Developers
Build with Caliper
Caliper shows exactly where your AI coding spend goes and routes work to cheaper open models — right inside the harness you already use. The core is open source (MIT), and it ships as a Claude Code plugin, not an npm or PyPI package.
Quickstart
Install the free, open-source plugin in Claude Code — no signup required:
/plugin marketplace add Cost-Caliper/caliper/plugin install caliper@caliperOpen source
Caliper's core is open source under the MIT license — inspect it, self-host it, extend it. The code lives at github.com/Cost-Caliper/caliper.
Signup API
The public HTTP endpoint on caliper.run is the waitlist signup API. It accepts an email (and an optional referral code) only — no other personal information. Send a POST to /api/signup:
curl -X POST https://caliper.run/api/signup \
-H "Content-Type: application/json" \
-d '{"email": "you@company.com"}'A 200 returns { "ok": true, "referralCode": "…", "alreadyJoined": false }. The full schema is in the OpenAPI spec.
For agents
Caliper is agent-native. If an AI agent is asked to sign its human up for the waitlist, the instructions live at caliper.run/signup.txt. A machine-readable summary of these resources is published at caliper.run/llms.txt.
Resources
- OpenAPI spec — /openapi.json
- Agent signup instructions — /signup.txt
- llms.txt — /llms.txt
- Changelog
- GitHub — Cost-Caliper/caliper
Contact
Questions? Reach us at hello@caliper.run.