diff --git a/src/app/alert.model.ts b/src/app/alert.model.ts
new file mode 100644
index 0000000..7155150
--- /dev/null
+++ b/src/app/alert.model.ts
@@ -0,0 +1,11 @@
+export enum AlertType {
+  success = 'success',
+  info = 'info',
+  warning = 'warning',
+  danger = 'danger',
+}
+
+export interface Alert {
+  type: AlertType;
+  message: string;
+}
diff --git a/src/app/app.module.ts b/src/app/app.module.ts
index 11c5132..eaf21ea 100644
--- a/src/app/app.module.ts
+++ b/src/app/app.module.ts
@@ -2,9 +2,9 @@ import { HttpClientModule } from '@angular/common/http';
 import { NgModule } from '@angular/core';
 import { FormsModule } from '@angular/forms';
 import { BrowserModule } from '@angular/platform-browser';
-import { NgbCollapseModule } from '@ng-bootstrap/ng-bootstrap';
+import { NgbAlertModule, NgbCollapseModule } from '@ng-bootstrap/ng-bootstrap';
 import { HttpClientInMemoryWebApiModule } from 'angular-in-memory-web-api';
-import { environment } from 'src/environments/environment';
+import { environment } from '../environments/environment';
 import { AppRoutingModule } from './app-routing.module';
 import { AppComponent } from './app.component';
 import { DashboardComponent } from './dashboard/dashboard.component';
@@ -36,6 +36,7 @@ import { SearchInputComponent } from './search-input/search-input.component';
     FormsModule,
     AppRoutingModule,
     NgbCollapseModule,
+    NgbAlertModule,
     HttpClientModule,
     environment.production
       ? []
diff --git a/src/app/hero.service.ts b/src/app/hero.service.ts
index 3384009..c92bbd4 100644
--- a/src/app/hero.service.ts
+++ b/src/app/hero.service.ts
@@ -2,7 +2,8 @@ import { HttpClient, HttpHeaders } from '@angular/common/http';
 import { Injectable } from '@angular/core';
 import { Observable, of } from 'rxjs';
 import { catchError, tap } from 'rxjs/operators';
-import { environment } from '../environments/environment';
+import { environment } from 'src/environments/environment';
+import { AlertType } from './alert.model';
 import { Hero } from './hero.model';
 import { MessageService } from './message.service';
 
@@ -20,79 +21,92 @@ export class HeroService {
   };
 
   constructor(
-    private http: HttpClient,
-    private messageService: MessageService
+    private messageService: MessageService,
+    private http: HttpClient
   ) {}
 
+  // GET /heroes
   getHeroes(): Observable<Hero[]> {
     return this.http.get<Hero[]>(this.heroesUrl, this.httpOptions).pipe(
-      tap(() => this.log('fetched heroes')),
+      tap((heroes) => {
+        this.log(`fetched ${heroes.length} heroes`);
+      }),
       catchError(this.handleError<Hero[]>('getHeroes', []))
     );
   }
 
+  // GET /heroes/id
   getHero(id: number): Observable<Hero> {
-    const url = `${this.heroesUrl}/${id}`;
-
-    return this.http.get<Hero>(url, this.httpOptions).pipe(
-      tap(() => this.log(`fetched hero id=${id}`)),
-      catchError(this.handleError<Hero>('getHeroes'))
-    );
+    return this.http
+      .get<Hero>(`${this.heroesUrl}/${id}`, this.httpOptions)
+      .pipe(
+        tap(() => this.log(`fetched hero id=${id}.`)),
+        catchError(this.handleError<Hero>('getHero'))
+      );
   }
 
+  // PUT /heroes/id
   updateHero(hero: Hero): Observable<Hero> {
     const url = `${this.heroesUrl}/${hero.id}`;
 
     return this.http.put<Hero>(url, hero, this.httpOptions).pipe(
-      tap(() => this.log(`updated hero id=${hero.id}`)),
-      catchError(this.handleError<Hero>('updateHeroes'))
+      tap(() => this.log(`updated hero id=${hero.id}.`, AlertType.success)),
+      catchError(this.handleError<Hero>('updateHero'))
     );
   }
 
+  // POST /heroes
   addHero(hero: Hero): Observable<Hero> {
-    return this.http.post(this.heroesUrl, hero, this.httpOptions).pipe(
-      tap((newHero: Hero) => this.log(`added hero w/ id=${newHero.id}`)),
+    return this.http.post<Hero>(this.heroesUrl, hero, this.httpOptions).pipe(
+      tap((newHero) =>
+        this.log(`added hero w/ id=${newHero.id}.`, AlertType.success)
+      ),
       catchError(this.handleError<Hero>('addHero'))
     );
   }
 
+  // DELETE /heroes/id
   deleteHero(hero: Hero): Observable<any> {
     const url = `${this.heroesUrl}/${hero.id}`;
 
