Several solid options are free and open source, and they split into desktop programs and self-hosted web apps.
- GnuCash: The long-running double-entry desktop program for Windows, macOS and Linux. It's stable and offline, but the interface is plain and automation is limited. A recent review cites GnuCash 5.16 as the current stable release.
- Akaunting: A self-hosted web app aimed at small businesses and freelancers, with multi-currency and multi-language support. Its free version has invoicing, expenses and reports, but some reviewers note it lacks full double-entry accounting, and advanced features often come as paid add-ons.
- ERPNext: A full business suite where accounting is the core, with inventory, orders and HR included. It's powerful, but it takes more effort to set up.
- Odoo Community: Free accounting and invoicing inside a larger business app. Some features are reserved for the paid Enterprise edition.
- Frappe Books: A modern desktop app for invoices, expenses and bookkeeping, aimed at small businesses.
- LedgerSMB: An open-source ERP accounting system for growing businesses, with a steep learning curve.
For a single owner who wants double-entry books on their own computer, GnuCash is the usual pick. For invoicing and several users on a server, Akaunting or ERPNext fit better. Check each project's license and whether your tax rules are supported before you commit, since the sources I found are reviews and rankings, not audits of each program.
🕒 As of October 2026