# FlatBuffers

16 Hacker News commenters recommended FlatBuffers and 4 criticized it, November 2025 to November 2026. It was recommended in 5 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Fast binary serialization format that reads data without parsing, often recommended over Protocol Buffers; critics say its output can be large and bloated.

## Why people recommend it

- Fast zero-copy random access (4 comments): "easy to work with, great size (esp compressed), random access, close-to-optimal parsing, extensible" ([source](https://news.ycombinator.com/item?id=46731784)) "can be much faster. Like, faster by an arbitrarily large factor, for data at rest." ([source](https://news.ycombinator.com/item?id=46119813)) "I think it is used in many places that needs zero-copy" ([source](https://news.ycombinator.com/item?id=46731852))
- Better than Protobuf (3 comments): "ASN.1, Cap'n Proto and Flatbuffers are all more efficient and exist already." ([source](https://news.ycombinator.com/item?id=46738184)) "they might as well go to flatbuffers, which is much better than PB" ([source](https://news.ycombinator.com/item?id=46117929)) "switch to flatbuffers before you realize it's better than PB" ([source](https://news.ycombinator.com/item?id=46117925))
- Large speed gains in projects (2 comments): "FlatBuffers was definitely the majority of the improvements here!" ([source](https://news.ycombinator.com/item?id=46508422)) "outperforms Google Flatbuffers by 242x" ([source](https://news.ycombinator.com/item?id=46735090))
- Extensible, useful beyond speed (2 comments): "easy to work with, great size (esp compressed), random access, close-to-optimal parsing, extensible" ([source](https://news.ycombinator.com/item?id=46731784)) "That's something flatbuffers/capnproto do well that isn't just pure speed." ([source](https://news.ycombinator.com/item?id=46332252))

## What people warn about

- Large, bloated output and code (3 comments): "Cap’n Proto and FlatBuffers are fast but often produce rather large output" ([source](https://news.ycombinator.com/item?id=47214235)) "Flatbuffers etc. is cool but they can be very bloaty and clunky." ([source](https://news.ycombinator.com/item?id=47229807)) "Flat buffers is know to bloat client code." ([source](https://news.ycombinator.com/item?id=46509801))

## Alternatives hackers recommend

- [Protocol Buffers (protobuf)](https://hackerapproved.com/p/protocol-buffers.md): 77 recommend
- [Serde](https://hackerapproved.com/p/serde.md): 22 recommend
- [Cap'n Proto](https://hackerapproved.com/p/cap-n-proto.md): 20 recommend
- [Protobuf](https://hackerapproved.com/p/protobuf.md): 19 recommend
- [Lite³](https://hackerapproved.com/p/lite.md): 14 recommend

## Cite as

Hacker Approved, "FlatBuffers", https://hackerapproved.com/p/flatbuffers/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).