Side by side
Brython vs J2ObjC
Both stand on code transpilers. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan AndroidiPhoneSelf-hosted+1
Brython brings Python syntax and browser APIs together for interactive web pages, with several ways to load or deploy applications. Browser security constraints and the exclusion of C-extension packages define important limits.
Visit Brython Free plan iPhoneLinuxMac
J2ObjC provides a way to bring Java non-UI code and tests into iOS projects. Its source-code requirement, platform prerequisites, and lack of shared UI support shape where it fits.
Visit J2ObjCThe facts
| Brython | J2ObjC | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | Android, iPhone, Self-hosted, Web | iPhone, Linux, Mac |
| Lowest paid plan | Not published | Free or on request |
| Plans published | None | 1 |
| Maker | Not published | Not published |
| Website | brython.info | developers.google.com |
| On code transpilers | #5 of 28 | #9 of 28 |
Brython: what it does well
- Uses Python 3 in HTML pages.
- Provides DOM access through document and window.
- Supports async and await through browser.aio.
- Can load from jsDelivr or cdnjs without installation.
- Compatible packages can be added with brython-cli.
What to know first
- Cannot use CPython packages that rely on C extensions.
- Browser limits prevent file writing through its Python interface.
- Network requests are restricted by browser rules.
J2ObjC: what it does well
- Translates Java source into Objective-C for iOS.
- Supports JUnit test translation and execution.
- Includes libraries such as Guava and Mockito.
- Free under the Apache 2.0 license.
What to know first
- No platform-independent UI toolkit.
- Requires a Mac, macOS 15+, Xcode 16+, and JDK 21+.
- Cannot convert Android binary applications.
- Developers handle memory management and may introduce leaks.
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