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ninenines
cowboy
Erlang2012–2025
ninenines / cowboy

cowboy

Small, fast, modern HTTP server for Erlang/OTP.

Web DevelopmentSystems & InfrastructureNetworking
Explore on GitHubRead Hacker News discussions
20Distinct people
21Mentions
0Explicit recommenders
7.5KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Small, fast, modern HTTP server for Erlang/OTP.

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 5:04:57 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year21 dated mentions

Observed mentions: 2012-06-03 09:59:18 UTC to 2025-08-01 16:14:33 UTC.

0123452012-01-01 00:00:00 UTC to 2013-01-01 00:00:00 UTC (exclusive): 5 mentions; 1 submissions, 4 comments20122013-01-01 00:00:00 UTC to 2014-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2014-01-01 00:00:00 UTC to 2015-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments2015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments2017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments20182019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2025

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20122012-01-01 00:00:00 UTC2013-01-01 00:00:00 UTC514
20132013-01-01 00:00:00 UTC2014-01-01 00:00:00 UTC101
20142014-01-01 00:00:00 UTC2015-01-01 00:00:00 UTC404
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC202
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC211
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC404
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC000
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC000
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC101
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC101
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC000
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC000
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC000
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC101

What Hacker News says

21 sources
asa400·Aug 1, 2025
This has nothing to do with math or number crunching on the BEAM. This has nothing to do with mutation. This has nothing to do with performance. This kind of process and function-local static single-assignment code is all over the place in Erlang codebases. It's incredibly common. The other popular method is tail recursion. I searched for literally 30 seconds and found these: - https://github.com/ninenines/cowboy/blob/master/src/cowboy_router.erl#L139-L144 - https://github.com/ninenines/cowboy/blob/master/src/cowboy.erl#L201-L205 - https://github.com/ninenines/cowboy/blob/master/src/cowboy_http2.erl#L487-L506
In Nova: A New Web Framework for Erlang
Cowicide·Oct 5, 2017
For those wondering what this is, I grabbed this from the zip file: = Cowboy Cowboy is a small, fast and modern HTTP server for Erlang/OTP. == Goals Cowboy aims to provide a complete HTTP stack in a small code base. It is optimized for low latency and low memory usage, in part because it uses binary strings. Cowboy provides routing capabilities, selectively dispatching requests to handlers written in Erlang. Because it uses Ranch for managing connections, Cowboy can easily be embedded in any other application. Cowboy is clean and well tested Erlang code. == Online documentation * https://ninenines.eu/docs/en/cowboy/2.0/guide[User guide] * https://ninenines.eu/docs/en/cowboy/2.0/manual[Function reference] == Offline documentation * While still online, run `make docs` * User guide available in `doc/` in PDF and HTML formats * Function refer
Read the rest
ence man pages available in `doc/man3/` and `doc/man7/` * Run `make install-docs` to install man pages on your system * Full documentation in Asciidoc available in `doc/src/` * Examples available in `examples/` == Getting help * Official IRC Channel: #ninenines on irc.freenode.net * https://github.com/ninenines/cowboy/issues[Issues tracker] * https://ninenines.eu/services[Commercial Support]
In Cowboy 2.0 released
randomstudent·Aug 17, 2017
Erlang has its own HTTP(s) servers, like cowboy (https://github.com/ninenines/cowboy) so it doesn't need Nginx and the like. Those servers simply take the place of Nginx. There is nothing special about Nginx that you can't copy in other languages, like Erlang. The main web framework for elixir, Phoenix, is just something that bundles cowboy (the webserver) with some utilities on top of it. No need for Nginx. I do use Nginx in my side projects in front of my Elixir web app, but that's because of some conveniences Nginx brings (having Nginx is probably making my requests a little slower).
In Elixir in Depth – Reading and personal notes
simoncion·Oct 4, 2015
