🔑 api_keys – Secure API keys for your Rails app

api_keys makes it simple to add secure, production-ready API key authentication to any Rails app. Generate keys, restrict scopes, auto-expire tokens, revoke tokens, gate endpoints. It also provides a self-serve dashboard for your users to self-issue and manage their API keys themselves. All tokens are hashed securely by default, and never stored in plaintext.

[ 🟢 Live interactive demo website ]

Check out my other 💎 Ruby gems: allgood · usage_credits · profitable · nondisposable

Installation

Add this line to your application's Gemfile:

gem "api_keys"

And then bundle install. After the gem is installed, run the generator and migration:

rails g api_keys:install
rails db:migrate

And you're done!

Quick Start

Just add has_api_keys to your desired model. For example, if you want your User records to have API keys, you'd have:

class User < ApplicationRecord
  has_api_keys
end

You can also customize how many maximum keys your users can have by passing a block to has_api_keys, like this:

class User < ApplicationRecord
  has_api_keys do
    max_keys 10 # only 10 active API keys per user allowed
    require_name true # always require users to set a name for each API key
  end
end

It'd work the same if you want your Organization or your Project records to have API keys.

Mount the dashboard engine

The goal of api_keys is to allow you to turn your Rails app into an API platform with secure key authentication in minutes, as in: drop in this gem and you're pretty much done with API key management.

To achieve that, the gem provides a ready-to-go dashboard you can just mount in your routes.rb like this:

mount ApiKeys::Engine => '/settings/api-keys'

Now your users can:

• self-issue new API keys
• set expiration dates
• attach scopes / permissions to individual keys
• add and edit the key names
• revoke instantly
• see the status of all their keys

It provides an UI with everything you'd expect from an API keys dashboard, working right out of the box:

To make the experience between your app and the api_keys dashboard more seamless, you can configure a return_url and return_text so your users can quickly go back to your app or settings page (in the screenshot above, that's the "Home" links, text customizable)

You can check out the dashboard on the live demo website.

How it works

Issuing new API keys

If you want to write your own front-end instead of using the provided dashboard, or just want to issue API keys at any point, you can do it with create_api_key!:

@api_key = @user.create_api_key!(
  name: "my-key",
  scopes: "['read', 'write']",
  expires_at: 42.days.from_now
)

# Get the plaintext token only available upon creation
plaintext_token = @api_key.token
# => ak_123abc...

For security reasons, the gem does not store the generated key in the database.

We only store a salted hash, so the API key / API token itself is only available in plaintext immediately after creation, as @api_key.token – the .token method won't work any other time.

With this token, your users can make calls to your endpoints by attaching it as an "Authorization: Bearer ak_123abc..." in their HTTP calls headers, like this:

curl -X GET -H "Authorization: Bearer ak_123abc..."   "http://example.com/api/endpoint"

Listing all keys for users

Of course, you can list all API keys for any record like this:

  @user.api_keys

You can filter by active keys, expired keys, revoked keys:

  @user.api_keys.active
  @user.api_keys.expired
  @user.api_keys.revoked
  @user.api_keys.inactive # expired or revoked

Useful API key methods

Check if an API key is still active and therefore allowed to perform actions:

@api_key.active?
# => true

Or expired:

@api_key.expired?
# => false

You can revoke (disable, make inactive) any API key at any point like this:

@api_key.revoke!

And you can check if an API key is revoked like this:

@api_key.revoked?
# => true

And for any API key, you can always display a safe, user-friendly masked token to display on user interfaces so users can easily identify their keys:

@api_key.masked_token
# => "ak_demo_••••yZn9"

Scopes: define and verify API Key permissions

Users can limit what each API key does by selecting scopes, and you can define those scopes.

