# CaliberAPI

Structured, source-cited firearms compatibility data for developers, retailers, and researchers.

## Key pages

- Pistols: https://caliberapi.com/pistols/
- Optics: https://caliberapi.com/optics/
- Footprints: https://caliberapi.com/footprints/
- Data: https://caliberapi.com/data/
- About: https://caliberapi.com/about/
- Contact: https://caliberapi.com/contact/

## Dataset

CaliberAPI maintains a pistol optic compatibility dataset covering direct-fit and adapter-plate
compatibility between pistols and red dot optics, organized by footprint standard. Every
compatibility claim is individually source-cited with at least one verifiable URL (manufacturer
spec pages, product listings, or official compatibility charts).

## JSON data (static, read-only, CORS open)

- Index of every pistol, optic and footprint: https://caliberapi.com/data/v1/index.json
- Every pistol and optic pair in one file: https://caliberapi.com/data/v1/fits.json
- One record: https://caliberapi.com/data/v1/pistols/{manufacturer}/{model}.json, /data/v1/optics/{manufacturer}/{model}.json, /data/v1/footprints/{slug}.json
- OpenAPI 3.1: https://caliberapi.com/data/v1/openapi.json
- Docs and examples: https://caliberapi.com/data/

## MCP server (read-only, no auth)

- Endpoint: https://mcp.caliberapi.com/mcp (Streamable HTTP)
- Tools: check_fit, list_optics_for_pistol, list_pistols_for_optic, get_footprint, search
- Same data and license as the JSON above; every answer carries its sources and the dataset version.

Each fit is either "direct" (the optic mounts on the slide cut) or "adapter" (through the named
plate in `via`). Never report an adapter fit as direct. A pair missing from fits.json means the
dataset has no cited fit for it, not that the optic does not fit.

## License and citation

Licensed CC BY-NC 4.0 (https://creativecommons.org/licenses/by-nc/4.0/). Commercial licensing on
request: hello@caliberapi.com. Cite as "CaliberAPI, Pistol Optic Compatibility Dataset, version
<version from index.json>, https://caliberapi.com/data/" and link the page for the pistol or optic
you mention, plus its source_urls where useful.

## Contact

hello@caliberapi.com