About Compere

What it is

Compere is an open-source project from Skelf-Research. It ships as a Python 3.11+ package on PyPI (pip install compere) and as a FastAPI server with an interactive /docs endpoint. The same code can be embedded as a library or run as a service backed by SQLite (default) or PostgreSQL.

What is actually inside

The repository contains exactly these algorithm modules:

• mab.py — Upper Confidence Bound (UCB1) for picking the next pair to compare. Configurable via UCB_EXPLORATION_CONSTANT (default 1.414) and UCB_UNEXPLORED_WEIGHT (default 1000.0).
• rating.py — Elo updates with configurable K-factor (ELO_K_FACTOR=32) and initial rating (ELO_INITIAL_RATING=1500).
• similarity.py — An alternative pairing strategy that selects similar entities for comparison instead of UCB-optimal ones.

That is the whole inference stack. There is no Bradley-Terry estimator, no Thurstone Case V, no TrueSkill / Glicko, no neural ranker. If you need those, compere is the wrong tool and we are happy to point you elsewhere.

HTTP surface

Eleven endpoints, all visible at http://localhost:8090/docs when running:

• Entities: POST /entities/, GET /entities/, GET/PUT/DELETE /entities/{id}
• Comparisons: POST /comparisons/, GET /comparisons/
• Pair selection: GET /mab/next_comparison, GET /comparisons/next
• Ratings: GET /ratings
• Health: GET /health, GET /health/ready

Deployment

A Dockerfile and docker-compose.yml ship in the repo. Optional knobs include JWT authentication (AUTH_ENABLED), CORS origins, and request rate limiting; all are off by default.

License and source

MIT. The source of truth is github.com/skelf-research/compere. Authoritative documentation lives at docs.skelfresearch.com/compere/.

Who built it

Skelf-Research is a small research group that publishes practical, narrowly-scoped tooling. Compere is one of those tools. If you have questions or want to contribute, issues and pull requests on the GitHub repository are the canonical channel.