21 releases

0.5.5 Jun 13, 2024
0.5.3 Dec 13, 2023
0.5.2 Oct 30, 2023
0.3.3 Jan 1, 2023
0.1.1 Jul 25, 2022

#101 in Text processing

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455 downloads per month
Used in 4 crates (3 directly)

Custom license

3.5K SLoC


This project is a spellchecker written completely in Rust, that maintains compatibility with the venerable Hunspell dictionary format. It is entirely native and does not rely on any other backends (Enchant, Hunspell, Aspell, etc.). This library also has the goal of being usable via WASM. Full Unicode support is baked in.

The library side has a stabalized checker, but the suggestion API is not yet finalized. The CLI is usable but not yet considered stabalized. See Feature Status for more information on what is available.

Here are some useful quick links:


This project exposes multiple interfaces to its spellchecker, listed in this section.

Command Line Interface

Just want to use this spellchecker from the command line? Check out the book, located here https://pluots.github.io/zspell/, for a more in-depth explanation of installation and usage.

If you don't want to read further, the easiest way to get started is to download a prebuilt binary from here: https://github.com/pluots/zspell/releases.

Rust Library Interface

This project also aims to create a fully functional spellchecking library, for easy programmatic use. See the documentation for the library side here https://docs.rs/zspell/. This also includes a lot of design methodology discussions, for those who are interested.

Python Interface

There is a python wrapper for this library with prebuilt wheels, available here: https://pypi.org/project/zspell/. Its source is located in the zspell-py crate.

Usage via WASM

The library API should work out of the box. Official WASM bindings will be added at some point.

Feature Status

Feature Available via Library Available via CLI Tracking Issue
Basic spellcheck functionality
Forbidden word handling #17
Morph analysis
Suggestions WIP #16
Compound word handling
Full Morph/Phone Handling WIP
Python Interface Beta N/A #18
Prebuilt WASM bindings N/A #19


This repository has the goal of highly prioritizing the most expected usage, i.e., that most words to be checked are correct. With optimizations based around this concept and with the modern computers now able to store entire compiled word lists in memory (~20 MiB), zspell tends to outperform other spellcheckers.


This library relies on features from Rust 1.65, so that is our current minimum supported version. Our CI validates this for the library and examples.

The CLI and test runner require newer features and do not keep a specific MSRV.

Test suite

This project keeps a test suite located in zspell/test-suite (symlinked to test-suite). Each file has a simple format that combines a simple affix and dictionary file. To add a test, just duplicate and edit 0-example.test.

File names are as follows:

  • 0-*: meta tests that do not get run
  • b-*: basic functionality tests
  • h-*: tests that come from the Hunspell test suite
  • i000-*: tests that address specific issues


See the LICENSE file for license information. The provided license does allow for proprietary use and adaptation; that being said, I kindly suggest that if you come up with an improvement, you submit a pull request and help us all out :)

Test suite license

Some tests are taken from Hunspell's test suite. Hunspell has various licenses, we select MPL and include a SPDX notice on relevant files.

Dictionary data license

The dictionaries provided in this repository for testing purposed have been obtained under license. These files have been sourced from here: https://github.com/wooorm/dictionaries

These dictionaries are licensed under various licenses, different from that of this project. Please see the applicable .license file withing the dictionaries/ directory.


~168K SLoC