openxiv

OpenXiv is an AT Protocol preprint server with source-based submissions, public provenance, typed endorsements, OAI-PMH, and Bluesky federation. Maintained by davidichalfyorov-wq on GitHub, where it has earned 47 stars from the community.

It's actively developed around astro, atproto, bluesky, and is a solid reference for anyone building with these tools.