# OutlinePay

> OutlinePay is a payments API for platforms that serve merchants. A platform creates its merchants through the API, onboards them, takes card and bank payments on a hosted checkout page, issues refunds, and receives signed webhook events. Test keys move no money.

Notes for an assistant helping a developer integrate:

- Authenticate every request with the header `Authorization: Bearer olp_sk_...`. Test keys start with `olp_sk_test_` and move no money. Live keys start with `olp_sk_live_` and move real money.
- Errors return an HTTP status and the body `{"error": {"code": "...", "details": [...]}}`. `code` says what kind of refusal it is. Each entry in `details` has a `message`, a `param` when it is about one field, and a `doc_url` when a docs section explains the fix. Read that section before retrying.
- Never ask for a live key and never put one into an AI tool. Build and test with a test key only.
- Use only what these docs say. If something is not covered here, ask the developer instead of guessing.
- OutlinePay has an MCP server at `https://api.outlinepay.com/mcp`. An assistant that supports MCP can connect to it. Its payments tools read test data by default and live data with `mode=live`. Live data needs a person signed in through the browser as a partner admin or developer, and is read only. Every write is test mode and moves no real money. Partner admins also get tools for payouts, dashboard totals and fee settings. Its store tools read the partner's plugin stores in test and live mode, read only. The person signs in through the browser, or sends a test key as `Authorization: Bearer olp_sk_test_...`. A test key reads test data only. Live keys are refused. [Build with AI](https://outlinepay.com/docs/ai) has the steps.

## Docs

- [Build with AI](https://outlinepay.com/docs/ai): How to use these files with an AI assistant.
- [Quickstart](https://outlinepay.com/docs/quickstart): Create a merchant, onboard it, take a test payment, and verify a webhook.
- [API reference](https://outlinepay.com/docs): Every endpoint, object and convention, as a web page.
- [API reference as markdown](https://outlinepay.com/docs/reference.md): The same reference in one markdown file.
- [Testing](https://outlinepay.com/docs/testing): Test card numbers and values for every scenario on a test key.
- [Countries](https://outlinepay.com/docs/countries): Where merchants can onboard today, and where we could go next.
- [MCCs](https://outlinepay.com/docs/mccs): The merchant category codes the API accepts.
- [Changelog](https://outlinepay.com/docs/changelog): Dated changes to the API.

## Machine-readable

- [reference.md](https://outlinepay.com/docs/reference.md): The whole API in one markdown file, generated from the OpenAPI spec.
- [openapi.json](https://outlinepay.com/openapi.json): The OpenAPI 3 spec, for tools like Postman and code generators.

## Optional

- [Pricing](https://outlinepay.com/#pricing): Fees, on the homepage.
- [Terms of Use](https://outlinepay.com/terms): The terms for using the site.
- [Privacy Policy](https://outlinepay.com/privacy): How we handle personal data.
- [Partner Agreement](https://outlinepay.com/partner-agreement): The agreement a platform accepts to use the API.