{
  "id": "art_TjlR8Ly_7t7P",
  "slug": "openai-api-rate-limit-troubleshooting-from-http-429-to-exponential-backoff",
  "author": "goumang",
  "title": "OpenAI API Rate Limit Troubleshooting: From HTTP 429 to Exponential Backoff",
  "summary": "This article provides detailed guidance on OpenAI API 429 errors (TPM/RPM limits), implementing retry with exponential backoff, and multi-API-key rotation for building robust LLM applications.",
  "content": "# Overview\n\nOpenAI API Rate Limits restrict the number of requests and tokens per time period. When exceeded, the API returns 429 errors. This article covers error causes, troubleshooting, and retry strategies.\n\n## Rate Limit Types\n\n| Type | Description | Org Limits |\n|------|-------------|------------|\n| RPM | Requests per Minute | Usually 200-500 |\n| TPM | Tokens per Minute | Usually 60K-120K |\n| RPD | Requests per Day | By subscription |\n\n## Identifying Rate Limit Errors\n\n```python\nimport openai\n\ntry:\n    response = openai.ChatCompletion.create(\n        model=\"gpt-4\",\n        messages=[{\"role\": \"user\", \"content\": \"Hello\"}]\n    )\nexcept openai.error.RateLimitError as e:\n    print(f\"Rate Limit Error: {e}\")\n```\n\n## Exponential Backoff Retry\n\n```python\nfrom tenacity import retry, stop_after_attempt, wait_exponential\n\n@retry(\n    stop=stop_after_attempt(5),\n    wait=wait_exponential(multiplier=1, min=2, max=60)\n)\ndef call_with_retry(messages):\n    return openai.ChatCompletion.create(\n        model=\"gpt-4\",\n        messages=messages\n    )\n```\n\n## Multi-Key Rotation\n\n```python\nAPI_KEYS = [\"key1\", \"key2\", \"key3\"]\ncurrent_key_index = 0\n\ndef call_with_rotation(messages):\n    global current_key_index\n    for _ in range(len(API_KEYS)):\n        openai.api_key = API_KEYS[current_key_index]\n        try:\n            return openai.ChatCompletion.create(messages=messages)\n        except openai.error.RateLimitError:\n            current_key_index = (current_key_index + 1) % len(API_KEYS)\n    raise Exception(\"All keys exhausted\")\n```\n\n## Prevention\n\n1. **Request Batching**: Merge multiple small requests\n2. **Response Caching**: Cache similar requests\n3. **Rate Limiting Middleware**: TokenBucket or LeakyBucket\n4. **Monitoring**: Set TPM usage alerts\n\n## References\n\n- [OpenAI Rate Limits](https://platform.openai.com/docs/guides/rate-limits)\n- [Tenacity Library](https://tenacity.readthedocs.io/en/latest/)\n",
  "lang": "en",
  "domain": "error_codes",
  "tags": [
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    "rate-limit",
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    "api-key"
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  "keywords": [
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    "TPM/RPM"
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