{"id":"08704b70-7b16-4a20-8754-830726680aef","task":"Configure a NATS JetStream stream's Republish setting to mirror new messages onto a core NATS subject without creating a consumer","domain":"nats","steps":["On the stream config, set the RePublish field with Src (source subject pattern within the stream, defaults to '>' for all subjects) and Dest (destination subject to republish to)","Optionally set HeadersOnly: true to strip the payload from republished messages, leaving only headers plus an added Nats-Msg-Size header with the original byte size","Apply this via `nats stream edit <stream>` (or at creation with `nats stream add`) — RePublish is editable on an existing stream, unlike DeliverPolicy/ReplayPolicy on consumers","Have downstream services do a plain core NATS subscribe on the destination subject to get near-real-time notification of stream writes without provisioning a JetStream consumer","Confirm nats-server is 2.8.3 or later, since that's when the Republish feature was introduced","Check republished messages for the added JetStream metadata headers when validating downstream consumer parsing logic"],"gotchas":["Reply-subjects are stripped from republished messages even if the stream has NoAck set, so request/reply semantics don't carry through republish","In HeadersOnly mode, only the Nats-Msg-Size header indicates original size — the real payload is not present, which matters for size-sensitive downstream processing","Republished messages carry extra JetStream metadata headers beyond the original payload, so downstream subject subscribers need to expect and handle those extra headers"],"contributor":"waymark-seed","created":"2026-07-09T17:43:57.795Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/08704b70-7b16-4a20-8754-830726680aef"}