OS	Status
Linux
macOS
Windows

This library is currently alpha‑quality. The API may evolve, internal structures may change, and edge cases are still being explored. The primary purpose of this project is for me to learn Zig by building something real, and to grow it into a reliable, well‑designed file‑type detection library over time.

If you’re interested in extending the magic table, improving the detection logic, refining the API, or helping clean up the codebase, contributions are very welcome. Suggestions, issues, and pull requests that help improve correctness, clarity, or idiomatic Zig usage are especially appreciated.

The goal of this project is to provide a dependency-free library that identifies files using heuristics similar to the file command but this is far from being a reality right now (currently, 42 out of 85 tests from the file repository fail to produce the same mime results as the ones produce by file itself).

A dependency‑free file type detection library written in Zig. It identifies files using magic numbers, lightweight heuristics, and content‑based analysis, not just extensions.

This project includes:

• A Zig library for detecting file types
• A comprehensive magic‑number table covering images, audio, video, archives, executables, documents, fonts, and more
• A tiny CLI tool for testing and debugging
• Fully cross‑platform (Windows, Linux, macOS)

• 🔍 Content‑based detection using magic numbers
• 🧠 Text vs binary heuristic for unknown formats
• ⚡ Fast: reads only the first few KB of a file
• 🧱 Zero dependencies
• 🖥️ Cross‑platform (Zig standard library)
• 🛠️ Includes a CLI tool for quick testing

The detector recognizes a wide range of formats:

PNG, JPEG, GIF, WebP, BMP, TIFF, HEIC, ICO, and more.

MP3, WAV, FLAC, OGG, AAC.

MP4, MKV, AVI, MOV, WebM.

ZIP, TAR, GZIP, BZIP2, 7Z, RAR.

PDF, DOCX/XLSX/PPTX (via ZIP magic), EPUB, SQLite.

ELF, PE (Windows), Mach‑O (macOS), Fat binaries.

TTF, OTF, WOFF, WOFF2.

WASM, SVG (text‑based), and more.

zig build

This produces a zmime executable in zig-out/bin.

./zig-out/bin/zmime path/to/file

You can add zmime to your project using zig fetch:

zig fetch --save git+https://github.com/avac74/zmime

Inside your build function:

const zmime = b.dependency("zmime", .{}).module("zmime");
exe.addModule("zmime", zmime);

You can also check the example which is a very simple CLI using the library.

const zmime = @import("zmime.zig");

pub fn main() !void {
    const info = try zmime.detectFileInfo("example.pdf");
    std.log.info("File type: {s}, MIME: {s}", .{
        @tagName(info.file_type),
        zmime.mimeToString(info.mime),
    });

    // you can also just check if a file is (likely) text or binary
    const is_test = try zmime.isTextFile(file_name);
    if (is_test) {
        std.log.info("File {s} is a text file", .{file_name});
    } else {
        std.log.info("File {s} is a binary file", .{file_name});
    }
}

This project aims to provide a fast, reliable, and extensible file‑type detection system built entirely in Zig. Below is the current roadmap, including completed features and planned enhancements.