Python 3.15's JIT finally beats the standard interpreter

How Fast is Python 3.15?

Miguel Grinberg benchmarks Python 3.15 against versions back to 3.10, plus PyPy, Node.js, and Rust, using recursive Fibonacci and bubble sort tests. The standard interpreter shows only marginal gains over 3.14, but the JIT variant delivers a 1.20x speedup on Fibonacci and 1.28x on bubble sort—the first time the JIT outperforms the standard interpreter. Free-threading remains comparable to 3.14, while PyPy and Rust still dominate overall.