# [RFC] yamlet: a YAML 1.2 library

> Source: <https://discourse.haskell.org/t/rfc-yamlet-a-yaml-1-2-library/14795#post_1>
> Published: 2026-10-04 07:16:36+00:00

I’ve been stress-testing Claude Opus 5.5 and thought a YAML library with a good API would fill a hole in the ecosystem. The result:

In short, yamlet is a YAML 1.2 library with fast encoding/decoding, preservation of structure (including comments where you want them) and support for generic deriving that compiles to good code for common shapes of data types.

If anyone was doing YAML processing in Haskell and found it lacking, have a look at the API. It was good enough for me to make [haskell-gha](https://github.com/arybczak/haskell-gha) without any workarounds, but if I missed something, I’d like to know before the first release.

Documentation is mostly Claude-generated, so expect an odd wording here and there, but there’s also plenty of doctests.