AI that finds the fastest version of your Python code, then proves it still behaves the same.
Codeflash is an AI performance engineer for your Python code. It profiles your functions, finds the ones that are actually slow, rewrites them, and verifies the rewrite returns the same results before you accept it. The focus is Python, where it reports average runtime cuts of around 50%, with JavaScript, Java, and C++ supported too.
What sets it apart from a general code assistant is that it measures first and checks its work. Instead of guessing, it benchmarks your function, targets the real hotspot, and tests every change against the original so a speed-up can't quietly alter behavior. That makes it a strong fit for working developers and data teams who care about runtime and cost, and a poor fit if what you want is Copilot-style code generation.
def slow_sum(numbers):
total = 0
for num in numbers:
total += num * 2
return total
import numpy as np
def fast_sum(numbers):
return np.sum(np.array(numbers) * 2)
Benchmarks your functions to find the real hotspots instead of guessing where time goes.
Every optimization is tested against the original, so refactors can't quietly change behavior.
A VS Code plugin flags slow sections in real time as you write, with inline explanations.
Preview the impact before applying: a query rewrite that cuts SQL calls by 40%.