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[](license.md)
Basic rate-limiting middleware for [Express](http://expressjs.com/). Use to
limit repeated requests to public APIs and/or endpoints such as password reset.
Plays nice with
[express-slow-down](https://www.npmjs.com/package/express-slow-down) and
[ratelimit-header-parser](https://www.npmjs.com/package/ratelimit-header-parser).
## Usage
The [full documentation](https://express-rate-limit.mintlify.app/overview) is
available on-line.
```ts
import { rateLimit } from 'express-rate-limit'
const limiter = rateLimit({
windowMs: 15 * 60 * 1000, // 15 minutes
limit: 100, // Limit each IP to 100 requests per `window` (here, per 15 minutes).
standardHeaders: 'draft-7', // draft-6: `RateLimit-*` headers; draft-7: combined `RateLimit` header
legacyHeaders: false, // Disable the `X-RateLimit-*` headers.
// store: ... , // Redis, Memcached, etc. See below.
})
// Apply the rate limiting middleware to all requests.
app.use(limiter)
```
### Data Stores
The rate limiter comes with a built-in memory store, and supports a variety of
[external data stores](https://express-rate-limit.mintlify.app/reference/stores).
### Configuration
All function options may be async. Click the name for additional info and
default values.
| Option | Type | Remarks |
| ------------------------------------------------------------------------------------------------------------------ | -------------------------------- | ----------------------------------------------------------------------------------------------- |
| [`windowMs`](https://express-rate-limit.mintlify.app/reference/configuration#windowms) | `number` | How long to remember requests for, in milliseconds. |
| [`limit`](https://express-rate-limit.mintlify.app/reference/configuration#limit) | `number` \| `function` | How many requests to allow. |
| [`message`](https://express-rate-limit.mintlify.app/reference/configuration#message) | `string` \| `json` \| `function` | Response to return after limit is reached. |
| [`statusCode`](https://express-rate-limit.mintlify.app/reference/configuration#statuscode) | `number` | HTTP status code after limit is reached (default is 429). |
| [`legacyHeaders`](https://express-rate-limit.mintlify.app/reference/configuration#legacyheaders) | `boolean` | Enable the `X-Rate-Limit` header. |
| [`standardHeaders`](https://express-rate-limit.mintlify.app/reference/configuration#standardheaders) | `'draft-6'` \| `'draft-7'` | Enable the `Ratelimit` header. |
| [`requestPropertyName`](https://express-rate-limit.mintlify.app/reference/configuration#requestpropertyname) | `string` | Add rate limit info to the `req` object. |
| [`skipFailedRequests`](https://express-rate-limit.mintlify.app/reference/configuration#skipfailedrequests) | `boolean` | Uncount 4xx/5xx responses. |
| [`skipSuccessfulRequests`](https://express-rate-limit.mintlify.app/reference/configuration#skipsuccessfulrequests) | `boolean` | Uncount 1xx/2xx/3xx responses. |
| [`keyGenerator`](https://express-rate-limit.mintlify.app/reference/configuration#keygenerator) | `function` | Identify users (defaults to IP address). |
| [`handler`](https://express-rate-limit.mintlify.app/reference/configuration#handler) | `function` | Function to run after limit is reached (overrides `message` and `statusCode` settings, if set). |
| [`skip`](https://express-rate-limit.mintlify.app/reference/configuration#skip) | `function` | Return `true` to bypass the limiter for the given request. |
| [`requestWasSuccessful`](https://express-rate-limit.mintlify.app/reference/configuration#requestwassuccessful) | `function` | Used by `skipFailedRequests` and `skipSuccessfulRequests`. |
| [`validate`](https://express-rate-limit.mintlify.app/reference/configuration#validate) | `boolean` \| `object` | Enable or disable built-in validation checks. |
| [`store`](https://express-rate-limit.mintlify.app/reference/configuration#store) | `Store` | Use a custom store to share hit counts across multiple nodes. |
## Thank You
Sponsored by [Zuplo](https://zuplo.link/express-rate-limit) a fully-managed API
Gateway for developers. Add
[dynamic rate-limiting](https://zuplo.link/dynamic-rate-limiting),
authentication and more to any API in minutes. Learn more at
[zuplo.com](https://zuplo.link/express-rate-limit)
---
Thanks to Mintlify for hosting the documentation at
[express-rate-limit.mintlify.app](https://express-rate-limit.mintlify.app)
