The server sends a WebSocket ping frame every 30 seconds. The client must reply with a pong frame; if no pong is received within 10 seconds, the server disconnects the connection. Ping/pong are transport-level frames, not application (JSON) messages. Many client libraries respond to ping automatically. See Connection Management for details.
The public mainnet endpoint allows 32 trading actions/second per connection, with a 96-action burst per connection, 15 concurrent connections per IP, and 45 new connection attempts/minute per IP. Trading-action limits are not outbound market-data message limits.See Public API Rate Limits for shared-IP budgets and retry behavior.