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Quantum core

:watch: Cron-like job scheduler for Elixir

From quantum-elixir·Updated June 24, 2026·View on GitHub·

> **This README follows main, which may not be the currently published version**. Here are the [docs for the latest published version of Quantum](https://hexdocs.pm/quantum/readme.html). The project is written primarily in Elixir, distributed under the Apache License 2.0 license, first published in 2015. It has gained significant community traction with 2,411 stars and 153 forks on GitHub. Key topics include: cron, crontab, crontab-format, elixir, quantum.

Latest release: v3.5.3
February 29, 2024View Changelog →

Quantum

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This README follows main, which may not be the currently published version. Here are the
docs for the latest published version of Quantum.

Cron-like job scheduler for Elixir.

Setup

To use Quantum in your project, edit the mix.exs file and add Quantum to

1. the list of dependencies:

elixir
defp deps do [ {:quantum, "~> 3.0"} ] end

2. and create a scheduler for your app:

elixir
defmodule Acme.Scheduler do use Quantum, otp_app: :your_app end

3. and your application's supervision tree:

elixir
defmodule Acme.Application do use Application def start(_type, _args) do children = [ # This is the new line Acme.Scheduler ] opts = [strategy: :one_for_one, name: Acme.Supervisor] Supervisor.start_link(children, opts) end end

Troubleshooting

To see more transparently what quantum is doing, configure the logger to display :debug messages.

elixir
config :logger, level: :debug

If you want do use the logger in debug-level without the messages from quantum:

elixir
config :acme, Acme.Scheduler, debug_logging: false

If you encounter any problems with quantum, please search if there is already an
open issue addressing the problem.

Otherwise feel free to open an issue. Please include debug logs.

Usage

Configure your cronjobs in your config/config.exs like this:

elixir
config :acme, Acme.Scheduler, jobs: [ # Every minute {"* * * * *", {Heartbeat, :send, []}}, # Every 15 minutes {"*/15 * * * *", fn -> System.cmd("rm", ["/tmp/tmp_"]) end}, # Runs on 18, 20, 22, 0, 2, 4, 6: {"0 18-6/2 * * *", fn -> :mnesia.backup('/var/backup/mnesia') end}, # Runs every midnight: {"@daily", {Backup, :backup, []}} ]

More details on the usage can be found in the Documentation

Contribution

This project uses the Collective Code Construction Contract (C4) for all code changes.

"Everyone, without distinction or discrimination, SHALL have an equal right to become a Contributor under the terms of this contract."

TL;DR

  1. Check for open issues or open a new issue to start a discussion around a problem.
  2. Issues SHALL be named as "Problem: description of the problem".
  3. Fork the quantum-elixir repository on GitHub to start making your changes
  4. If possible, write a test which shows that the problem was solved.
  5. Send a pull request.
  6. Pull requests SHALL be named as "Solution: description of your solution"
  7. Your pull request is merged and you are added to the list of contributors

Copyright (c) 2015 Constantin Rack

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Contributors

Showing top 12 contributors by commit count.

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This article is auto-generated from quantum-elixir/quantum-core via the GitHub API.Last fetched: 6/27/2026