---
title: "Who this guide is for · Builder's guide · Chappell AI"
description: "You run a business, or build software for one, and you want accounting screens that fit how that business works. You don't want to build an accounting engine to get them."
url: https://chappellai.us/guide/01-who-this-guide-is-for/
---

Builder's guide · Section 1

# Who this guide is for

You run a business, or build software for one, and you want accounting screens that fit how that business works. You don't want to build an accounting engine to get them.

GAAPcore is that engine. It is a **headless** accounting core: it has no screens of its own. It keeps the general ledger, the subledgers (customers, vendors, inventory, fixed assets, leases, bank) and the financial statements, and it enforces US GAAP accounting rules inside the database. Your **console** is the part people see and use: the screens, the workflow, the sign-in and the approvals.

The guide is written for two readers working together:

-   **The owner or operator**, who decides what the console must do, who uses it, and which controls the business needs. Read sections 1–4, 9–10 and 12–14.
-   **The builder**, a developer or a coding agent directed by one, who writes the console. Read everything. The technical rules are in sections 5–8 and the appendices.

A working example exists

Everything in this guide has already been built once. The reference console, `gaapcore-console`, runs the books of a demonstration coffee roaster (Lantern Hill Coffee Roasters) and its sister café, covering purchasing, roasting, sales, banking, assets, the close and intercompany trade. When this guide says “the reference console”, it means that repository. Its file `docs/patterns.md` is the detailed companion to this guide.

## What you will end up with

-   A web application your staff sign in to, with screens for the parts of the business that touch the books.
-   A small server that holds your console's GAAPcore key and passes requests to the GAAPcore API, recording which person asked for each one.
-   An GAAPcore installation (its API and its PostgreSQL database) that holds the books and refuses anything that would make them wrong.