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Amazon Bedrock (Runtime API) error

Amazon Bedrock 503 ServiceUnavailableException: what it means and how to fix it

Error message
503 ServiceUnavailableException

Retry? YesLast verified 4 documented fixes2 sources

What it means

The service is temporarily unable to handle the request because of high demand or temporary capacity constraints. This is not related to account-level quotas or rate limits, which return 429 ThrottlingException.

Causes

  • High demand on the service
  • Temporary capacity constraints

How to fix it

  1. Fix 1.

    Use retries with exponential backoff and random jitter.

  2. Fix 2.

    Switch to a different AWS Region if the issue persists, or use cross-Region inference to route requests across Regions.

  3. Fix 3.

    For predictable, sustained throughput, consider Reserved Tier or Provisioned Throughput where supported.

  4. Fix 4.

    Check the AWS Health Dashboard for announced issues or scheduled maintenance.

More Amazon Bedrock errors

All 22 Amazon Bedrock errors

HTTP 503 at other providers

Compare 503 across providers

FAQ

What does the Amazon Bedrock error "503 ServiceUnavailableException" mean?

The service is temporarily unable to handle the request because of high demand or temporary capacity constraints. This is not related to account-level quotas or rate limits, which return 429 ThrottlingException.

How do I fix Amazon Bedrock "503 ServiceUnavailableException"?

There are 4 documented fixes. Start with the first: Use retries with exponential backoff and random jitter.

Should I retry Amazon Bedrock "503 ServiceUnavailableException"?

Yes. The official docs treat this error as retryable.

Which other AI APIs return HTTP 503?

Per their official error docs: Azure OpenAI (503 Server Error), DeepSeek API (503 - Server Overloaded), Gemini API (503 service_unavailable; 503 UNAVAILABLE), Groq API (503 Service Unavailable), Mistral API (503 Service unavailable), OpenAI API (503 service_unavailable_error server_is_overloaded), OpenRouter (503 No available model provider meets your routing requirements; 503 provider_overloaded), Vertex AI (503 UNAVAILABLE).

Sources

Last verified against 2 sources: Amazon Bedrock's official docs and official SDK repositories.

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