Changelog

All notable user-facing changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

8.1.0

Fixed

• RateLimit-Reset is now always set when standardHeaders is set to 'draft-6' and the store supports it.

Added

• New windowMs validation check that ensures it’s in the valid range when using the built-in Memory store.
• New forwardedHeader validation check to warn when the Forwarded header is present but ignored.

8.0.1

Fixed

• ipKeyGenerator function is now correctly exported in CommonJS build
• express’s Request and Response types are once again correctly referenced in .d.ts files

Changed

• Replaced ip library with ip-address due to a vulnerability in ip.

  Note that express-rate-limit did not use the vulnerable code path, but we swapped the library to prevent users from getting vulnerability warnings and reports.

8.0.0

Breaking

• IPv6 addresses are now masked with a /56 subnet by default. For example, the following two IP addresses will now be considered to be the same user and grouped together for rate-limiting:

  • 0123:4567:89ab:cd11:1111:1111:1111:1111
  • 0123:4567:89ab:cd22:2222:2222:2222:2222

  (both would be normalized to 123:4567:89ab:cd00::/56)

Fixed

• Fixed a vulnerability where IPv6 users could bypass rate limiting by iterating through multiple IP addresses in their ISP-assigned subnet.

Added

• ipv6Subnet configuration option used by the default keyGenerator, defaults to 56
• ipKeyGenerator(ip, ipv6Subnet) helper method to apply the desired subnet to IPv6 addresses (returns IPv4 unchanged)
• ipv6Subnet validation check on above configuration option’s value (allowed range is 32-64)
• ipv6SubnetOrKeyGenerator validation check to warn of an incompatible combination of ipv6Subnet and keyGenerator settings.
• keyGeneratorIpFallback validation check on custom keyGenerators to ensure they’re using ipKeyGenerator if they reference req.ip or request.ip

7.5.1

Changed

• Narrowed type of standardHeaders from string to just the supported values via a TypeScript const assertion (#506)

7.5.0

Added

• Implemented the combined RateLimit header according to the eighth draft of the IETF RateLimit header specification. Enable by setting standardHeaders: 'draft-8'.
• Added a new identifier option, used as the name for the quota policy in the draft-8 headers.
• Added a new headersDraftVersion validation check to identifies cases where an unsupported version string is passed to the standardHeaders option.

7.4.1

Fixed

• Made the passOnStoreError return after calling next() rather than continuing execution.

7.4.0

Added

• Added passOnStoreError option to allow a way to “fail open” in the event of a backend error.

7.3.1

Fixed

• Changed error displayed for the creationStack validation check when a store with localKeys set to false is used.
• Improved documentation for the creationStack check.

7.3.0

Added

• Added a new unsharedStore validation check that identifies cases where a single store instance is shared across multiple limiters.

7.2.0

Added

• Added a new creationStack validation check that looks for instances created in a request handler.

7.1.5

Fixed

• Enable async requestWasSuccessful methods to work as documented.

7.1.4

Fixed

• Ensure header values are strings rather than numbers, for compatibility with Bun.

7.1.3

Changed

• Loosened peer dependencies to explicitly allow the Express 5 beta. (See #415)

7.1.2

Changed

• Re-organized documentation from readme into docs/ folder and added documentation website.

v7.1.1

Added

• Enabled provenance statement generation, see https://github.com/express-rate-limit/express-rate-limit#406.

7.1.0

Changed

• The getKey method is now always defined. If the store does not have the required get method, getKey will throw an error explaining this.

7.0.2

Added

• Added cluster-memory-store to the readme and made a couple of other minor clarifications.

7.0.1

Added

• Added rate-limit-postgresql to the stores list in the readme.

7.0.0

Breaking

• Changed behavior when max is set to 0:
  • Previously, max: 0 was treated as a ‘disable’ flag and would allow all requests through.
  • Starting with v7, all requests will be blocked when max is set to 0.
  • To replicate the old behavior, use the skip function instead.
• Renamed req.rateLimit.current to req.rateLimit.used.
  • current is now a hidden getter that will return the used value, but it will not appear when iterating over the keys or calling JSON.stringify().
• Changed the minimum required Node version from v14 to v16.
  • express-rate-limit now targets es2022 in TypeScript/ESBuild.
• Bumped TypeScript from v4 to v5 and dts-bundle-generator from v7 to v8.

Deprecated

• Removed the draft_polli_ratelimit_headers option (it was deprecated in v6).
  • Use standardHeaders: 'draft-6' instead.
• Removed the onLimitReached option (it was deprecated in v6).
  • This is an example of how to replicate it’s behavior with a custom handler option.

Changed

• The MemoryStore now uses precise, per-user reset times rather than a global window that resets all users at once.
• The limit configuration option is now preferred to max.
  • It still shows the same behavior, and max is still supported. The change was made to better align with terminology used in the IETF standard drafts.

Added

• The validate config option can now be an object with keys to enable or disable specific validation checks. For more information, see this.

6.11.2

Fixed

• Restored IncrementResponse TypeScript type (See #397)

6.11.1

Fixed

• Check for prefixed keys when validating that the stores have single counted keys (See #395).

6.11.0

Added

• Support for retrieving the current hit count and reset time for a given key from a store (See #390).

6.10.0

Added

• Support for combined RateLimit header from the RateLimit header fields for HTTP standardization draft adopted by the IETF. Enable by setting standardHeaders: 'draft-7'.
• New standardHeaders: 'draft-6' option, treated equivalent to standardHeaders: true from previous releases. Note that true and false are still supported.
• New RateLimit-Policy header added when standardHeaders is set to 'draft-6', 'draft-7', or true.
• Warning when using deprecated draft_polli_ratelimit_headers option.
• Warning when using deprecated onLimitReached option.
• Warning when totalHits value returned from Store is invalid.

