You're about to ship your Python desktop application. You've built it with PyQt because it's the most capable GUI framework in the ecosystem. The app works perfectly. You're ready to sell it.
Then someone mentions licensing.
Suddenly you're reading through GPL provisions, trying to figure out if LGPL applies (it doesn't to PyQt), and realizing that "free to use" has some very significant asterisks.
The Quick Answer
If you're building closed-source commercial software with PyQt, you need a commercial license.
| License Type | Price | Coverage |
|---|---|---|
| Qt for Application Development | €550/month/dev | Full Qt + PyQt |
| Small Business (<€250k revenue) | €45/month/dev | Limited support |
| Startup Program | Free (1 year) | For qualifying startups |
Annual commitment required. That's €6,600/year for a single developer. For a team of three, you're looking at nearly €20,000/year just in licensing.
Why Does PyQt Require a License?
PyQt uses a dual-license model: GPL and Commercial.
GPL (Free):
- Your entire application must be open-source
- You must release your source code under GPL
- Anyone can view, modify, and redistribute your code
Commercial (Paid):
- Keep your code proprietary
- No requirement to release source
- Required for any closed-source use
There's a common misconception that if you're "just using" PyQt and not modifying it, you're fine. That's not how GPL works. If your application links to PyQt, your application becomes a derivative work.
But What About PySide6?
Here's where it gets interesting. PySide6 is the official Python binding for Qt, maintained by The Qt Company themselves, and it uses LGPL licensing.
LGPL Allows You To:
- Use PySide6 in closed-source commercial software
- Distribute your application without releasing source code
- Not pay licensing fees
Why does PyQt cost money and PySide6 doesn't?
PyQt is developed by Riverbank Computing, a separate company that monetizes through commercial licenses. PySide6 is developed by The Qt Company, who make money from underlying Qt framework licensing for C++ developers.
The functionality is nearly identical. The licensing is completely different.
Real-World Cost Scenarios
Scenario 1: Solo Developer Building a $50 App
- PyQt: €6,600/year = 132 sales just to break even on licensing
- PySide6: €0
- Recommendation: Use PySide6 or don't use Qt at all
Scenario 2: Startup with 3 Developers
- PyQt: €19,800/year
- PySide6: €0 (but loses some enterprise support)
- Recommendation: Use PySide6, apply for Qt Startup Program
Scenario 3: Enterprise, Mission-Critical App
- PyQt: €66,000/year for 10 developers
- Recommendation: Pay for proper licensing. Support and stability matter.
Alternatives to Consider
PySide6 (Free, LGPL)
Same Qt power, different license. For most commercial projects, this is the obvious choice. The API is 95% identical to PyQt.
wxPython (Free, wxWindows License)
Truly free for commercial use. Native look and feel. Less powerful than Qt, but zero licensing concerns.
CustomTkinter (Free, MIT)
Modern appearance on top of Tkinter. Limited capability compared to Qt, but zero cost.
Bravura (Flexible Pricing)
Commercial framework designed for professional applications. Starts at $49.99/month or $1,999.99 one-time. No per-developer fees—one license covers your team.
My Honest Take
If you're committed to Qt and have enterprise budget, pay for proper licensing. The support is worth it for mission-critical applications.
If you're a solo developer, small team, or startup—just use PySide6. The functionality is the same. The license is free for commercial use.
If you don't specifically need Qt's advanced features, consider whether you need Qt at all. Simpler frameworks work fine for most applications and come with zero licensing overhead.
Frequently Asked Questions
Q: Can I use PyQt commercially if I'm not selling the app?
A: If you're distributing closed-source software (even internally), you need a license. "Commercial" doesn't mean "sold"—it means "not GPL."
Q: What happens if I get audited?
A: You'll need to purchase licenses retroactively (potentially with penalties) or open-source your application under GPL.
Q: Can I switch from PyQt to PySide6 mid-project?
A: Yes. The APIs are very similar. There's a compatibility layer called qtpy that abstracts the differences.
Conclusion
PyQt commercial licensing costs €6,600+/year per developer. For some projects, that's reasonable. For others, it's a dealbreaker.
The good news: you have options. PySide6 gives you the same Qt power with LGPL licensing. Other frameworks avoid the Qt ecosystem entirely.
Whatever you choose, understand the licensing before you ship.