Work · alternatives · 2026

24 alternatives to fastgron: A JSON to GRON Converter That's 40 Times Faster Than Gron

Hello HN! I want to introduce fastgron, my new project. fastgron is a JSON to GRON converter, built to be incredibly fast – it's 40 times faster than Gron. GRON is a tool for making JSON greppable, but it can slow down with larger files. With fastgron, even a 200MB JSON file can be converted in just 1 second. Key features include streaming conversion for memory efficiency and an optimized path reconstruction for faster operations. It leverages C++ and the simdjson and fast_io libraries for speed. I welcome all feedback, suggestions, or questions. Thank you!

fastgron converts JSON files into GRON format, which makes JSON data greppable for easier searching and filtering. Built in C++ using optimized libraries, it handles large files efficiently through streaming conversion… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. fastgron: A JSON to GRON Converter That's 40 Times Faster Than Gron launched in 2023; newer entries below may have overtaken it.

1
ffjson: faster json serialization in Go▲83
2014 · journal.paul.querna.org · its alternatives →
2
A fast JSON library for Go▲119
Fast JSON encoder/decoder compatible with encoding/json for Go - goccy/go-json
2021 · github.com · its alternatives →
3
fastjson - Fast JSON Parsing for Go▲20
Fast JSON parser and validator for Go. No custom structs, no code generation, no reflection - valyala/fastjson
2018 · github.com · its alternatives →
4
Faster FastAPI with simdjson and io_uring on Linux 5.19▲290
A few months ago, I benchmarked FastAPI on an i9 MacBook Pro. I couldn't believe my eyes. A primary REST endpoint to `sum` two integers took 6 milliseconds to evaluate. It is okay if you are targeting a server in another city, but it should be less when your client and server apps are running on the same machine. FastAPI would have bottleneck-ed the inference of our lightweight UForm neural networks recently trending on HN under the title "Beating OpenAI CLIP with 100x less data and compute". (Thank you all for the kind words!) So I wrote another library. It has been a while since I have…
2023 · github.com · its alternatives →
5
Gojay – Performant JSON encoder/decoder for Golang▲153
high performance JSON encoder/decoder with stream API for Golang - GitHub - francoispqt/gojay: high performance JSON encoder/decoder with stream API for Golang
2018 · github.com · its alternatives →
6
Fast.js – faster reimplementations of native JavaScript functions▲323
Faster user-land reimplementations for several common builtin native JavaScript functions. - codemix/fast.js
2014 · github.com · its alternatives →
7
A Fast, Malloc-Free C++14 Json Parser and Encoder▲98
Meta programming utilities for C++14. Merged in matt-42/lithium - matt-42/iod
2014 · github.com · its alternatives →
8
Python JSON library in Rust, faster than ujson▲40
Fast, correct Python JSON library supporting dataclasses, datetimes, and numpy - ijl/orjson
2018 · github.com · its alternatives →
9
Fast 2kB date library alternative to Moment.js with the same API▲122
⏰ Day.js 2kB immutable date-time library alternative to Moment.js with the same modern API - iamkun/dayjs
2018 · github.com · its alternatives →
10
Cyjson – Fast and Efficent JSON Parser for Python▲10
2015 · github.com · its alternatives →
11
Faster.js – a micro-optimizing JavaScript compiler▲89
faster.js is a Babel plugin that compiles idiomatic Javascript to faster, micro-optimized Javascript. - vzhou842/faster.js
2018 · github.com · its alternatives →
12
PJSON.live▲15
Format, validate & convert json to typescript instantly
Nov 2025 · pjson.live · its alternatives →
13JA
JSON as Fast as Binary▲12
2015 · hperadin.github.io · its alternatives →
14
Go Struct to JSON Converter▲7
Instantly turn Go structs into AI-mocked JSON
2025 · its alternatives →
15
Quick JSON Formatter▲72
Quickly formats JSON with a simple right click, no copy
2023 · chromewebstore.google.com · its alternatives →
16
My first open-source project release – RandomJson▲56
Provides a Kotlin/Java library to create a random json string - mangatmodi/RandomJson
2019 · github.com · its alternatives →
17
Gojay – highly performant JSON encoder/decoder for Golang▲11
high performance JSON encoder/decoder with stream API for Golang - GitHub - francoispqt/gojay: high performance JSON encoder/decoder with stream API for Golang
2018 · github.com · its alternatives →
18
StaticJSON: fast, direct and static typed parsing of JSON with C++▲18
Fast, direct and static typed parsing of JSON with C++ - netheril96/StaticJSON
2016 · github.com · its alternatives →
19
bote - A fast, modern and low-memory approach to processing a big JSON▲5
A fast, modern and low-memory approach to processing a big JSON - jankdc/bote
Jun 2026 · github.com · its alternatives →
20
The fastest JSON parser for Go▲7
THE fastest alternative JSON parser for Go that does not require schema - buger/jsonparser
Jul 2026 · github.com · its alternatives →
21
SJSON – a fast and simple way to set a value in JSON▲11
Set JSON values very quickly in Go. Contribute to tidwall/sjson development by creating an account on GitHub.
2016 · github.com · its alternatives →
22
JSON Minifier: Fast & Secure▲3
Compress JSON data instantly for faster web performance.
Feb 2026 · 99tools.net · its alternatives →
23
Jsong: faster than light streaming JSON parser and writer in C▲9
2017 · github.com · its alternatives →
24
Streaming JSON in Rust▲7
Terabytes of JSON, kilobytes of memory
Jan 2026 · github.com · its alternatives →

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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →