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Protocols

Cloudflare Workers support the following protocols and interfaces:

ProtocolInboundOutbound
HTTP / HTTPSHandle incoming HTTP requests using the fetch() handlerMake HTTP subrequests using the fetch() API
Direct TCP socketsSupport for handling inbound TCP connections is coming soonCreate outbound TCP connections using the connect() API
WebSocketsAccept incoming WebSocket connections using the WebSocket API, or with MQTT over WebSockets (Pub/Sub)MQTT over WebSockets (Pub/Sub)
MQTTHandle incoming messages to an MQTT broker with Pub SubSupport for publishing MQTT messages to an MQTT topic is coming soon
HTTP/3 (QUIC)Accept inbound requests over HTTP/3 by enabling it on your zone in Speed > Optimization > Protocol Optimization area of the Cloudflare dashboard.
SMTPUse Email Workers to process and forward email, without having to manage TCP connections to SMTP email serversEmail Workers