Response Rate Limiting

This plugin allows you to limit the number of requests a developer can make based on a custom response header returned by the upstream service. You can arbitrary set as many rate-limiting objects (or quotas) as you want and instruct Kong to increase or decrease them by any number of units. Each custom rate-limiting object can limit the inbound requests per seconds, minutes, hours, days, months or years.

If the underlying Service/Route (or deprecated API entity) has no authentication layer, the Client IP address will be used, otherwise the Consumer will be used if an authentication plugin has been configured.

Terminology

• plugin: a plugin executing actions inside Kong before or after a request has been proxied to the upstream API.
• Service: the Kong entity representing an external upstream API or microservice.
• Route: the Kong entity representing a way to map downstream requests to upstream services.
• Consumer: an entity that makes requests for Kong to proxy; it represents either a user or an external service.
• Credential: a unique string associated with a Consumer, also referred to as an API key.
• Upstream service: this refers to your own API/service sitting behind Kong, to which client requests are forwarded.
• API: a legacy entity used to represent your upstream services. Deprecated in favor of Services since CE 0.13.0 and EE 0.32.

Configuration

This plugin is compatible with requests with the following protocols:

• http
• https

This plugin is partially compatible with DB-less mode.

The plugin will run fine with the local policy (which doesn’t use the database) or the redis policy (which uses an independent Redis, so it is compatible with DB-less).

The plugin will not work with the cluster policy, which requires writes to the database.

Enabling the plugin on a Service

$ curl -X POST http://kong:8001/services/{service}/plugins \
    --data "name=response-ratelimiting"  \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

plugins:
- name: response-ratelimiting
  service: {service}
  config: 
    limits.{limit_name}: 
    limits.{limit_name}.minute: 10

{service} is the id or name of the Service that this plugin configuration will target.

Enabling the plugin on a Route

$ curl -X POST http://kong:8001/routes/{route}/plugins \
    --data "name=response-ratelimiting"  \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

plugins:
- name: response-ratelimiting
  route: {route}
  config: 
    limits.{limit_name}: 
    limits.{limit_name}.minute: 10

{route} is the id or name of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

$ curl -X POST http://kong:8001/consumers/{consumer}/plugins \
    --data "name=response-ratelimiting"  \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

plugins:
- name: response-ratelimiting
  consumer: {consumer}
  config: 
    limits.{limit_name}: 
    limits.{limit_name}.minute: 10

{consumer} is the id or username of the Consumer that this plugin configuration will target.

You can combine consumer.id and service.id in the same request, to further narrow the scope of the plugin.

Enabling the plugin on an API

If you are using an older version of Kong with the legacy API entity (deprecated in favor of Services since CE 0.13.0 and EE 0.32.), you can configure this plugin on top of such an API by making the following request:

$ curl -X POST http://kong:8001/apis/{api}/plugins \
    --data "name=response-ratelimiting"  \
    --data "config.limits.{limit_name}=" \
    --data "config.limits.{limit_name}.minute=10"

• api: either id or name of the API that this plugin configuration will target.

Global plugins

A plugin which is not associated to any Service, Route, or Consumer (or API, if you are using an older version of Kong) is considered "global", and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

• Using a database, all plugins can be configured using the http://kong:8001/plugins/ endpoint.
• Without a database, all plugins can be configured via the plugins: entry on the declarative configuration file.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

Configuring Quotas

After adding the plugin, you can increment the configured limits by adding the following response header:

Header-Name: Limit=Value [,Limit=Value]

Since X-Kong-Limit is the default header name (you can optionally change it), it will look like:

X-Kong-Limit: limitname1=2, limitname2=4

That will increment the limit limitname1 by 2 units, and limitname2 by 4 units.

You can optionally increment more than one limit by comma separating the entries. The header will be removed before returning the response to the original client.

Headers sent to the client

When this plugin is enabled, Kong will send some additional headers back to the client telling how many units are available and how many are allowed. For example if you created a limit/quota called “Videos” with a per-minute limit:

X-RateLimit-Limit-Videos-Minute: 10
X-RateLimit-Remaining-Videos-Minute: 9

or it will return a combination of more time limits, if more than one is being set:

X-RateLimit-Limit-Videos-Second: 5
X-RateLimit-Remaining-Videos-Second: 5
X-RateLimit-Limit-Videos-Minute: 10
X-RateLimit-Remaining-Videos-Minute: 10

If any of the limits configured is being reached, the plugin will return a HTTP/1.1 429 status code and an empty body.

Upstream Headers

The plugin will append the usage headers for each limit before proxying it to the upstream service, so that you can properly refuse to process the request if there are no more limits remaining. The headers are in the form of X-RateLimit-Remaining-{limit_name}, like:

X-RateLimit-Remaining-Videos: 3
X-RateLimit-Remaining-Images: 0