Jiwer

Jiwer is a simple and fast Python package designed to evaluate Automatic Speech Recognition (ASR) systems. It computes similarity measures such as Word Error Rate (WER), Match Error Rate (MER), Word Information Lost (WIL), Word Information Preserved (WIP), and Character Error Rate (CER). It uses RapidFuzz, which leverages C++ under the hood, for efficient minimum-edit distance calculations, making it faster than pure Python implementations. The current version is 4.0.0, released in June 2025, and it maintains an active development and release cadence.