View the Docker build output for any environment deployed from source code. Build logs help you debug failed deployments by showing exactly which step failed.
Accessing Build Logs
In the dashboard, click the build log button (document icon) in the Actions column for any environment with status running, starting, or failed.
A modal opens with the full build output — the same output you'd see running docker build locally.
What's Included
The build log captures:
- Base image pull progress
- Package installation (
npm install,pip install, etc.) - Build steps (
npm run build,go build, etc.) - Any errors or warnings during the build
- The final image creation step
Log Size
Build logs are truncated to the last 50 KB to avoid storing excessively large outputs. For most projects, this captures the complete build. For very large builds, you'll see the most recent (and most relevant) portion.
Availability
Build logs are available for environments deployed from source code (local directory, Git, FTP, SSH). Environments deployed from pre-built Docker images (--image) do not have build logs since no build step occurs.
Debugging Failed Deploys
When an environment shows status failed, the build log is the first place to check. Common issues:
- Missing dependencies — Check if
package.jsonorrequirements.txtis complete - Build script errors — Verify your build command works locally
- Port mismatch — Ensure your app listens on the expected port
- Memory limits — Large builds may exceed container memory during compilation