fastdiff
A fast native implementation of diff algorithm with a pure python fallback
Decision gist · record as of 2026-08-14
No. The package is abandoned with no updates since 2022 and classifiers only claim support up to Python 3.7. While the MIT license is permissive and install friction is low, the lack of maintenance means compatibility with modern Python versions and wasmer releases is uncertain. Use an actively maintained diff library instead.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires wasmer and wasmer-compiler-cranelift as runtime dependencies; WebAssembly runtime must be available on your platform.
- Low install friction with a pure-Python wheel, but the package is abandoned as of 2022 with no updates in over three years.
- The last commit was 2022-12-26 and maintenance status is marked abandoned, so expect no bug fixes or compatibility updates for modern Python versions.
License · maintenance · safety
MIT license (permissive) — MIT license is permissive and imposes no restrictions on use, modification, or distribution in your own projects.
last release 2021-05-12 (1920 days) · last repo commit 2022-12-26 · 39 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 513,819 downloads/mo, #6,243 on PyPI
Alternatives
Verify before relying
pip install fastdiff
import fastdiff
# Use fastdiff.diff() or comparable functions for text comparison- Whether the package actually works with Python versions beyond 3.7 (classifiers list only up to 3.7; requires_python is unspecified)
- Current compatibility with modern wasmer versions and whether wasmer-compiler-cranelift is still maintained
- Whether the 75x speedup claim applies to typical use cases or only specific scenarios
What it is and what it does
Fastdiff is a diff algorithm library that uses WebAssembly compiled via Wasmer to accelerate text comparison operations. It wraps a native implementation and falls back to pure Python when WebAssembly is unavailable, aiming for cross-platform compatibility. The package depends on wasmer and wasmer-compiler-cranelift to provide the WebAssembly runtime.
The package is in pre-alpha status (Development Status :: 2) and has been abandoned since late 2022 with no maintenance activity for over three years. While it carries a permissive MIT license and installs with low friction, its lack of recent updates means it may not work reliably with current Python versions or modern wasmer releases.
Use it for
- Comparing large text files or strings where performance is critical and you need faster-than-pure-Python diff operations
- Integrating diff functionality into applications where cross-platform WebAssembly acceleration is preferred over native C extensions
- Testing or prototyping WebAssembly-based algorithm implementations in Python environments
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
No.
The package is abandoned with no updates since 2022 and classifiers only claim support up to Python 3.7. While the MIT license is permissive and install friction is low, the lack of maintenance means compatibility with modern Python versions and wasmer releases is uncertain. Use an actively maintained diff library instead.
Install
fastdiff on PyPI
Before you install
Low install friction with a pure-Python wheel, but the package is abandoned as of 2022 with no updates in over three years. The last commit was 2022-12-26 and maintenance status is marked abandoned, so expect no bug fixes or compatibility updates for modern Python versions.
Requires wasmer and wasmer-compiler-cranelift as runtime dependencies; WebAssembly runtime must be available on your platform.
License in practice
MIT license is permissive and imposes no restrictions on use, modification, or distribution in your own projects.
Quickstart
pip install fastdiff
import fastdiff
# Use fastdiff.diff() or comparable functions for text comparisonVerify before relying
- Whether the package actually works with Python versions beyond 3.7 (classifiers list only up to 3.7; requires_python is unspecified)
- Current compatibility with modern wasmer versions and whether wasmer-compiler-cranelift is still maintained
- Whether the 75x speedup claim applies to typical use cases or only specific scenarios
Package facts
| License | MIT license permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 2 packageswasmerwasmer-compiler-cranelift |
| Maintenance | Abandoned 1,920 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 513,819 / month, #6,243 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 2 - Pre-AlphaIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseNatural Language :: EnglishProgramming Language :: Python :: 2Programming Language :: Python :: 2.7Programming Language :: Python :: 3Programming Language :: Python :: 3.4Programming Language :: Python :: 3.5Programming Language :: Python :: 3.6Programming Language :: Python :: 3.7 |
Evidence: fastdiff-0.3.0-py2.py3-none-any.whl
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See also cdifflib · collate-data-diff · cydifflib · rpm-vercmp · wasmer-compiler-cranelift · wasmer · diff-match-patch · merge3 · file-read-backwards · jsondiff