RustPython is a Python interpreter written in Rust. RustPython can be embedded into Rust programs to use Python as a scripting language for your application, or it can be compiled to WebAssembly in order to run Python in the browser. RustPython is free and open-source under the MIT license.

• RustPython @ GitHub.

A fast, compliant alternative implementation of Python.

PyPy is a replacement for CPython. It is built using the RPython language that was co-developed with it. The main reason to use it instead of CPython is speed: it runs generally faster (see next section).

• PyPy @ Read the Docs.
• PyPy @ GitHub.

C, Just in Time!

CJIT is a lightweight C interpreter that lets you run C code instantly, without needing to build it first. Just use the executable interpreter: no extra tools, libs, or headers required. Based on Fabrice Bellard's TinyCC and inspired by Terry Davis (HolyC), CJIT brings the power of Just-In-Time execution to C programming.

• CJIT @ GitHub.

An embeddable, lightweight, secure, high-performance JavaScript engine.

Hako is a embeddable, lightweight, secure, high-performance JavaScript engine. It is a fork of PrimJS; Hako has full support for ES2019 and later ESNext features, and offers superior performance and a better development experience when compared to QuickJS.

• Hako @ GitHub.

An ECMAScript engine written in Rust.

Boa is an embeddable and experimental Javascript engine written in Rust. Currently, it has support for some of the language.

• Boa JS @ GitHub.