Rate Limiting — Animate | AI Wisdom

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🎞 ANIMATE · Mode 3 of 5 · +100 XP— Token Bucket Rate Limiter
📋Request
⚙️Token Check
🔄Refill
✅Allow/Deny
🎯 Next: Test →
Step 1 / 4
Speed
Request arrives
API request received — check rate limit for user/IP💡 Analogy
Your bucket starts full of tokens. Each request spends one.
Each API request generates a rate limit check using a unique key (user ID or IP address).
Console Output
> new request: GET /api/data
> rate limit key: "ratelimit:user:1234"
> config: {capacity:100, refillRate:10/s}
●rate-limiter.ts
Request arrivesL10–13
1import { Redis } from 'ioredis';
2 
3const redis = new Redis();
4 
5interface RateLimitConfig {
6  capacity: number;    // Max tokens in bucket
7  refillRate: number;  // Tokens per second
8}
9 
10async function isAllowed(
11  key: string,
12  config: RateLimitConfig,
13): Promise<{ allowed: boolean; remaining: number }> {
14  const now = Date.now() / 1000;
15 
16  const script = `
17    local tokens = tonumber(redis.call('GET', KEYS[1]..'_tokens') or ARGV[1])
18    local lastRefill = tonumber(redis.call('GET', KEYS[1]..'_ts') or ARGV[4])
19    local elapsed = ARGV[4] - lastRefill
20    local refilled = math.min(ARGV[1], tokens + elapsed * ARGV[2])
21 
22    if refilled >= 1 then
23      redis.call('SET', KEYS[1]..'_tokens', refilled - 1, 'EX', 60)
24      redis.call('SET', KEYS[1]..'_ts', ARGV[4], 'EX', 60)
25      return {1, refilled - 1}
26    else
27      return {0, 0}
28    end
29  `;
30 
31  const [allowed, remaining] = await redis.eval(
32    script, 1, key,
33    config.capacity, config.refillRate,
34    1, now,
35  ) as [number, number];
36 
37  return { allowed: allowed === 1, remaining };
38}
38 lines
Timeline — 4 Steps
Request arrives
API request received — check rate limit for user/IP💡 Analogy
Your bucket starts full of tokens. Each request spends one.
Each API request generates a rate limit check using a unique key (user ID or IP address).
Console Output
> new request: GET /api/data
> rate limit key: "ratelimit:user:1234"
> config: {capacity:100, refillRate:10/s}

API request received — check rate limit for user/IP

API request received — check rate limit for user/IP

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API request received — check rate limit for user/IP

API request received — check rate limit for user/IP

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Discussion