head to head · open source
Polar vs SolidInvoice
Polar has 10,454 GitHub stars, 811 forks, 141 open issues and last shipped yesterday. SolidInvoice has 980 stars, 248 forks, 190 open issues and last shipped yesterday. Polar leads on adoption by 967% (10,454 vs 980 stars). Polar is written in Python under Apache-2.0; SolidInvoice is written in PHP under MIT. Polar has attracted 8% as many forks as stars, SolidInvoice 25%. Polar was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Polar | SolidInvoice | |
|---|---|---|
| GitHub stars | ★ 10K | ★ 980 |
| License | Apache-2.0 | MIT |
| Written in | Python | PHP |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 811 | ⑂ 248 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Polar if
- You weight community size — 10K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick SolidInvoice if
- You want the SolidInvoice feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches PHP
- You evaluated both and SolidInvoice fits your workflow better
About Polar
Website • Docs • API Reference Polar: A billing platform for the intelligence era Turn usage into revenue. Polar is the financial layer for a new generation of intelligent software, built for AI startups that need to charge for tokens, agents, and compute without building billing infrastructure from scratch. Ship any pricing model in an afternoon. Usage billing, subscriptions, seats, credits, trials, and discounts. Compose them however your product charges. Meter what matters. Bill tokens, API calls, agent runs, GPU seconds, and storage with precision down to the event. Checkouts that convert , realtime metrics…
read the full Polar overview →
About SolidInvoice
SolidInvoice The open source invoicing platform for freelancers and small businesses. Send beautiful quotes and invoices, accept online payments, automate recurring billing — and own every byte of your data. Why SolidInvoice? Most invoicing tools force a trade off: easy to use or respectful of your data. SolidInvoice gives you both. It's a mature, production ready billing platform you can run on your own server for free, or let us host for a flat $8/month — no per client limits, no surprise tiers, no lock in. Built on Symfony 7 and PHP 8.4, it's designed to be extended, integrated, and trusted. ✨ Features 💼…
read the full SolidInvoice overview →
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Frequently asked questions
Is Polar or SolidInvoice more popular?
Polar has 10,454 GitHub stars and SolidInvoice has 980. Polar has the larger community by that measure.
Are Polar and SolidInvoice free?
Both are open source. Polar is licensed under Apache-2.0 and SolidInvoice under MIT. Neither carries a licence fee.
What is the difference between Polar and SolidInvoice?
Polar is written in Python and SolidInvoice in PHP. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Polar or SolidInvoice?
Choose Polar if you want the larger community (10,454 stars) or its Apache-2.0 licence terms. Choose SolidInvoice if its feature set, stack or MIT licence fits better. Both are self-hostable.