Documentation

Costslice docs

Costslice is a pass-through OpenAI proxy plus a tenant P&L. It is not an AI gateway: no routing, fallbacks, semantic cache, or virtual keys. We store usage metadata only — never prompts or completions.

10-minute quickstart — Python, Node, and Vercel AI SDK
Proxy host: https://api.costslice.com/v1
App: https://costslice.com
Usage API: GET https://costslice.com/api/v1/spend with x-cs-key

What we store

Per request: org, request id, timestamp, provider, model, tenant, feature, env, token counts, cost, latency, status, and whether cost came from the provider, an estimate, or an unpriced model. No body. No payload logging in MVP, and we do not train on customer data because we do not keep it.

Headers

Authorization	Your OpenAI key. Forwarded. Never logged.
x-cs-key	Costslice workspace key. Identifies your org.
x-cs-tenant	Opaque tenant id, max 128 chars. Not an email.
x-cs-feature	Feature name, max 128 chars.
x-cs-env	prod \| staging \| dev. Defaults to prod.

Missing tenant: we accept OpenAI user, then fall back to untagged. We fail-open on tags so a forgotten header never eats the completion.