Your books, minus the busywork.

Open-source accounting that runs inside Claude. Built for solo operators, freelancers, and small teams who would rather do the work than learn another dashboard.

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Real double-entry ledger
Self-hostable
No credit card

CosBooks

connected

Invoice Northstar Studio $2,400 for the August brand project, due in 14 days.

Invoice #1042 created for Northstar Studio.

Total

$2,400.00

Status

Posted

Ask about cash flow, invoices, expenses…

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Built for small, serious businesses

Solo operators

Stay close to cash without becoming your own full-time bookkeeper.

Freelancers

Send invoices, track expenses, and get tax-ready numbers in plain English.

Small teams

Share one reliable ledger with clear roles and a complete audit trail.

How it works

You talk. The ledger does the accounting.

Claude handles the conversation. CosBooks handles the rules that cannot be fuzzy.

01
Say what happened
“Invoice Northstar $2,400 for the August project.”
02
Claude structures it
CosBooks receives a typed, explicit accounting action.
03
The ledger verifies it
Ownership, permissions, and balanced entries are checked before commit.

The essentials

A real accounting system. Just less software.

Everything a lean business needs to keep accurate books, with fewer screens and no feature maze.

Invoices & bills

Create, send, collect, and know exactly what is due.

Bank reconciliation

Import activity, match transactions, and resolve differences.

Payments

Record incoming and outgoing money with clean allocations.

Financial reports

P&L, balance sheet, cash flow, aging, and trial balance.

Double-entry core

Every posting must balance before it reaches your books.

Roles & audit trail

Scoped access, isolated organizations, and reviewable changes.

Open source by default

Your financial system should not be a black box.

Inspect the posting rules, own the data model, self-host the server, or contribute a better workflow. CosBooks is built in public for people whose businesses deserve transparent tools.

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