In the config/initializers/api_keys.rb initializer generated when you installed the gem, you'll find an option to define global scopes:

config.default_scopes = ["read", "write"]

These will be the available permissions you'll see, for example, in the API Keys dashboard:

You can also define per-model scopes by passing the option to the has_api_keys block, which overrides global defaults:

class User < ApplicationRecord
  has_api_keys do
    max_keys 10
    default_scopes %w[read write admin]
  end
end

You can get as granular with your scopes as you'd like, think for example AWS-like strings of the form: "s3:GetObject" – how you set this up is up to you! Scopes take any string: we recommend sticking to simple verbs ("read", "write") or "resource:action" (case-sensitive!)

You can check if an API key is allowed to do actions by checking its scopes:

@api_key.allows_scope?("read")
# => true

Controllers: secure your API endpoints

To add the api_keys functionality to your controllers, just use the ApiKeys::Controller concern and you'll have all controller methods available:

class ApiController < ApplicationController
  include ApiKeys::Controller # provides authenticate_api_key! and current_api_key_owner
end

With this, you get the authenticate_api_key! and current_api_key_owner methods, which come in handy to build your key-gated actions.

Require an API key for an endpoint

If you just want to check the presence of a valid (active, non-expired, non-revoked) API key for an endpoint, you can do:

before_action :authenticate_api_key!

And of course, if you want to have unauthenticated endpoints:

before_action :authenticate_api_key!, except: [:unauthenticated_endpoint]

authenticate_api_key! will return 401 Unauthenticated for anything that's not a valid API key.

It will also load the valid API key, if any, to a current_api_key variable, that returns an API Key object (ApiKeys::ApiKey) on which you can call all the methods we've outlined above, and access any attribute, like:

current_api_key.expires_at
# => 2025-05-25 05:25:05.250525000 UTC +00:00

If the API key has an owner, you can also access it either with current_api_key.owner or with the helper method current_api_key_owner

For example, if the owner of the API key is a User, you might do something like:

current_api_key_owner.email
# => john.doe@example.com

Require a scope for an endpoint

You can require a specific scope for any endpoint like:

authenticate_api_key!(scope: "write")

It may be cleaner if you pass it as a Proc to before_action – and it may result in better-organized code if you do it endpoint-per-endpoint, immediately before each method definition, like this:

before_action -> { authenticate_api_key!(scope: "write") }, only: [:write_action]
def write_action
  # We'll only get here if the API key is active AND it has the right scope, so execute the actual logic of the endpoint and return success:
  render json: {
    # Your success JSON...
  }, status: :ok
end

Rate limit your API endpoints

Rails 8 introduced the native, built-in rate_limit to easily rate limit your endpoints, so Rack::Attack is no longer necessary! While this is not an api_keys feature per se, I thought it'd be nice to include an example here because it pairs so well with api_keys.

For example, if you want to rate limit an endpoint to only accept 2 requests each 10 seconds, per API key, you'd do something like:

before_action -> { authenticate_api_key! }, only: [:rate_limited_action]
rate_limit to: 2, within: 10.seconds,
            by: -> { current_api_key&.id }, # Limit per API key ID
            with: -> { render json: { error: "rate_limited", message: "Too many requests (max 2 per 10 seconds per key). Please wait." }, status: :too_many_requests },
            only: [:rate_limited_action]
def rate_limited_action
  render json: {
    # Success JSON
  }, status: :ok
end

This rate_limit feature depends on Rails 8+ and an active, well-configured cache store, like solid_cache, which comes by default in Rails 8.

If you're still on early versions of Rails, you can still use api_keys! No need to implement rate_limit – just an idea if you're already on Rails 8!

Configuration and settings

The gem installation creates an initializer at config/initializers/api_keys.rb

The default initializer is self-explanatory and self-documented, please consider spending a bit of time reading through it if you want to fine-tune the gem.

Some highlights:

Accept API keys via query params instead of Authentication HTTP headers

By default, the api_key gem expects API keys to come exclusively as HTTP Authentication Bearer tokens, for security purposes. But you can allow users to make requests to your endpoints with the API key token passed as a URL query param too, like this:

https://example.com/api/endpoint?api_key=ak_123abc...

