mlgpx is the first Tangled-hosted package available on opam / Aug 2025

Since I wrote about the new ATProto-powered Tangled Git forge a few months ago, it's come along by leaps and bounds!

First, and most excitingly, they've added continuous integration via Spindles which are built in a nice ATProto style:

When you push code or open a pull request, the knot hosting your repository emits a pipeline event (sh.tangled.pipeline). Running as a dedicated service, spindle subscribes to these events via websocket connections to your knot.

The pipelines are Nix-only right now, so I braved using it^[1] for a new GPS Exchange Format library in OCaml that I wrote. The pipelines should look familiar, and the description format very straightforward.

Secondly, the service has added support for JJ stacked pull requests, which are the closest I've seen to the Jane Street Iron diff workflow which I've been wanting to try in open source for ages. You can see the interdiff review process on a recent PR by Winter who add support for engine-agnostic Spindle workflows, which should pave the path for a Docker or BuildKit engine alongside the existing Nixery-based one.

And thirdly, the general quality-of-life of the web frontend has improved dramatically, with a nice timeline, repo list, and profile pages. I'm running two knots right now (one on Recoil, and one in the Cambridge Computer Lab), and both have been very painfree. I wrote one of the earliest Dockerfiles for it, but there's now a community-maintained Knot Docker setup which I've switched to. Doesn't take very long at all; give it a try!

Because I've been using Tangled so much, I added support for Tangled metadata to Dune to make OCaml package maintainence easier. This will appear in Dune 3.21 in a few months, but in the meanwhile enjoy the first Tangled.sh package on opam. It's a simple GPX library I used in my recent trip to Botswana. All you need in your dune-project will be:

(lang dune 3.21)
(name mlgpx)
(generate_opam_files true)
(source (tangled @anil.recoil.org/ocaml-gpx))

The only major thing I'm missing from Tangled is support for private repositories now, but I'm very content using it for public content today. Beware as usual that it's still in alpha, so don't trust super-ultra-mega-important stuff to it unless you've git mirrored elsewhere.