6.9.0

Added

• New validaion check for double-counted requests.
• Added help link to each validation error, directing users to the appropriate wiki page for more info.

Changed

• Miscellaneous documentation improvements.

6.8.1 & 6.7.2

Changed

• Revert 6.7.1 change that bumped typescript from 5.x to 4.x and dts-bundle-generator from 8.x to 7.x (See #360).

6.8.0

Added

• Added a set of validation checks that will log an error if failed. See https://github.com/express-rate-limit/express-rate-limit/wiki/Error-Codes for a list of potential errors. Can be disabled by setting validate: false in the configuration. Automatically disables after the first request. (See #358).

6.7.1

Fixed

• Fixed compatibility with TypeScript’s TypeScript new node16 module resolution strategy (See #355).

Changed

• Bumped development dependencies
  • This initially include bumping typescript from 4.x to 5.x and dts-bundle-generator from 7.x to 8.x
• Added node 20 to list of versions the CI jobs run on.

No functional changes.

6.7.0

Changed

• Updated links to point to the new express-rate-limit organization on GitHub.
• Added advertisement to readme.md for project sponsor Zuplo.
• Updated to typescript version 5 and bumped other dependencies.
• Dropped node 12, and added node 19 to the list of versions the CI jobs run on.

No functional changes.

6.6.0

Added

• Added shutdown method to the Store interface and the MemoryStore.

6.5.2

Fixed

• Fixed an issue with missing types in ESM monorepos.

6.5.1

Added

• The message option can now be a (sync/asynx) function that returns a value (#311)

Changed

• Updated all dependencies

Note: 6.5.0 was not released due to CI automation issues.

6.4.0

Added

• Adds Express 5 (5.0.0-beta.1) as a supported peer dependency (#304)

Changed

• Tests are now run on Node 12, 14, 16 and 18 on CI (#305)
• Updated all development dependencies (#306)

6.3.0

Changed

• Changes the build target to es2019 so that ESBuild outputs code that can run with Node 12.
• Changes the minimum required Node version to 12.9.0.

6.2.1

Fixed

• Use the default value for an option when undefined is passed to the rate limiter.

6.2.0

Added

• Export the MemoryStore, so it can now be imported as a named import (import { MemoryStore } from 'express-rate-limit').

Fixed

• Deprecate the onLimitReached option (this was supposed to be deprecated in v6.0.0 itself); developers should use a custom handler function that checks if the rate limit has been exceeded instead.

6.1.0

Added

• Added a named export rateLimit in case the default import does not work.

Fixed

• Added a named export default, so Typescript CommonJS developers can default-import the library (import rateLimit from 'express-rate-limit').

6.0.5

Fixed

• Use named imports for ExpressJS types so users do not need to enable the esModuleInterop flag in their Typescript compiler configuration.

6.0.4

Fixed

• Upload the built package as a .tgz to GitHub releases.

Changed

• Add main and module fields to package.json. This helps tools such as ESLint that do not yet support the exports field.
• Bumped the minimum node.js version in package-lock.json to match package.json

6.0.3

Changed

• Bumped minimum Node version from 12.9 to 14.5 in package.json because the transpiled output uses the nullish coalescing operator (??), which isn’t supported in node.js prior to 14.x.

6.0.2

Fixed

• Ensure CommonJS projects can import the module.

Added

• Add additional tests that test:
  • importing the library in js-cjs, js-esm, ts-cjs, ts-esm environments.
  • usage of the library with external stores (redis, mongo, memcached, precise).

Changed

• Use esbuild to generate ESM and CJS output. This reduces the size of the built package from 138 kb to 13kb and build time to 4 ms! :rocket:
• Use dts-bundle-generator to generate a single Typescript declaration file.

6.0.1

Fixed

• Ensure CommonJS projects can import the module.

6.0.0

Added

• express 4.x as a peer dependency.
• Better Typescript support (the library was rewritten in Typescript).
• Export the package as both ESM and CJS.
• Publish the built package (.tgz file) on GitHub releases as well as the npm registry.
• Issue and PR templates.
• A contributing guide.

Changed

• Rename the draft_polli_ratelimit_headers option to standardHeaders.
• Rename the headers option to legacyHeaders.
• Retry-After header is now sent if either legacyHeaders or standardHeaders is set.
• Allow keyGenerator to be an async function/return a promise.
• Change the way custom stores are defined.
  • Add the init method for stores to set themselves up using options passed to the middleware.
  • Rename the incr method to increment.
  • Allow the increment, decrement, resetKey and resetAll methods to return a promise.
  • Old stores will automatically be promisified and used.
• The package can now only be used with NodeJS version 12.9.0 or greater.
• The onLimitReached configuration option is now deprecated. Replace it with a custom handler that checks the number of hits.

Removed

• Remove the deprecated limiter.resetIp method (use the limiter.resetKey method instead).
• Remove the deprecated options delayMs, delayAfter (the delay functionality was moved to the express-slow-down package) and global (use a key generator that returns a constant value).

5.x

Added

• The middleware throws logs an error if request.ip is undefined.

Removed

• Removes typescript typings. (See #138)

4.x

Changed

• The library no longer modifies the passed-in options object, it instead makes a clone of it.

3.x

Added

• Simplifies the default handler function so that it no longer changes the response format. The default handler also uses response.send.

Changes

• onLimitReached now only triggers once for a client and window. However, the handle method is called for every blocked request.

Removed

• The delayAfter and delayMs options; they were moved to the express-slow-down package.

2.x

Added

• Support external stores (from version 2.3.0) onwards.
• A limiter.resetKey() method to reset the hit counter for a particular client

Changes

• The rate limiter now uses a less precise but less resource intensive method of tracking hits from a client.

Removed

• The global option.