# ZeroClick

> ZeroClick turns any API or offering into an agent-purchasable service. Sellers connect an existing API; ZeroClick hosts a machine-readable storefront and payment gateway at a pay URL (for example `https://acme.pay.zeroclick.io`), agents pay per use or purchase plans over the x402 and MPP protocols, and ZeroClick forwards each paid request to the seller's API, signed. Revenue settles to the seller's Stripe account.

Two audiences read these docs. **Sellers** integrate ZeroClick into their backend: start at the quickstart. **Buying agents** do not need these docs to make a purchase: every seller storefront publishes its own instructions at `https://<seller>.pay.zeroclick.io/llms.txt`, with prices, plans, and payment steps for that seller. Fetch that file and follow it.

Every page below is also available as plain markdown: append `.md` to its URL, or send `Accept: text/markdown`.

## Start here

- [What is ZeroClick](https://docs.zeroclick.ai/index.md): the product in one page, with the request lifecycle
- [Quickstart](https://docs.zeroclick.ai/quickstart.md): add the billing guard to an existing API and serve a paid agent request
- [How ZeroClick works](https://docs.zeroclick.ai/concepts/how-zeroclick-works.md): the full protocol lifecycle with a sequence diagram

## Integrate your API

- [Integration overview](https://docs.zeroclick.ai/integrate/overview.md): the whole contract: verify, check allowance, serve, settle
- [Keys and secrets](https://docs.zeroclick.ai/integrate/keys-and-secrets.md): signing secrets, scoped usage keys, rotation
- [Verify requests](https://docs.zeroclick.ai/integrate/verify-requests.md): signature verification and the raw-path rule
- [Check allowances](https://docs.zeroclick.ai/integrate/check-allowances.md): guard before work; denial and outage handling
- [Settle usage](https://docs.zeroclick.ai/integrate/settle-usage.md): the zc-usage header and asynchronous reports
- [Charge up to a maximum](https://docs.zeroclick.ai/integrate/charge-up-to-a-maximum.md): ceilings for work you can't size up front
- [Free and identity endpoints](https://docs.zeroclick.ai/integrate/free-and-identity-endpoints.md): identity-scoped free calls and included units
- [REST walkthrough](https://docs.zeroclick.ai/integrate/rest-walkthrough.md): the same contract with plain HTTP, no SDK
- [Signature spec](https://docs.zeroclick.ai/integrate/signature-spec.md): the byte-level zc-signature specification with a test vector

## SDKs

- [SDK overview](https://docs.zeroclick.ai/sdks/overview.md): TypeScript, Python, and Go compared
- [TypeScript quickstart](https://docs.zeroclick.ai/sdks/typescript/quickstart.md): `@zeroclickai/sellers` on npm
- [Python quickstart](https://docs.zeroclick.ai/sdks/python/quickstart.md): `zeroclick-sellers` on PyPI
- [Go quickstart](https://docs.zeroclick.ai/sdks/go/quickstart.md): `cdn.zeroclick.io/sdks/sellers-go`

## API reference

- [API reference introduction](https://docs.zeroclick.ai/api-reference/introduction.md): base URL, auth, scopes, conventions
- [OpenAPI specification](https://api.zeroclick.io/openapi.json): the live machine-readable spec for the management REST API

## Reference

- [Errors](https://docs.zeroclick.ai/resources/errors.md): every error surface, from the REST envelope to pay URL codes
- [Headers](https://docs.zeroclick.ai/resources/headers.md): the zc-* and payment header catalog

## Optional

- [Concepts: sellers, services, and meters](https://docs.zeroclick.ai/concepts/stores-services-meters.md)
- [Concepts: plans and pricing](https://docs.zeroclick.ai/concepts/plans-and-pricing.md)
- [Concepts: agents and access](https://docs.zeroclick.ai/concepts/agents-and-access.md)
- [Concepts: usage and allowances](https://docs.zeroclick.ai/concepts/usage-and-allowances.md)
- [Concepts: payment protocols](https://docs.zeroclick.ai/concepts/payment-protocols.md)