Faktory is an open-source background job server by Mike Perham, the creator of Sidekiq. Producers push jobs as JSON and workers fetch them over a small protocol, so any language can use it: official Ruby and Go clients, community ones for Python, Node, PHP, Rust, Elixir, Java, .NET and more. A fetched job is reserved, not removed: if a worker crashes, it comes back. Failures retry with backoff, then land in a Dead set you can re-run. Web UI included.