-rest-go-v2/v2"
+
+	"github.com/messagebird/sachet"
 )
 
 type Config struct {
@@ -14,6 +15,8 @@ type Config struct {
 	APIKey   string `yaml:"api_key"`
 }
 
+var _ (sachet.Provider) = (*TextMagic)(nil)
+
 type TextMagic struct {
 	client *textmagic.APIClient
 	auth   context.Context
@@ -33,11 +36,10 @@ func NewTextMagic(config Config) *TextMagic {
 	}
 }
 
-func (tm *TextMagic) Send(message sachet.Message) error {
-	var err error = nil
+func (tm *TextMagic) Send(message sachet.Message) (err error) {
 	switch message.Type {
 	case "", "text":
-		joinedTo := strings.Join(message.To[:], ",")
+		joinedTo := strings.Join(message.To, ",")
 		_, _, err = tm.client.TextMagicApi.SendMessage(tm.auth, textmagic.SendMessageInputObject{
 			Text:   message.Text,
 			Phones: joinedTo,
diff --git a/provider/turbosms/turbosms.go b/provider/turbosms/turbosms.go
index 4c2060a..cfdb07e 100644
--- a/provider/turbosms/turbosms.go
+++ b/provider/turbosms/turbosms.go
@@ -13,11 +13,14 @@ import (
 	"github.com/messagebird/sachet"
 )
 
-// sachet section
+// sachet section.
 type Config struct {
 	Alogin    string `yaml:"login"`
 	Apassword string `yaml:"password"`
 }
+
+var _ (sachet.Provider) = (*Turbosms)(nil)
+
 type Turbosms struct {
 	Login    string
 	Password string
@@ -28,7 +31,7 @@ func NewTurbosms(config Config) *Turbosms {
 	return Turbosms
 }
 
-// http  url for  turbosms
+// http  url for  turbosms.
 var urlSoap string = "http://turbosms.in.ua/api/soap.html"
 
 type SoapBody struct {
@@ -75,7 +78,11 @@ func SoapEncode(contents interface{}) ([]byte, error) {
 		return nil, err
 	}
 	data = append([]byte("\n"), data...)
-	env := SoapEnvelopeReqest{Id1: "http://schemas.xmlsoap.org/soap/envelope/", Id2: "http://turbosms.in.ua/api/Turbo", Body: SoapBody{Contents: data}}
+	env := SoapEnvelopeReqest{
+		Id1:  "http://schemas.xmlsoap.org/soap/envelope/",
+		Id2:  "http://turbosms.in.ua/api/Turbo",
+		Body: SoapBody{Contents: data},
+	}
 	return xml.MarshalIndent(&env, "", "  ")
 }
 
@@ -89,12 +96,12 @@ func SoapDecode(data []byte, contents interface{}) error {
 }
 
 func Request(c *http.Client, url string, payload []byte) ([]byte, error, int) {
-
 	resp, err := c.Post(url, "text/xml", bytes.NewBuffer(payload))
 	statuscode := resp.StatusCode
 	if err != nil {
 		return nil, err, statuscode
 	}
+	defer resp.Body.Close()
 
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
@@ -115,7 +122,7 @@ func (c *Turbosms) Send(message sachet.Message) (err error) {
 		Timeout: 15 * time.Second,
 		Jar:     cookieJar,
 	}
-	reply, err, statusreply := Request(clientConfig, urlSoap, []byte(data))
+	reply, err, statusreply := Request(clientConfig, urlSoap, data)
 	if err != nil {
 		return err
 	}
@@ -126,17 +133,16 @@ func (c *Turbosms) Send(message sachet.Message) (err error) {
 		return err
 	}
 	// Request
-	replysms, err, statusreplysms := Request(clientConfig, urlSoap, []byte(datasms))
+	replysms, err, statusreplysms := Request(clientConfig, urlSoap, datasms)
 	if err != nil {
 		return err
-
 	}
 	if statusreply == 200 && statusreplysms == 200 && err == nil {
 		return nil
 	}
 
 	var resp getAuthResponse
-	err = SoapDecode([]byte(reply), &resp)
+	err = SoapDecode(reply, &resp)
 	if err != nil {
 		return err
 	}
diff --git a/provider/twilio/twilio.go b/provider/twilio/twilio.go
index d3d30a0..e595e6a 100644
--- a/provider/twilio/twilio.go
+++ b/provider/twilio/twilio.go
@@ -2,6 +2,7 @@ package twilio
 
 import (
 	"github.com/carlosdp/twiliogo"
+
 	"github.com/messagebird/sachet"
 )
 
@@ -10,6 +11,8 @@ type Config struct {
 	AuthToken  string `yaml:"auth_token"`
 }
 
+var _ (sachet.Provider) = (*Twilio)(nil)
+
 type Twilio struct {
 	client twiliogo.Client
 }