# Lambda shows no Datadog data layer, env vars, site
What you see: the function runs, CloudWatch has logs, but Serverless Functions in Datadog shows nothing.
## Checklist
1. **Layer attached?** Open the function config, Layers section. The Datadog extension layer must be listed. If someone deployed without it, there is no telemetry, period.
2. **Right region in the ARN?** The layer ARN embeds the region (`arn:aws:lambda:[region]:464622532012:layer:Datadog-Extension:[version]`). Copy-pasting an ARN from another region fails silently.
3. **Current layer version?** Old versions have known issues. Use the latest from the docs.
4. **DD_API_KEY set?** The function env must have it (via Secrets Manager in prod). Empty or placeholder means the extension cannot authenticate.
5. **DD_SITE set?** Non-US1 orgs need it on the function too, same trap as everywhere.
6. **DD_TRACE_ENABLED / DD_LOGS_ENABLED.** Metrics flow by default with the extension; traces and logs need their flags.
7. **Enhanced metrics need the forwarder?** No: enhanced Lambda metrics come through the extension. But log shipping from CloudWatch log groups still needs the forwarder subscription.
## Confirm
Invoke the function, wait a minute, check Serverless, Functions. If invocations appear but not traces, the tracer library is missing from your deployment package: the extension does not instrument code by itself.
## Trap
Attaching only the forwarder subscription and expecting metrics and traces. The forwarder ships logs; telemetry needs the extension layer.