---
id: isbinary
version: "1.0.1"
license: BSD
license_treatment: permissive
maintenance: abandoned
---

# isbinary — Lightweight pure Python package to check if a file is binary or text.

License: permissive · Maintenance: abandoned · Downloads: 76.9K/mo

## What it is and what it does

isbinary is a lightweight pure-Python library that guesses whether a file is binary or text by examining its content using a heuristic based on Perl's pp_fttext algorithm. It uses chardet for encoding detection and has been tested against common file types (.txt, .json, .png, .jpg, etc.) and multiple encodings. The package was forked from the abandoned binaryornot project in May 2022 to add type annotations, modernize CI tooling, and drop Python 2 support.

The library solves a deceptively complex problem: naive approaches like checking for null bytes or trying to decode as UTF-8 fail on real-world files. isbinary encapsulates a battle-tested heuristic that handles edge cases across different platforms and file encodings, saving you from writing and thoroughly testing this logic yourself. However, the package itself is now abandoned—no updates since its initial release—so it will not receive bug fixes or support for newly discovered edge cases.

Use it for:

- Filter files in a directory walk to process only text files, skipping binaries like images or compiled objects.
- Validate user-uploaded files in a web application to reject binary uploads when only text is expected.
- Preprocess data pipelines to separate text and binary files for different downstream handlers.
- Build development tools that need to distinguish text source files from binary artifacts in a repository.
- Implement file-type guards in backup or sync utilities to handle text and binary files differently.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Determines whether a file is binary or text by analyzing its content using a heuristic similar to Perl's file-type detection, relying on chardet for encoding analysis.

Yes, if you need reliable binary/text detection and can accept that the package is unmaintained. It has no known vulnerabilities, low install friction, and solves a genuine problem with a proven heuristic. However, do not install if you require ongoing maintenance, support for edge cases discovered after May 2022, or compatibility with Python versions beyond 3.10—the last commit was over three years ago.

## Install

pip install isbinary
uv add isbinary
poetry add isbinary

## Installing isbinary

Before you install: Installation is straightforward with low friction. However, the package is abandoned—last release was 2022-05-22 with no updates since, though the repository remains public and the code is stable enough for basic use.

License in practice: Licensed under BSD (permissive), so you can use, modify, and distribute it freely with minimal restrictions, though the license treatment is listed as 'Other/Proprietary' in classifiers despite the BSD declaration.

Quickstart:

pip install isbinary

from isbinary.helpers import is_binary_file

if is_binary_file('path/to/file'):
    print('Binary file')
else:
    print('Text file')

Requires Python 3.8 or later (supports 3.8, 3.9, 3.10); chardet must be installed as a runtime dependency.

Verify before relying:

- Whether the heuristic handles all modern file types and encodings reliably, or if edge cases remain unresolved as the description suggests.
- Performance characteristics when analyzing large files or many files in batch.
- Compatibility with Python versions beyond 3.10, given the package is abandoned and no longer maintained.

## Package facts

- License: BSD (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: abandoned
- Downloads: 76.9K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

detect binary vs text file, file type detection python, is file binary, text file checker, binary file identification, file content analysis, encoding detection, file-detection, unmaintained

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