Fmt exposes combinators to devise Format pretty-printing functions.

Core is an alternative to the OCaml standard library.

Core_kernel is the system-independent part of Core. It is aimed for cases when the full Core is not available, such as in Javascript.

Alcotest exposes simple interface to perform unit tests. It exposes a simple TESTABLE module type, a check function to assert test predicates and a run function to perform a list of unit -> unit test callbacks. Alcotest provides a quiet and colorful output where only faulty runs are fully displayed at the end of the run (with the full logs ready to inspect), with a simple (yet expressive) query language to select the tests to run.

This package can automatically generate runtime types from type definitions.

OCamlbuild is a generic build tool, that has built-in rules for building OCaml library and programs.

Yojson is an optimized parsing and printing library for the JSON format. It addresses a few shortcomings of json-wheel including 2x speedup, polymorphic variants and optional syntax for tuples and variants. ydump is a pretty printing command-line program provided with the yojson package. The program atdgen can be used to derive OCaml-JSON serializers and deserializers from type definitions.

Libraries for creating shared memory producer/consumer rings. The rings follow the Xen ABI and may be used to create or implement Xen virtual devices.

Merlin is an editor service that provides modern IDE features for OCaml. Emacs and Vim support is provided out-of-the-box. External contributors added support for Visual Studio Code, Sublime Text and Atom.

This package provides types and operations over dates and times.

OCaml-Num contains the legacy Num library for arbitrary-precision integer and rational arithmetic that used to be part of the OCaml core distribution.

This package provides a library for parsing the contents of OCaml documentation comments, formatted using Odoc syntax, an extension of the language understood by ocamldoc.

This package includes only the ocp-index library and command-line tool.

This library provides facilities to parse version numbers of the OCaml compiler, and enumerates the various official OCaml releases and configuration variants.

Crowbar is a library for testing code, combining QuickCheck-style property-based testing and the magical bug-finding powers of afl-fuzz.

Tuareg helps editing OCaml code, to highlight important parts of the code, to run an OCaml REPL, and to run the OCaml debugger within Emacs.

This package contains assert-like extension nodes that raise useful errors on failure.

This library provides minimal support for Canonical S-expressions. Canonical S-expressions are a binary encoding of S-expressions that is super simple and well suited for communication between programs.

This library only provides a few helpers for simple applications. If you need more advanced support, such as parsing from more fancy input sources, you should consider copying the code of this library given how simple parsing S-expressions in canonical form is.

To avoid a dependency on a particular S-expression library, the only module of this library is parameterised by the type of S-expressions.

This project provides a Mmap.map_file function for mapping files in memory. This function is the same as the Unix.map_file function added in OCaml >= 4.06.

base-quickcheck provides randomized testing in the style of Haskell's Quickcheck library, with support for built-in types as well as types provided by Base.

Crowbar is a library for testing code, combining QuickCheck-style property-based testing and the magical bug-finding powers of afl-fuzz.

Luv is a binding to libuv, the cross-platform C library that does asynchronous I/O in Node.js and runs its main loop. Besides asynchronous I/O, libuv also supports multiprocessing and multithreading. Multiple event loops can be run in different threads. libuv also exposes a lot of other functionality, amounting to a full OS API, and an alternative to the standard module Unix.

This package provides ppx_sexp_message-like extension nodes for lazily rendering log messages.

BEnchmark for a CHAMEL/camel/caml which is agnostic to the system. It's a micro-benchmark tool for OCaml which lets the user to re-analyzes and prints samples.

This package backports new language features such as let+ to older OCaml compilers.