-    return this.http.delete<any>(url, this.httpOptions).pipe(
-      tap(() => this.log(`deleted hero id=${hero.id}`)),
+    return this.http.delete<Hero>(url, this.httpOptions).pipe(
+      tap(() => this.log(`deleted hero id=${hero.id}.`, AlertType.success)),
       catchError(this.handleError<Hero>('deleteHero'))
     );
   }
 
+  // GET /heroes/?name=term
   searchHeroes(term: string): Observable<Hero[]> {
-    if (!term.trim()) {
+    if (!(term && term.trim())) {
       return of([]);
     }
 
     return this.http
       .get<Hero[]>(`${this.heroesUrl}/?name=${term}`, this.httpOptions)
       .pipe(
-        tap((heroes) =>
+        tap((heroes) => {
           heroes && heroes.length
-            ? this.log(`found heroes matching "${term}"`)
-            : this.log(`no heroes matching "${term}"`)
-        ),
+            ? this.log(`found ${heroes.length} heroes matching term=${term}`)
+            : this.log(`no heroes matching term=${term}`, AlertType.warning);
+        }),
         catchError(this.handleError<Hero[]>('searchHeroes', []))
       );
   }
 
+  private log(message: string, type = AlertType.info) {
+    this.messageService.add({
+      message: `HeroService: ${message}`,
+      type,
+    });
+  }
+
   private handleError<T>(operation = 'operation', result?: T) {
     return (error: any): Observable<T> => {
       console.log(error);
 
-      this.log(`${operation} failed: ${error.message}`);
+      this.log(`${operation} failed: ${error.message}`, AlertType.danger);
 
-      return of(result as T);
+      return of(result);
     };
   }
-
-  private log(message: string) {
-    this.messageService.add(`HeroService: ${message}`);
-  }
 }
diff --git a/src/app/heroes/heroes.component.html b/src/app/heroes/heroes.component.html
index 67bf863..a9a7997 100644
--- a/src/app/heroes/heroes.component.html
+++ b/src/app/heroes/heroes.component.html
@@ -6,7 +6,10 @@ <h2>My Heroes</h2>
   </div>
 
   <div class="col-12 col-sm-6">
-    <app-search-input (search)="onFilter($event)"></app-search-input>
+    <app-search-input
+      [label]="'Filter'"
+      (search)="onFilter($event)"
+    ></app-search-input>
   </div>
 </div>
 
diff --git a/src/app/message.service.ts b/src/app/message.service.ts
index d72412e..8188ac3 100644
--- a/src/app/message.service.ts
+++ b/src/app/message.service.ts
@@ -1,16 +1,25 @@
 import { Injectable } from '@angular/core';
+import { Alert } from './alert.model';
 
 @Injectable({
   providedIn: 'root',
 })
 export class MessageService {
-  messages: string[] = [];
+  private alerts: Alert[] = [];
 
-  add(message: string) {
-    this.messages.push(message);
+  getMessages(): Alert[] {
+    return this.alerts;
+  }
+
+  add(alert: Alert) {
+    this.alerts.push(alert);
   }
 
   clear() {
-    this.messages = [];
+    this.alerts = [];
+  }
+
+  close(alert: Alert) {
+    this.alerts.splice(this.alerts.indexOf(alert), 1);
   }
 }
diff --git a/src/app/messages/messages.component.html b/src/app/messages/messages.component.html
index 89f32d6..5163cf2 100644
--- a/src/app/messages/messages.component.html
+++ b/src/app/messages/messages.component.html
@@ -1,4 +1,4 @@
-<div *ngIf="messageService.messages.length">
+<div *ngIf="messageService.getMessages().length">
   <h2>Messages</h2>
 
   <button
@@ -9,9 +9,9 @@ <h2>Messages</h2>
     Clear
   </button>
 
-  <div *ngFor="let message of messageService.messages">
-    <div class="alert alert-success" role="alert">
-      {{ message }}
-    </div>
+  <div *ngFor="let alert of messageService.getMessages()">
+    <ngb-alert [type]="alert.type" (close)="close(alert)">
+      {{ alert.message }}
+    </ngb-alert>
   </div>
 </div>
diff --git a/src/app/messages/messages.component.ts b/src/app/messages/messages.component.ts
index 71a8ef8..94606ac 100644
--- a/src/app/messages/messages.component.ts
+++ b/src/app/messages/messages.component.ts
@@ -1,4 +1,5 @@
 import { Component } from '@angular/core';
+import { Alert } from '../alert.model';
 import { MessageService } from '../message.service';
 
 @Component({
@@ -8,4 +9,8 @@ import { MessageService } from '../message.service';
 })
 export class MessagesComponent {
   constructor(public messageService: MessageService) {}
+
+  close(alert: Alert) {
+    this.messageService.close(alert);
+  }
 }