This is not recommended security-wise because you'll be leaking API tokens everywhere in your logs, but if you want to enable this, just set the query param name you're expecting the API key token to be in:

config.query_param = "api_key"

Changing the hashing function to bcrypt for maximum security

By default, the api_keys gem hashes tokens using sha256, for fast token lookup and low-latency API authentication. Tokens are salted via their prefix, and only stored as secure digests.

If you need slower, password-grade hashing (e.g., for extremely sensitive tokens), you can switch to bcrypt:

config.hash_strategy = :bcrypt

Note: bcrypt is ~50–100x slower than SHA256. For most API use cases, sha256 is more than sufficient.

sha256 has O(1) lookup, bcrypt doesn't. This means that if you switch to bcrypt, you may observe ~100ms lags on every API call, for every token auth that's not cached.

For 99% of APIs, sha256 is more than secure enough — and far better for performance.

Increase cache TTL

We cache token lookups to improve performance, especially for repeated requests. This keeps bcrypt and sha256 strategies fast under load.

By default, we use a 5-second TTL, which offers a strong balance: most requests benefit from caching, while revoked keys stop working almost immediately.

If security is your top priority (e.g. rapid revocation after suspected key compromise), you can disable caching entirely:

config.cache_ttl = 0.seconds # disables caching

If performance matters more than real-time revocation, increase the TTL to reduce DB hits:

config.cache_ttl = 2.minutes # boosts performance at cost of slower revocation

⚠️ Security note: Revoked keys may remain valid for up to cache_ttl. For strict real-time revocation, set cache_ttl = 0.

Callbacks: analytics, logging, usage monitoring & auditing

The gem offers two callbacks that get executed every single time an API key is checked and authenticated (through authenticate_api_key! in controllers, for example)

You can define logic for them:

config.before_authentication = ->(request) { Rails.logger.info "Authenticating request: #{request.uuid}" }

config.after_authentication = ->(result) { MyAnalytics.track_auth(result) }

This is especially useful if you want to build custom monitoring, usage tracking or auditing systems on top of the api_keys gem.

Since these callbacks get called every single time an endpoint request is made, we can't just execute the code synchronously, blocking the thread and making the endpoint lag. Instead, we enqueue an async job that process the callback code, however long it is. You can configure which queue these jobs get enqueued to.

The downside of this, of course, is that callbacks will only work if you have a valid, well-configured Active Job backend for your Rails app, like Sidekiq or solid_queue, which comes by default in Rails 8. If Active Job is not well configured, well, your callbacks just won't get executed.

There's also a track_requests_count config option that you can turn on so the gem keeps track of how many requests has each API key made. When this is on, you may access the count like this:

@api_key.requests_count
# => 4567

But again, this is turned off by default for performance purposes, and depends on having a working, well-configured Active Job backend.

Enterprise-ready by design

The api_keys gem ships with:

• Flexible storage
• Async hooks
• ActiveJob support
• Polymorphic ownership (User, Org, etc.)
• Custom scopes
• Production caching
• Tracking of last time each key was used
• Usage tracking
• SHA256 fallback

Making it enterprise-ready, built with extensibility and compliance in mind.

Roadmap

• Automatic rotation policy helpers
• Key-pair / HMAC option

Demo Rails app

There's a demo Rails app showcasing the features in the api_keys gem under test/dummy. It's currently deployed to apikeys.rameerez.com. If you want to run it yourself locally, you can just clone this repo, cd into the test/dummy folder, and then bundle and rails s to launch it. You can examine the code of the demo app to better understand the gem.

Testing

Run the test suite with bundle exec rake test

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rameerez/api_keys. Our code of conduct is: just be nice and make your mom proud of what you do and post online.

License

The gem is available as open source under the terms of the MIT License.