Mechaml is a functional web scraping library that allows to :

  • Fetch web content
  • Analyze, fill and submit HTML forms
  • Handle cookies, headers and redirections

Mechaml is built on top of existing libraries that provide low-level features : Cohttp and Lwt for asynchronous I/O and HTTP handling, and Lambdasoup to parse HTML. It provides an interface that handles the interactions between these and add a few other features.


The library is divided into 3 main modules :

  • Agent : User-agent features. Perform requests, get back content, headers, status code, ...
  • Cookiejar : Cookies handling
  • Page : HTML parsing and forms handling

The Format module provides helpers to manage the formatted content in forms such as date, colors, etc. For more details, see the documentation


From opam

opam install mechaml

From source

Mechaml uses the dune build system, which can be installed through opam. Then, just run

dune build

to build the library.

Use dune build @doc to generate the documentation, dune runtest to build and execute tests, and dune build examples/XXX.exe to compile example XXX.


Here is sample of code that fetches a web page, fills a login form and submits it in the monadic style:

open Mechaml
module M = Agent.Monad
open M.Infix

let require msg = function
  | Some a -> a
  | None -> failwith msg

let action_login =
  Agent.get ""
  >|= (function page ->
    |> Page.form_with "[name=login]"
    |> require "Can't find the login form !"
    |> Page.Form.set "username" "mynick"
    |> Page.Form.set "password" "@xlz43")
  >>= Agent.submit

let _ = (Agent.init ()) action_login

More examples are available in the dedicated folder.

AuthorYann Hamdaoui <>
Issue Tracker
MaintainerYann Hamdaoui <>
Source [http]
No package is dependent