4xx Client Error

HTTP 429 Too Many Requests

The user has sent too many requests in a given amount of time (rate limiting). The response may include a Retry-After header indicating how long to wait before making new requests.

Common Causes

  • API rate limit exceeded (too many calls per minute/hour)
  • Brute-force login attempts triggering throttling
  • Automated scraping hitting the server too frequently
  • Shared API key used by too many clients simultaneously

How to Fix

  1. 1Check the Retry-After header and wait before retrying
  2. 2Implement exponential backoff in your retry logic
  3. 3Reduce request frequency or batch multiple requests
  4. 4Upgrade your API plan for higher rate limits

Example

HTTP 429 Too Many Requests
GET /api/data HTTP/1.1

→ 429 Too Many Requests
→ Retry-After: 60
→ "Rate limit: 100 requests per minute"

Related Client Error Codes

400

Bad Request

401

Unauthorized

402

Payment Required

403

Forbidden

404

Not Found

405

Method Not Allowed

406

Not Acceptable

407

Proxy Authentication Required

408

Request Timeout

409

Conflict

410

Gone

411

Length Required

412

Precondition Failed

413

Content Too Large

414

URI Too Long

415

Unsupported Media Type

416

Range Not Satisfiable

417

Expectation Failed

418

I'm a Teapot

421

Misdirected Request

422

Unprocessable Content

423

Locked

424

Failed Dependency

425

Too Early

426

Upgrade Required

428

Precondition Required

431

Request Header Fields Too Large

451

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