Quick answer
The best open source billing software for most small businesses is Lago, with Kill Bill and FOSSBilling as strong alternatives. Verified 16 October 2026.
Billing means recurring charges: subscriptions, usage-based plans and automated invoices. This is different from sending a one-off invoice. Open source billing tools are aimed mostly at software and service businesses, and they usually need a developer to integrate them.
We write for small businesses, freelancers and growing teams, not large enterprises. Every tool below was checked on GitHub for license, archive status and recent activity, and prices are never quoted because they change. Our picks are based on each project's documentation and repository data, not on hands-on benchmarks, so always try a tool with sample data first. This is general information, not tax, legal or accounting advice.
Top picks at a glance
- Lago: Usage-based and subscription billing.
- Kill Bill: Subscription billing and payments.
- FOSSBilling: Hosting and service providers.
What to look for in billing software for a small business
- Recurring and usage support. Check that it handles the way you charge: fixed plans, per-seat, usage or hybrid.
- Payment gateway support. Make sure it works with a gateway available in your country.
- Tax handling. Billing for customers in other regions adds tax rules. Confirm what the tool automates.
- Developer effort. Billing engines like Lago and Kill Bill expect API integration. Do not choose them if nobody can code.
- Project health and license. Choose a project that is not archived, has recent releases and a real open source license. Check the LICENSE file, not just the website.
Comparison table: best open source billing software
| Tool | Best for | License | Stack | GitHub stars | Repo updated |
|---|---|---|---|---|---|
| Lago | Usage-based and subscription billing | AGPL-3.0 | Ruby/Go, PostgreSQL | 10,686 | Oct 2026 |
| Kill Bill | Subscription billing and payments | Apache-2.0 | Java | 5,797 | Oct 2026 |
| FOSSBilling | Hosting and service providers | Apache-2.0 | PHP | 1,716 | Oct 2026 |
| Meteroid | Pricing and billing infrastructure | AGPL-3.0 | Rust, PostgreSQL | 1,333 | Oct 2026 |
| Dolibarr ERP CRM | Simple recurring invoices | GPL-3.0 | PHP, MySQL/MariaDB/PostgreSQL | 7,732 | Oct 2026 |
| ERPNext | Subscriptions inside an ERP | GPL-3.0 | Python (Frappe), MariaDB | 40,232 | Oct 2026 |
Stars and update dates are a snapshot from 16 October 2026 and change daily. They show activity, not quality.
The 6 best open source billing tools, reviewed
1. Lago
Best for: Usage-based and subscription billing
License: AGPL-3.0 · Stack: Ruby/Go, PostgreSQL · GitHub: 10,686 stars, repo updated Oct 2026
Open source billing engine for metering usage, pricing plans and generating invoices. Built for software products and needs developer integration.
Source on GitHub · Official website
2. Kill Bill
Best for: Subscription billing and payments
License: Apache-2.0 · Stack: Java · GitHub: 5,797 stars, repo updated Oct 2026
A long-established Java platform for subscription billing and payments. Powerful and flexible, but heavier to run.
Source on GitHub · Official website
3. FOSSBilling
Best for: Hosting and service providers
License: Apache-2.0 · Stack: PHP · GitHub: 1,716 stars, repo updated Oct 2026
A PHP billing and client management system, commonly used by web hosting and service providers that sell recurring services.
Source on GitHub · Official website
4. Meteroid
Best for: Pricing and billing infrastructure
License: AGPL-3.0 · Stack: Rust, PostgreSQL · GitHub: 1,333 stars, repo updated Oct 2026
A newer Rust-based project for subscription and usage-based pricing and billing. Young, so test it thoroughly.
Source on GitHub · Official website
5. Dolibarr ERP CRM
Best for: Simple recurring invoices
License: GPL-3.0 · Stack: PHP, MySQL/MariaDB/PostgreSQL · GitHub: 7,732 stars, repo updated Oct 2026
Handles customer invoices and can repeat them on a schedule. A practical fit for small businesses with a few recurring clients.
Read our full guide to Dolibarr ERP CRM · Source on GitHub · Official website
6. ERPNext
Best for: Subscriptions inside an ERP
License: GPL-3.0 · Stack: Python (Frappe), MariaDB · GitHub: 40,232 stars, repo updated Oct 2026
Includes subscription and invoicing features within a full ERP, useful if billing must connect to accounting and stock.
Read our full guide to ERPNext · Source on GitHub · Official website
Open source vs paid billing software
Paid cloud products usually win on polish, mobile apps, automatic bank connections and support. Open source wins on running cost as you grow, data ownership and the freedom to customize. The real cost of open source is hosting, backups, updates and your own time, so count those honestly. Several of these projects also sell hosting or support if you would rather not run a server yourself.
How to choose the best billing software
- You sell a software product with usage pricing: Lago.
- You run a hosting or service business: FOSSBilling.
- You have a few recurring clients: Dolibarr or ERPNext.
- You need deep customization and have Java skills: Kill Bill.
Popular tools that are not open source (or not maintained)
These names show up in many "open source" lists, so check the license before you choose them:
- BillaBear: Licensed under the Fair Core License, which is not an open source license. Repository
Checked from the projects' LICENSE files and GitHub status on 16 October 2026. Licenses can change.
Mistakes to avoid
BillaBear, a billing tool that markets itself as open source, uses the Fair Core License, which is not an open source license. Billing handles money and tax, so test with small amounts and ask an accountant about invoice and tax rules before going live.
Where to host it
All of these tools can be self-hosted. A small VPS or a web hosting plan from a provider such as Hostinger is enough to get started with most of them. Check each project's requirements first, and read our security and backup checklist before you add real data.
Need a server to host it?
Self-hosting a CRM needs a server. PHP and MySQL apps can often run on ordinary web hosting, while Docker, Node, Python or Java apps usually need a VPS. Check each project's requirements first. Hostinger offers both shared web hosting and VPS plans.
Affiliate disclosure: this is an affiliate link. If you buy through it we may earn a commission at no extra cost to you. CRMs are listed independently of any hosting partner. Learn more.
Related comparisons
- Best Open Source Invoicing Software for Small Business
- Best Open Source Accounts Receivable Software (2026)
- Best Open Source Accounting Software for Small Business
- Best Open Source Revenue Recognition Software (2026)
All open source business software comparisons
- Accounting
- Bookkeeping
- Billing
- Invoicing
- Payroll
- Inventory Management
- Warehouse Management
- Expense Tracking
- Spend Management
- Accounts Payable
- Accounts Receivable
- Cash Flow Management
- Bank Reconciliation
- Purchase Order
- Vendor Management
- Point of Sale (POS)
- Time Tracking
- Quotation & Estimates
- Revenue Recognition
- Financial Reporting
- Asset Management
- Lead Management
- Sales Pipeline
- ERP
Also see our directory of 50 open source CRMs.