FlatBuffers is designed for performance and zero-copy access, but that also makes the raw binary format hard to reason about. When debugging serialization issues or learning the format, I often found it difficult to connect the schema, decoded data, and the underlying bytes.

This tool lets you paste a .fbs schema and some hex-encoded FlatBuffers data and see how the bytes map to tables, fields, vectors, strings, and vtables. The hex view and structure view are linked so you can move between the raw bytes and the logical structure.

A few things it includes:

- Color-coded hex view showing how bytes map to FlatBuffers structures

- Interactive structure tree linked to byte ranges

- Decoded JSON view generated from the schema

- FlatBuffers schema compiler running in WebAssembly, so everything runs fully in the browser

I originally built it to debug serialization issues, but it also turned out to be a useful way to understand how FlatBuffers encoding works internally.

You can try it here: https://fbsviewer.shuozeli.com

Repo: https://github.com/Shuozeli/fbsviewer-lib

Feedback and suggestions are very welcome.