The fastest way to understand binary files

Hex editor for Mac BoxShot

Imagine... you have a binary file and don't know its contents. Or some software creates binary files you have a specification for but don't want to decode them manually.

Have you ever looked at hex dumps and felt how hard it is to make sense of it? And to remember the meaning of all the bits and bytes?

Synalyze It! allows you to create a “grammar“ for your binary files interactively. Unlike in regular hex editors or viewers the files are interpreted automatically for you! Analysis of binary files has never been easier.

Hex Editor for Mac

Additionally Synalyze It! is a full-featured Hex Editor for Mac OS X allowing you to edit files of unlimited size and interpret the bytes with dozens of text encodings.

Synalyze It! Hex Editor for Mac Screenshot

Essentially its a modeling tool for arbitrary file formats that is being used by software developers and data stream experts as well as in computer forensics.

The grammars are stored as XML files and contain all the structures that may occur in a file of a certain format, just like XML schemas. Its even possible to inherit structures from others (like in OO languages) so you don't have to repeat for example a length field that appears at the beginning of each structure.

Analysis Tool and Hex Editor for Mac

Synalyze It! is an extremely flexible and useful tool for viewing binary file data. It enables you to easily apply a structured format to your file bytes and convert them into meaningful displays of data.

Synalyze It! provides formatters for common binary types like ICC, PNG, TIFF, WAV, ZIP and dozens more. That alone is useful but, if you’re a programmer creating a custom binary file format, Synalyze It! is priceless. 

With Synalyze It!, you can create custom data formatters for your personal binary files. Instead of struggling with cryptic lines of hexadecimal, you can view and label data values as floating point or integer, signed or unsigned, with any byte length. Your files can even modify the formatting, allowing you to create settings on the fly to variably view your data.

If the standard formatting tools are not enough, you can write formatting scripts using Python or Lua. I quickly got ambitious and was soon in over my head exploring Synalyze It!’s features. When I emailed a question to the developer, the technical support was outstanding. I was sent a complete solution to my problem that also served as an advanced Synalyze It! tutorial.

I doubt that I will ever fully exploit the potential of Synalyze It! but the value I’ve received is already many multiples of the price I paid.

John Goodman

For some well-known formats you can download grammars here. Matching grammars are suggested automatically when you open a file.

Right now you can download Synalyze It! for Mac OS X and give it a try. In case of questions or problems please give me feedback. The latest changes can be tracked here; stay tuned also on Twitter.

If you like Synalyze It! consider buying the Pro version in the Mac App Store.
The Pro version has even more useful features beyond hex editing.


I just bought the pro version of Synalyze, and I am very glad I did. Thank you for taking the time to bring this excellent tool to life.

I’m the author of an open-source program called SleepyHead, which is used for reviewing CPAP machine data (used in Sleep Apnea treatment), and already I’m wishing I discovered Synalyze a lot sooner, as an awful lot of binary format hacking is involved thanks to the manufacturers not releasing documentation.

I particularly like being able to use expressions in the length fields.. I spent ages looking through the example grammar and scripts only to find I didn’t even need them thanks to this feature. (It pays to read the manual first.. ;)

Keep up the good work!


Mark Watkins

Mac Hex Editor for Professionals

Beyond Hex Editing

There are some hex editors for Mac available but only Synalyze It! allows to create a grammar for automatic file decoding in a specialized grammar editor.

  1. Simply open the file you want to analyze
  2. Create an empty grammar
  3. Select bytes in the hex editor and add an element or structure to the grammar using the context menu
  4. Enhance the grammar in the grammar editor
processing files using grammars

Other special features of Synalyze It!:

  • Supports various encodings like ASCII, EBCDIC, UTF-8 or UTF-16 (see ICU for all supported encodings)
  • Lets you easily see if a file is compressed with the histogram view
  • Opens even huge files ultra fast by loading only the visible part of a file
  • Hex editing works with the same mouse and keyboard commands like in common text editors

In case you need a tool specialized in disk editing, I recommend to check out iBored.

Recent updates:

2022-08-24: Version 1.26 supports Apple Silicon natively and includes Python 3.10
2020-01-05: Added grammar for Commander Keen 1-3 saved games
2019-09-13: Version 1.23 released with dark mode support
2019-05-16: Added grammar for Ducati Data Analyzer dda files (thank you, Jack!)
2019-02-17: Added grammar for Atari Lynx .lnx files (thank you, Brian!)
2019-02-14: Added grammar for uImage files on Linux (thank you, Lukas!)

Older additions to the web site can be found here…