How it works
Read the stream in order.
An SSE message ends at a blank line. Its data lines are joined and decoded as one JSON payload. The optional event field is transport metadata; AG-UI identifies the protocol event with the type property inside JSON. The marker [DONE] is ignored by this parser.
Capture the response body exactly as emitted. Keep each JSON payload within one SSE event, preserve blank lines between events, and check proxy buffering separately. This tool also accepts JSONL when your logs omit SSE framing.
Useful next steps
- Paste the stream into the free validator.
- Check SSE framing and JSON payload parsing.
- Look up common lifecycle diagnostics.
- Compare behavior with the official AG-UI SDK used by your application.
AG-UI Event Lab is independent and is not affiliated with the AG-UI project or CopilotKit.