# PayCaptain Developers

> One API for UK payroll data. Send employees, shifts and pay elements in; read employees and payslips out. Every rule is published here, for people and for agents.

Every rule on this site is mandatory for integrations. Validate records in your own code before calling the API.

## Docs

- [Build on PayCaptain](https://developer.paycaptain.com/index.md): One API for UK payroll data. Send employees, shifts and pay elements in; read employees and payslips out. Every rule is published here, for people and for agents.
- [Quickstart](https://developer.paycaptain.com/quickstart.md): From API key to first accepted record in five steps.
- [Trust and security](https://developer.paycaptain.com/trust.md): What PayCaptain does to protect payroll data, and what your integration must do.
- [Employee fields](https://developer.paycaptain.com/fields/employee.md): Every field accepted by POST /employee and returned by GET /employees, with its validation rule.
- [Shift fields](https://developer.paycaptain.com/fields/shift.md): Every field accepted by POST /shift, with its validation rule.
- [Payment fields](https://developer.paycaptain.com/fields/payment.md): Every field accepted by POST /payment, with its validation rule.
- [Payslip fields](https://developer.paycaptain.com/fields/payslip.md): Every field returned by GET /payslips.
- [Business rules](https://developer.paycaptain.com/rules.md): The rules that span more than one field or more than one record. Enforce them alongside the field rules.
- [API reference](https://developer.paycaptain.com/api.md): Five endpoints, one header, JSON in and out.
- [Limits and retries](https://developer.paycaptain.com/reliability.md): Rate limits, retry behaviour and pagination.
- [Build with AI](https://developer.paycaptain.com/agents.md): Everything on this site in a form an agent or AI builder tool can read, plus a prompt sequence that produces a compliant integration.
- [Compliance tests](https://developer.paycaptain.com/testing.md): The 60 tests your integration must pass before it is deployed.

## Machine-readable

- [OpenAPI 3.0](https://developer.paycaptain.com/openapi.json): All endpoints and schemas
- [Employee JSON Schema](https://developer.paycaptain.com/schemas/employee.schema.json): Validate a employee record before POST /employee
- [Shift JSON Schema](https://developer.paycaptain.com/schemas/shift.schema.json): Validate a shift record before POST /shift
- [Payment JSON Schema](https://developer.paycaptain.com/schemas/payment.schema.json): Validate a payment record before POST /payment
- [Field data](https://developer.paycaptain.com/fields.json): Every field with its rules, as data
- [Compliance tests](https://developer.paycaptain.com/tests.json): The 60 tests an integration must pass
- [Whole site in one file](https://developer.paycaptain.com/llms-full.txt): Every page as Markdown