EByte reads a file into JSON you can edit, writes it back byte for byte, and tells you which field and which byte broke when a file doesn't match. One schema does all three. It's a Go library and a single command-line tool.
16 MiB
Largest file decoded to JSON and written back with every byte the same
1 schema
Used for reading, writing and tracing a format, so the three can't drift apart
0 modules
Outside the Go standard library. No generated code to keep in sync
Apache 2.0
License for all of the code
From the recorded test run on Linux amd64 with Go 1.27.3, one sample per case. The test logs are on GitHub.
case studies
A firmware update changes what a device sends, and the usual way to find out what changed is to capture its traffic before and after and stare at hex dumps. EByte 0.5.0 …
case studies
A PNG file is an 8-byte signature followed by chunks, and every chunk ends with a CRC-32 of its type and data. Change one byte of a comment by hand and the image is …
case studies
EByte 0.7.0 runs in a web browser. The release has a new asset, ebyte-wasm.zip, which is the same Go library compiled to WebAssembly, and the demo page on this site loads …
case studies
Every earlier case study ended with the same chore. Change the length of anything and some size field elsewhere in the file goes stale, and you fix it yourself: riff_size …
case studies
EByte 0.6.0 adds three kinds of field that real formats kept asking for. There are floating-point numbers. There are bit fields, several small numbers packed into the …
explainers
A text file explains itself. Open a CSV or a JSON file and you can read it, more or less. A binary file doesn’t. Open one in a hex editor and you see rows of …
the name
EByte is a tool that cares about bytes, every one of them, so the name starts there. The word itself is younger than most people guess, and its odd spelling was on …
case studies
BMP is about as plain as image formats get, which makes it a good test of whether a schema can describe a real file down to the last byte. This case study made a tiny …
case studies
A ZIP file is a good test of whether a schema can follow a real format’s bookkeeping. Every file inside it is described twice: once in a local header just before …
If EByte nearly fits a format you work with, or you'd like it to handle something it doesn't yet, write in.