Web client with HTTP/1, HTTP/2, TLS, and WebSocket support









Straightforward, full-featured Web client that composes with Dream.

Lwt_main.run begin
  let%lwt response = Hyper.get "http://google.com" in
  print_string response;

Note: the client is not actually full-featured yet :) This README is also an
extremely rough sketch :) This repository is a work in progress

Hyper is the client counterpart to Dream, the Web server framework.
Hyper uses the same types and the same programming model. Like Dream, Hyper
offers one module, which features a bunch of easy-to-use functions. Also like
Dream, Hyper still exposes the underlying highly composable functions, for full


At the moment, Hyper offers only three main "stable" values:

Hyper.get : string -> string promise
Hyper.post : string -> string -> string promise
Hyper.websocket : string -> websocket promise

These support all the same Web protocols as Dream: HTTP/1, HTTP/2, TLS, and
WebSocket, and they follow redirects. The protocols are selected using URI

Hyper.get "http://google.com"
Hyper.post "https://some.app/endpoint" "{}"
Hyper.websocket "ws://some.site/socket"

You can see early usage in the examples.

These are actually wrappers around a "stack" of request -> response promise
handlers and client-side middlewares, but the elements of that stack are not
mature enough to expose yet. They will eventually be exposed to quickly build
custom clients with any desired behavior.

For testing WebSockets, Hyper offers an interface similar to
the one in Dream:

Hyper.send : websocket -> string -> unit promise
Hyper.receive : websocket -> string option promise
Hyper.close_websocket : websocket -> unit promise


A Hyper client and a Dream server have exactly the same type,
request -> response promise.

This means that the client's lowest layer can be implemented by swapping out
connecting over the network by a direct call to an in-process Dream server,
which can be useful for no-network testing.

Conversely, a Dream server can pass the requests it receives to a Hyper client,
thus acting as a proxy. Responses received from the proxy client can be directly
returned by the server to its client.

In all cases, all body streams and WebSockets get forwarded automatically as a
side effect of the conventions followed by Hyper and Dream.


  • [ ] Restore connection pooling and multiplexing.

  • [ ] 🛑 Server certificate validation.

  • [ ] File uploads (multipart streams).

  • [ ] Cookie store.

  • [ ] Redirect cache.

  • [ ] Automatic decompression.

  • [ ] wss:// (WebSockets over TLS).

  • [ ] Many miscellania.


Open an issue, or visit...

Highlight @antron to poke @aantron specifically.


To work on Hyper, clone Dream and Hyper into a single Dune workspace:

mkdir my-directory
cd my-directory
touch dune-workspace
git clone --recursive https://github.com/aantron/dream.git
git clone https://github.com/aantron/hyper.git
cd hyper


As with Dream, Hyper makes extensive use of the http/af-like Web protocol stack
by Antonio Nuno Monteiro.