My first attempt at making a simple Cowboy application was less than successful. I found the documentation spotty, inconsistent, and very difficult to understand. After about 45 minutes of really frustrated dicking around, I figured out how to make a simple HTTP server that allowed me to handle simple HTTP requests. I had to write code to switch on the passed-in HTTP verb, but everything worked, more or less. I could serve HTTP requests, but my code crashed after every request. (This was -of course- not fatal, but a bit of a performance killer.) Pipelined requests didn't work due to server connection resets. (Again, not fatal, just perf-diminishing.) I was utterly unable to get cowboy_rest to work. Several months later, with a lot of additional Erlang experience under my belt, I come back to the documentation, and it's -somehow- 60->70% c
Read the rest
omprehensible. I figured out what was wrong with my simple HTTP server. (I was calling my request handler in init, rather than returning {ok, Req, []}, and letting Cowboy call my request handler later.) I still can't get cowboy_rest to work, but (OTOH) I haven't spent more than five minutes trying to get it to work since my first attempt way back when. I don't know how much experience you have with Erlang, so I'll give you some basic advice that might be entirely unhelpful. Feel free to ask additional questions. Also feel free to ask questions on the erlang-questions mailing list. [0] Everyone who regularly posts there is very helpful. Many (most?) of them use Erlang professionally. Anyway. Advice: Projects/frameworks like OTP and Cowboy provide a callback API that application code is expected to conform to. Cowboy's documentation for this API is kind of all over the place, [1] but OTP's is well organized. [2] Because Erlang tries to eschew global state as much as it can, OTP has a convention that one of the values in the tuple returned from an callback is the state for that particular instance of your application code. This State variable seems to always be the last element in the returned tuple, and the last argument to your callback function. State can be any Erlang term; it only has meaning to your application code. If your callbacks don't care about state, then you can pass anything as state. Many other frameworks have adopted this convention; it's a pretty good one. Cowboy appears to be a pretty good HTTP/SPDY server. The beginner's documentation needs a LOT of love. (Even now, I had difficulty trying to piece together that walk through the docs in the footnote.) Given that it's a one-man shop, it's surprising that the docs are in as good a shape as they are; documentation isn't easy. :) But, still... Anyway, questions? Comments? Ask away either here, or on the erlang-questions mailing list. :) [0] http://erlang.org/mailman/listinfo/erlang-questions [1] First you have to read the examples shipped with the source code https://github.com/ninenines/cowboy/blob/1.0.x/examples/hell... https://github.com/ninenines/cowboy/blob/1.0.x/examples/hell... to kind of get the impression that you need to use the cowboy_http_handler API (kinda introduced here http://ninenines.eu/docs/en/cowboy/1.0/guide/http_handlers/ and documented here http://ninenines.eu/docs/en/cowboy/1.0/manual/cowboy_http_ha... ) in order to handle plain HTTP requests. If there's a better way to arrive at this conclusion, I overlooked it. :( [2] For example, the docs for OTP's application API: http://www.erlang.org/doc/man/application.html or the gen_server API: http://www.erlang.org/doc/man/gen_server.html The parts before the "CALLBACK FUNCTIONS" section are functions you use to manipulate an application or gen_server. The bits after are functions you implement in your module that the application or gen_server machinery will call.
In Erlang/OTP architectures: Cowboy
rdtsc·Feb 27, 2015
> Should I just ignore my trepidations and proceed? Yap give it a try. From what I understand Core.typed while not as rigorous as static type system in Haskell or OCaml can let you gradually add typing to your application. They more you add the greater the benefit. But also personally haven't used it. I used Dialyzer in Erlang, which is a similar concept. You annotate your code with types and the more you do the more type errors it will find for you: http://learnyousomeerlang.com/dialyzer It is surprisingly good. Here is example of production code in Erlang with some type annotations (it is a websocket handler from Cowboy a webserver): https://github.com/ninenines/cowboy/blob/master/src/cowboy_w... Notice the type and -callback declarations at the top then the -spec lines before some functions.
In Clojure at a Bank – Moving from Java (2012)

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