# InvoiceCow

> InvoiceCow turns each paid sale of a merchant into an invoice in the merchant's company name. Each buyer gets a page to add their company details and download their invoices. Stripe connects directly; any other checkout sends signed webhooks or CSV files. InvoiceCow never calculates tax: each invoice shows the tax the checkout charged.

An agent on the merchant's computer can connect a service to InvoiceCow. The person does three things, at most: create or confirm the account and accept the Terms, approve the agent's token, and authorize the processor. The agent does the rest through the API or the MCP server.

Stripe connects with a restricted key that the person enters in the dashboard, or in one click through the InvoiceCow Stripe App (Pending Stripe review). Each invoice and credit note is a PDF. InvoiceCow also makes each e-invoice file that the document's data allows, and offers a file only after it passes validation. The formats: XRechnung, UBL, CII, Peppol BIS, and Factur-X and ZUGFeRD (Planned).

## Docs

- [Agents guide](https://invoicecow.com/developers/agents.md): The recipe to connect a service, step by step: the token, the company, the numbering, the processor, the receipt text, the test sale and the check. What to ask the person, and what never to do.
- [Developers](https://invoicecow.com/developers.md): The API, the tokens and their scopes, the MCP server and its tools, Stripe, the signed webhook, the buyer page and the rule labels.
- [OpenAPI 3.1](https://invoicecow.com/api/v1/openapi.json): Every endpoint of the API v1, with its scope, its answers and its errors.

## API

- [API v1](https://invoicecow.com/developers.md#the-api): JSON at `https://invoicecow.com/api/v1`. Every request sends `Authorization: Bearer <token>`. Every write sends an `Idempotency-Key`.
- [Agent authorization](https://invoicecow.com/developers/agents.md#1-get-a-token): The OAuth 2.0 device flow (RFC 8628): the agent asks, the person approves once, the agent receives its token.
- [MCP server](https://invoicecow.com/developers.md#the-mcp-server): `https://invoicecow.com/mcp`, Streamable HTTP, with the API token as the bearer; how to add it to Claude Code, Cursor and Codex.

## Optional

- [Full text](https://invoicecow.com/llms-full.txt): This file, the developers page and the agents guide in one file.
- [Signed webhook](https://invoicecow.com/developers/agents.md#the-signed-webhook): The event shape, the signature, and a sale call in 20 lines of Ruby or TypeScript.