The first that comes to mind is GNUCash, but I also asked chatgpt and here is what I got:
There are several open-source accounting software options that work offline and support invoicing. Here are some popular ones:
1. **GnuCash**
- Platforms: Windows, macOS, Linux
- Features: GnuCash provides double-entry bookkeeping, stock/bond/mutual fund accounts, small-business accounting, reports, graphs, QIF/OFX/HBCI import, transaction matching, scheduled transactions, and more. It also allows you to manage invoicing and vendor management.
- Website: [https://www.gnucash.org/](https://www.gnucash.org/)
2. **Manager**
- Platforms: Windows, macOS, Linux
- Features: Manager provides a wide range of accounting tools including invoicing, cash management, and financial reporting. While it has a cloud version, you can also download a desktop version that works offline.
- Website: [https://www.manager.io/](https://www.manager.io/)
3. **FrontAccounting**
- Platforms: Web-based (so you'd need a local server setup to run it offline)
- Features: FrontAccounting is more than just accounting software; it's an ERP system. It can handle purchases, payments, inventory management, and sales. Invoicing is one of its core features.
- Website: [https://frontaccounting.com/](https://frontaccounting.com/)
4. **KMyMoney**
- Platforms: Windows, macOS, Linux
- Features: Developed by KDE, KMyMoney is designed primarily for personal finance but can be adapted for small business use. It supports invoicing, investments, and various types of accounts.
- Website: [https://kmymoney.org/](https://kmymoney.org/)
5. **TurboCASH**
- Platforms: Windows
- Features: TurboCASH is geared towards small to medium-sized businesses. It offers features like debtors, creditors, invoicing, stock, and more.
- Website: [http://www.turbocash.net/](http://www.turbocash.net/)
While evaluating which software to choose, always consider:
- The complexity of your business operations and the features you need.
- How user-friendly the software is.
- Whether the software is actively maintained and updated.
- The community and documentation/support available.
It's always a good idea to test a few options before settling on one to see which one best fits your needs.