AWS Bedrock Error: 'ReadTimeoutError' When Calling AWS Bedrock

#aws#bedrock#devops#cloud

A diagnostic guide to resolving AWS Bedrock inference failures caused by client-side read timeouts.

Problem

An AWS Bedrock invocation fails with a read timeout error.

Typical symptoms:

• Python (Boto3 / Botocore): ReadTimeoutError
• Node.js: Request hangs, then fails with a timeout
• General: Connection succeeds, but no response is returned before the timeout expires

Inference may have started, but the caller aborts the request.

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Clarifying the Issue

This is not an IAM issue.
This is not a client mismatch issue.

📌 This error occurs when Bedrock takes longer to return a response than the client’s read timeout allows.

📌 A read timeout happens after the connection is established, while waiting for inference output.

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Why It Matters

ReadTimeoutError is common when:

• Prompts or outputs are large
• High-latency models are used
• Streaming is disabled for long responses
• Default SDK timeout settings are left unchanged
• The environment is under load (Lambda, CI runners)

The request reaches Bedrock successfully—but the client stops waiting.

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Key Terms

• Read timeout – Maximum time a client waits for a response
• Inference latency – Time spent generating model output
• Client timeout – SDK-enforced request limit
• Streaming – Receiving inference output incrementally

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Steps at a Glance

1. Confirm the error is a read timeout
2. Check client-side timeout settings
3. Evaluate prompt and output size
4. Consider streaming responses
5. Retest the invocation

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Detailed Steps

1. Confirm the Error Type

Verify the error message explicitly references a read timeout, not a connection failure.

• Read timeout → connection established, response delayed
• Connect timeout → network or routing issue (handled separately)

This article applies only to read timeouts.

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2. Check Client Timeout Configuration

Most SDKs enforce conservative default timeouts.

Python (Boto3 / Botocore)

Boto3 uses Botocore’s default read timeout.

If inference is slow, increase it:

import boto3
from botocore.config import Config

config = Config(
    read_timeout=120,
    connect_timeout=10
)

client = boto3.client(
    "bedrock-runtime",
    config=config
)

Ensure the read timeout exceeds expected inference duration.

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Node.js (AWS SDK v3)

Verify HTTP handler timeout settings.

If unset, defaults may be too low for large inference requests.

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3. Evaluate Prompt and Output Size

Long inference time is often caused by:

• Large prompts
• Long conversation history
• High max_tokens values
• Large structured inputs (JSON, documents)

Mitigations:

• Reduce prompt size
• Trim context
• Lower output token limits
• Chunk large inputs

Inference time scales with token volume.

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4. Consider Streaming Responses

Streaming reduces perceived latency by returning output incrementally.

If supported by the model:

• Enable streaming APIs
• Consume streamed chunks immediately
• Avoid waiting for full output before reading

Non-streaming calls block until completion, increasing timeout risk.

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5. Retest the Invocation

After adjusting:

• Client read timeout
• Prompt size
• Output limits
• Streaming behavior

Retry the Bedrock call.

If the error disappears, the root cause was client-side timeout, not Bedrock availability.

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Pro Tips

• Read timeouts are client failures, not service failures
• Default SDK settings are often too low for inference
• Larger prompts mean slower responses
• Streaming trades simplicity for responsiveness
• Always tune timeouts based on real inference duration

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Conclusion

ReadTimeoutError occurs when the client stops waiting before Bedrock finishes responding.

Once:

• Client read timeouts are increased
• Payload size is controlled
• Streaming is used appropriately

AWS Bedrock inference completes successfully.

Increase the timeout.
Reduce the payload.
Then retry.

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Aaron Rose is a software engineer and technology writer at tech-reader.blog and the author of Think Like a Genius.