Announcing hex_core

August 8, 2018 · by Wojtek Mach

Today we are releasing the first version of hex_core, an Erlang library to interact with and other servers implementing Hex specifications.

Before talking about hex_core, let’s ask a simple question: What is Hex? The short answer is, it’s a package manager for the Erlang ecosystem. The long answer is that by Hex we may mean a few different things:

  1. A set of specifications of building clients and servers that can interact with each other:
  2. A server for hosting packages like the official server located at
  3. Clients for interacting with servers, e.g. Hex for Elixir and rebar3_hex for Erlang projects

The goal of hex_core is to be the reference implementation of Hex specifications used by Hex clients and servers.

As of this announcement the hex_core package itself is available on

Usage in an Erlang project

  1. Create a new project: rebar3 new lib example
  2. Add hex_core to rebar.config:
   {deps, [
     {hex_core, "0.1.0"}
  1. Start the shell to and count all packages published to
   $ rebar3 shell
   erl> inets:start(), ssl:start(),
   erl> Config = hex_core:default_config(),
   erl> {ok, {200, _, #{packages := Packages}}} = hex_repo:get_names(Config),
   erl> length(Packages).

Usage in an Elixir project

  1. Create a new project: mix new example
  2. Add hex_core to mix.exs:
   defp deps() do
     [{:hex_core, "~> 0.1"}]
  1. Start the shell to and search for all packages matching query “riak”:
   $ iex -S mix
   iex> :inets.start() ; :ssl.start()
   iex> config = :hex_core.default_config()
   iex> options = [sort: :downloads]
   iex> {:ok, {200, _, packages}} =, "riak", options)
   iex>, & &1["name"])
   ["riak_pb", "riakc", ...]

See README at for more usage examples.

Future work

After the initial release we plan to work with the community to integrate hex_core into their projects and respond to feedback.

We will also be focused on releasing a minimal Hex server, built on top of hex_core, to be a starting point for people wanting to run Hex on their own infrastructure. Stay tuned!