AWS Lambda 'Task timed out after 3.00 seconds' (or X seconds). How do I fix function timeouts?

Cause: Lambda stops an invocation when it runs longer than the function's configured timeout. The default is 3 seconds, and it can be raised in 1-second steps up to 900 seconds (15 minutes) for standard functions. If the timeout is close to the function's normal duration, it will fail intermittently. AWS lists typical causes: S3 downloads that are larger or slower than usual, a call to another service that responds slowly, or input that needs more computation than your tests used. The message can also appear when the Init phase (module loading, client setup) times out; Lambda then re-runs Init on the next request (a suppressed init), which may not leave enough time for the handler, especially with the 3-second default. Fix: 1. Raise the timeout to something realistic. CLI: aws lambda update-function-configuration --function-name my-function --timeout 120. In SAM use the Timeout property under the function, then deploy. Do not just set the maximum; pick a value above your observed worst-case duration. 2. Increase memory. More memory also gives proportionally more CPU, which often shortens both Init and Invoke phases. 3. Reduce initialization work: create SDK clients and load large modules once outside the handler, and trim unneeded dependencies. 4. Find the slow step. Log timestamps around downstream calls, check CloudWatch Logs REPORT lines for Duration and Max Memory Used, and set client-side timeouts on HTTP and SDK calls so a hung dependency fails fast with a useful error instead of consuming the whole invocation. 5. Test with realistic data sizes (upper bounds of what you expect), not tiny samples. 6. If the function sits in a VPC and calls the internet or AWS APIs, confirm it has a route (NAT gateway or VPC endpoints); a blocked network path looks like a timeout. 7. For long-running work, split it into smaller units, use a queue or Step Functions, or run it on a service built for long jobs. Verify: invoke with a realistic payload and confirm the REPORT line shows Duration comfortably below the new timeout, with no timeout messages in the logs over a representative period. Sources: https://docs.aws.amazon.com/lambda/latest/dg/configuration-timeout.html https://docs.aws.amazon.com/lambda/latest/dg/troubleshooting-invocation.html