DayZero API

Build accounting into your product

One REST API for transactions, invoices, bills, journal entries, reconciliations, and financial reports. Predictable resources, cursor pagination, and consistent errors — designed to feel obvious on the first request.

Start here

Authentication

Issue an API token, send the Authorization header, and scope every request to a business with x-business-id.

Your first request

Go from token to a live response in under five minutes with a copy-paste cURL example.

Explore the docs

API Reference

Every endpoint, parameter, schema, and response — with language code samples and machine-readable OpenAPI.

Guides

Task-focused walkthroughs for transactions, invoices, bills, reconciliation, reporting, and integrations.

Pagination

Page through large result sets with stable, cursor-based pagination instead of offsets.

Error handling

Understand status codes and the consistent JSON error shape so failures are easy to recover from.

Webhooks

Subscribe to events and react to changes in transactions, invoices, and reconciliations in real time.

AI & MCP

Plug DayZero into AI agents over the Model Context Protocol, plus llms.txt for ingestion.