Mojo🔥 is now open source

Simon Willison’s Weblog

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18th August 2026 - Link Blog

Mojo🔥 is now open source (via) The Mojo programming language has been promising an open source release since May 2023. Last week they shipped their 1.0 and today they have followed through on that original promise, releasing the compiler and toolchain under an Apache 2 license.

When Mojo first launched the stated goal was to produce a superset of Python, so existing Python code could be used to bootstrap their own ecosystem. That plan changed around August 2025:

Mojo may or may not evolve into a full superset of Python, and it’s okay if it doesn’t.

We’re encouraged by how well AI-assisted coding tools already help migrate Python to Mojo today, and we’re confident that future tooling and ecosystem maturity will make this evolution even smoother.

Today Mojo is its own language, optimized to make GPU programming as painless as possible using syntax inspired by Python, if not 100% compatible with existing code.

Posted 18th August 2026 at 9:39 pm

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This is a link post by Simon Willison, posted on 18th August 2026.

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