Kwill

API Reference

Complete reference for the Kwill REST API.

Full reference documentation for every Kwill API endpoint.

Base URL

https://usekwill.com/api/v1

Authentication

All API requests require a valid API key passed in the Authorization header:

Authorization: Bearer YOUR_API_KEY

Use the sidebar to browse endpoints by resource — Clients, Projects, Invoices, Proposals, and Webhooks. Every endpoint is documented with request parameters, response schemas, and example payloads generated directly from the Kwill OpenAPI spec.

Get notified when an invoice is paid or a proposal is signed

Register a webhook, verify signatures, and handle invoice.paid and proposal.signed events end-to-end.

List clients

Active (non-archived) clients, newest first, each with a summary of its proposals and invoices.

On this page

Base URLAuthentication