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Anthropic Claude API error

Anthropic API 429 rate_limit_error: what it means and how to fix it

Error message
429 rate_limit_error

Retry? YesLast verified 3 documented fixes3 sources

What it means

Your organization has hit a rate limit. The 429 error describes which rate limit was exceeded, and when the response has a retry-after header you should wait that many seconds before retrying. Fast mode rate limits also return a 429 with a retry-after header.

Causes

  • Exceeding an organization rate limit
  • Exceeding fast mode rate limits
  • Claude Code requests over the Claude Code workspace spend limit (these 429s carry a retry-after header)

How to fix it

  1. Fix 1.

    When the response has a retry-after header, wait that many seconds before retrying.

  2. Fix 2.

    The official SDK automatically retries rate limits with exponential backoff, twice by default, honoring the retry-after header when present. Configure or disable this with max_retries.

    Snippet
    client = Anthropic(
    max_retries=0,  # default is 2
)
  3. Fix 3.

    Request higher limits by moving to a higher usage tier.

Seen in coding agents

These coding agent messages pass this Anthropic API error through. Each page has the agent-specific fix.

More Anthropic API errors

All 13 Anthropic API errors

HTTP 429 at other providers

Compare 429 across providers

FAQ

What does the Anthropic API error "429 rate_limit_error" mean?

Your organization has hit a rate limit. The 429 error describes which rate limit was exceeded, and when the response has a retry-after header you should wait that many seconds before retrying. Fast mode rate limits also return a 429 with a retry-after header.

How do I fix Anthropic API "429 rate_limit_error"?

There are 3 documented fixes. Start with the first: When the response has a retry-after header, wait that many seconds before retrying.

Should I retry Anthropic API "429 rate_limit_error"?

Yes. The official docs treat this error as retryable.

Which other AI APIs return HTTP 429?

Per their official error docs: Amazon Bedrock (429 ThrottlingException; 429 ModelNotReadyException), Azure OpenAI (429 Too Many Requests (Rate limit is exceeded); 429 Too Many Requests (System is experiencing high demand); 429 Too Many Requests (temporary rate limit adjustment); 429 Too Many Requests (token budget exceeded by request parameters)), Cohere API (429 Too Many Requests), DeepSeek API (429 - Rate Limit Reached), Gemini API (429 rate_limit_exceeded; 429 quota_exceeded; 429 too_many_requests; 429 RESOURCE_EXHAUSTED), Groq API (429 Too Many Requests), Mistral API (429 Too many requests), OpenAI API (429 credit_balance_exhausted; 429 Rate limit reached for requests; 429 rate_limit_error slow_down; 429 organization_spend_limit_exceeded; 429 project_spend_limit_exceeded; 429 organization_usage_limit_exceeded), OpenRouter (429 rate_limit_exceeded), Vertex AI (429 RESOURCE_EXHAUSTED; 429 Resource exhausted, please try again later; 429 Too many requests. Exceeded the Provisioned Throughput), xAI API (429 Too Many Requests).

Sources

Last verified against 3 sources: Anthropic API's official docs and official SDK repositories.

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