---
title: "Glossary and further reading · Builder's guide · Chappell AI"
description: "Appendix C of the GAAPcore builder's guide."
url: https://chappellai.us/guide/c-glossary-and-further-reading/
---

Builder's guide · Appendix C

# Glossary and further reading

| Term | Meaning |
| --- | --- |
| Console | Your application: the screens, people, workflow and controls |
| Writer (source system) | A registered application allowed to call GAAPcore, with a code, a role, a company scope and API keys |
| Control account | A GL account whose balance is the total of a subledger (receivables, payables, inventory, bank cash) |
| Subledger | The detail behind a control account: open invoices, open bills, FIFO layers, assets, leases |
| Tie-out | The check that a control account equals its subledger, or a bank equals its statement |
| FIFO layer | A quantity of stock at the cost it was received at; issues consume the oldest first |
| Conversion period | The earliest period, ending on the cut-over date, where the opening balance is posted |
| Idempotency key | A unique key per write, so a retry returns the first result instead of posting twice |
| Reversal | A new posting that undoes a posted document, linked to it; posted documents are never edited |
| Company group | Related companies that trade with each other and report consolidated statements |

## Where to read more

| File | What it holds |
| --- | --- |
| `Acctgheadless/docs/overview.md` | What GAAPcore is and what it covers |
| `Acctgheadless/api/README.md` | Installing and running the API |
| `Acctgheadless/api/openapi.yaml` | Every route and field |
| `Acctgheadless/docs/api-conventions.md` | Headers, money, errors, idempotency, restricted accounts |
| `Acctgheadless/docs/authentication-design.md` | Writers, roles, scope, keys |
| `Acctgheadless/catalog/` | One specification per transaction type |
| `gaapcore-console/docs/patterns.md` | The 33 integration patterns behind this guide, each pointing at the code that shows it |
| `gaapcore-console/docs/build-notes/` | What each chunk built, and what to try |