# fastify/fast-json-stringify

2x faster than JSON.stringify()

Repository: https://github.com/fastify/fast-json-stringify
Canonical: https://ross.abutalabs.com/products/fast-json-stringify
Homepage: https://npmjs.com/package/fast-json-stringify
Language: JavaScript
License: MIT
License Family: permissive
Topics: json, stringify, speed, fastify-core
Last push: 2026-08-20T02:56:38+00:00

## Health v2 (maintenance only)
Score: 92/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 80, longevity 100
- inputs: {"age_days": 3689, "days_push": 13, "days_rel": 55, "gap_med": 34, "n_releases_24m": 8}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3703, forks 224 (observed 2026-08-28T04:08:15.020033+00:00)

## What it is
A Node.js library that generates fast JSON serialization functions from JSON Schema Draft 7 definitions, significantly faster than native JSON.stringify() for small payloads. It is a Fastify core component used to speed up HTTP response serialization.

## Use cases
- serialize JSON responses faster than JSON.stringify
- generate a stringify function from a JSON schema
- speed up API response serialization in Node.js
- enforce a schema when serializing objects to JSON
- optimize serialization of small JSON payloads

## When to choose
- you have a JSON schema for your payloads and need maximum serialization speed
- you are building high-throughput Node.js HTTP services with small-to-medium payloads
- you want schema-driven, consistent JSON output

## When to avoid
- your payloads are very large, where the advantage over JSON.stringify shrinks or disappears
- you have no schema and cannot define one
- you are not in a JavaScript/Node.js environment

## Facets
- artifact type: library
- maturity: stable
- function: serialization
- domain: developer-tools, backend, performance
- platform: -
- tags: -schema, stringify, schema-based-serialization, fastify, nodejs, javascript

## Member repositories
- fastify/fast-json-stringify (main) score 92

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:15.020033+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:31:00.729324+00:00, confidence not recorded.
  - readme: https://github.com/fastify/fast-json-stringify (fetched 2026-08-28T04:08:15.020033+00:00, sha baf0355d34ff)
- Data as of 2026-08-30T08:39:29.467469+00:00.