OpenPrinterOpenPrinter Agent Gateway
Server sends heartbeat
The server periodically sends a heartbeat with a response deadline. If
the correlated agent.heartbeat is not received in time, the server
closes the session and may reconnect according to its retry policy.
Address
/.well-known/openprinter/gatewayDescription
The authenticated, bidirectional OPPA gateway socket.
Messages
A liveness probe sent after the session is connected. The agent must
return an agent.heartbeat with this message's ID as its
correlationId before timeoutMs elapses.
Payload
Message Example
{ "protocolVersion": "1", "messageId": "heartbeat_01", "sentAt": "2026-08-21T00:00:30Z", "type": "server.heartbeat", "payload": { "timeoutMs": 120000 }}