feat(rate-limiter): implement fixed window rate limiting algorithm

[halvaradop]

Description

This pull request implements the Fixed Window rate-limiting algorithm.

The algorithm can be used through the centralized createRateLimiter API or directly via the dedicated createFixedWindowAlgorithm function. This provides a simple and efficient rate-limiting strategy based on a fixed time window, where requests are counted and reset when the configured window expires.

Usage with createRateLimiter

import {
  createRateLimiter,
  createMemoryStorage,
} from "@aura-stack/rate-limiter"

const limiter = createRateLimiter({
  storage: createMemoryStorage(),
  rules: {
    signIn: {
      algorithm: "fixed-window",
      limit: 10,
      windowMs: 60_000,
      keyGenerator: (req: Request) =>
        req.headers.get("x-forwarded-for") ?? "unknown",
    },
  },
})

await limiter.signIn.check(
  new Request("http://incoming.request")
)

Direct Usage

import {
  createFixedWindowAlgorithm,
  createMemoryStorage,
} from "@aura-stack/rate-limiter"

const signInLimiter = createFixedWindowAlgorithm({
  algorithm: "fixed-window",
  limit: 10,
  windowMs: 60_000,
  storage: createMemoryStorage(),
  keyGenerator: (req: Request) =>
    req.headers.get("x-forwarded-for") ?? "unknown",
})

await signInLimiter.check(
  new Request("http://incoming.request")
)

Features

• Fixed Window rate-limiting algorithm
• Integration with createRateLimiter
• Direct usage through createFixedWindowAlgorithm
• Compatible with all supported storage adapters
• Custom request key generation
• Configurable request limits and time windows

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
auth	Skipped		Jun 10, 2026 8:05pm

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

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Run ID: bb4c1d94-2266-4240-9595-45fd25aca508

📥 Commits

Reviewing files that changed from the base of the PR and between e972b57 and 14617b6.

📒 Files selected for processing (6)

• packages/rate-limiter/CHANGELOG.md
• packages/rate-limiter/src/algorithms/fixed-window.ts
• packages/rate-limiter/src/algorithms/index.ts
• packages/rate-limiter/src/types.ts
• packages/rate-limiter/test/algorithms/fixed-window.test.ts
• packages/rate-limiter/test/algorithms/token-bucket.test.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/add-fixed-window-alg

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