HN Showcase
Back to browse
Fbsviewer – FlatBuffers binary viewer. Pure Rust compiler in WASM

Fbsviewer – FlatBuffers binary viewer. Pure Rust compiler in WASM

by SuzyLi·Mar 6, 2026·4 points·1 comment
Visit ProjectView on HN

AI Analysis

●●SolidNiche GemWizardry

Linked hex and schema view makes FlatBuffers binary encoding finally human-readable.

Strengths
  • •Full Rust compiler compiled to WASM means zero dependencies and instant offline access in browser
  • •Dual-view design (bytes ↔ structure) elegantly solves the core friction point of opaque binary debugging
  • •JSON output generation from schema closes the gap between wire format and developer intuition
Weaknesses
  • •Ultra-niche audience: only matters if you're already using FlatBuffers at scale
  • •No import/export features for test data generation, limiting usefulness beyond one-off debugging
Target Audience

Backend engineers debugging serialization issues or learning FlatBuffers format; performance-focused teams using FlatBuffers for data interchange.

Post Description

I built fbsviewer, an interactive tool to help understand how FlatBuffers binaries are encoded.

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.

Similar Projects

Infrastructure●Mid

OxiMedia – Pure Rust Reconstruction of FFmpeg and OpenCV

1.36M LOC pure Rust reimplementation—v0.1.0, APIs stabilized, perf unproven.

Bold BetWizardry
kitasan
11113mo ago