Comparison of WebSocket implementations

Comparison of WebSocket Implementations

Rationale

The WebSocket protocol is implemented in different browsers, run-time environments and libraries acting as clients or servers. The intention of this comparison is to show different features of WebSocket implementations to help developers and users making informed decisions regarding deployment and use.

Table of WebSocket implementations

	cwebsocket	Mozilla Firefox 7	Mozilla Firefox 8	Jetty	UnittWebSocket	libwebsockets	apache-websocket	pywebsocket	WebSocket-Node	ws4py	The Server Framework	WebSocket++
Project Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage	Homepage
Client (library)	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	No	No	Yes	Yes (Threaded and Tornado)	Yes	Yes
Server (library)	Yes	No	Yes	No	No	Yes	No	Yes	Yes (For Apache HTTPD web server)	Yes	Yes	Yes (CherryPy)	Yes	Yes
Version compared	0.4.3 30 Oct 2011	15.0.874.8 12 Sep 2011	r32 29 Aug 2010	7 beta 12 Sep 2011	8.0a/9.0a 12 Sep 2011	7.5.1 9 Sep 2011	0.9.4/0.9.2 29 Sep 2011	? 24 Aug 2011	? 29 Oct 2011	0.6b5 30 Aug 2011	v0.0.13 18 Aug 2011	0.1.1 21 Aug 2011	v6.5 5 Sep 2011	2010-10-10 10 Oct 2011
Protocol (Spec) version support	8, 13 (10-17)	8 (10)	Hixie 76 (0)	8 (10)	8 (10)	0-13 (0-13)[1]	Hixie 75/76, HyBi 7,8,10	8 (10)	draft 75/76 (Hixie), 7,8,13 (HyBi) [1]	8 (12)	8 (10)	8 (10)	Hixie 76, HyBi 7,8,13	7,8,13 (17)
Protocol Test Report	Report (Client) Report (Server)	Report	[? Report]	Report	Report	JUnit Autobahn	[? Report]	[? Report]	[? Report]	[? Report]	Report	Report	Report	Report (Client) Report (Server)
License	Apache 2	complex	MIT	MPL & GPL & LGPL	MPL & GPL & LGPL	Apache 2 & EPL	Apache 2	LGPL (v2)	Apache 2	BSD	Apache 2	BSD	Commercial	BSD
Implementation language/environment	Python / Twisted	C++ / WebKit	C / Sockets	C++ / Necko	C++ / Necko	Java / J2SE & Android	Java / J2SE & Android & Objective-C & IOS	C / Sockets	C / Sockets	Python	JavaScript / Node.js	Python	C++ Windows IOCP	C++ / Boost Asio
API language/environment	Python / Twisted	JavaScript / HTML5	C	JavaScript / HTML5	JavaScript / HTML5	Java / javax.servlet	Java / J2SE & Android & Objective-C & IOS	C / own event loop[2]	C / Sockets	Python	JavaScript / Node.js	Python	C++ Windows	C++
Text Message support	Yes	Yes	?	Yes	Yes	Yes	Yes	Yes	?	?	Yes	Yes	Yes	Yes
Binary Message support	Yes	No	?	No	No	Yes	Yes	Yes	?	?	Yes	Yes	Yes	Yes
Message-based API	Yes	Yes	?	Yes	Yes	Yes	Yes	No [3]	?	?	Yes	Yes	Yes	Yes
Frame-based API	Yes	No	?	No	No	Yes	Yes	No [4]	?	?	Yes	Yes	Yes	No
Streaming API Input/Output	Yes/Yes [2]	No/No	?/?	No/No	No/No	No/No[5]	No/No[5]	Yes/Yes	?/?	?/?	No/No	No/No	Yes/Yes	No/No
Flow-control framework	Yes [3]	No	?	No	No	Yes[6]	Yes[6]	Yes	?	?	No	No	Yes[6]	Yes[6]
Automatic Pongs for Pings	Yes	Yes	?	Yes	Yes	Yes	Yes	Yes	?	?	Yes	Yes	Yes	Yes
Automatic Heartbeat Pings	No	No	?	No	No	No	No	No	?	?	Optional	No	No	No
Manual Pings/Pongs	Yes	No	?	No	No	Yes	Yes	Yes	?	?	Yes	Yes	Yes	Yes
Frame Size Limit	2^63 (streaming API) memory-limited/configurable (other APIs)	>=16MB (memory-limited?)	?	<16MB	<16MB	2^32 tx 2^63 rx	2^32 tx (configurable) 2^63 rx (configurable)	2^63	?	?	memory-limited, configurable	memory-limited	2^63 or configurable limit	memory-limited, configurable

Notes

1. ^ Server accepts 0-13, Client sends only 13.
2. ^ There is a low-level support for integration with external event loops.
3. ^ Users can build a message-based layer on top of the streaming API provided.
4. ^ Users can build a frame-based layer on top of the streaming API provided.
5. ^ ^{a b} Frames larger that the buffer are fragmented and passed to the message layer as a stream of smaller frames.
6. ^ ^{a b c d} Internal queuing is avoided so that natural TCP/IP backpressure is used for flow control. A slow application consuming messages will eventually block a busy sender.