Relay uses UTF-8 newline-delimited JSON over TCP on port 7400. Each line is one complete request or response. LinesCodec handles partial reads, combined reads, and framing; lines over 1 MiB are rejected. One connection may carry sequential requests. Idle reads time out after 30 seconds.
Requests are tagged by type:
{"type":"submit","job":{"queue":"email","payload":{"user_id":42},"priority":"high","max_attempts":5,"delay_ms":0,"retry_policy":{"kind":"exponential","base_ms":1000,"max_delay_ms":60000,"jitter":true}}}
{"type":"lease","worker_id":"worker_7","queues":["email"],"lease_ms":30000}
{"type":"renew","job_id":"job_...","worker_id":"worker_7","lease_token":"...","lease_ms":30000}
{"type":"ack","job_id":"job_...","worker_id":"worker_7","lease_token":"..."}
{"type":"fail","job_id":"job_...","worker_id":"worker_7","lease_token":"...","error":"timeout"}A lease returns {"type":"job","job":{...},"lease_token":"..."} or {"type":"no_job"}. Mutations return {"type":"ok"}. Errors are structured as {"type":"error","code":"stale_lease","message":"..."}. Stable error codes are malformed_request, invalid, not_found, stale_lease, and internal.
Malformed data affects only its connection. Queue names, subscription counts, payloads, frames, errors, lease durations, and connections are bounded. The protocol is currently unauthenticated and intended for a trusted private network.