# zserge/jsmn

Jsmn is a world fastest JSON parser/tokenizer. This is the official repo replacing the old one at Bitbucket

Repository: https://github.com/zserge/jsmn
Canonical: https://ross.abutalabs.com/products/jsmn
Language: C
License: MIT
License Family: permissive
Topics: json-data, json-string, parsing
Last push: 2024-06-09T11:29:26+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 3985, "days_push": 815, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4175, forks 814 (observed 2026-08-28T04:08:38.171374+00:00)

## What it is
jsmn is a minimalistic, header-only JSON parser/tokenizer written in C89 with no dependencies and no dynamic memory allocation. It produces tokens that point into the original JSON string, enabling zero-copy parsing in resource-constrained environments.

## Use cases
- parse json in c without dynamic memory allocation
- embed a tiny json parser in a microcontroller project
- tokenize json strings with zero-copy semantics
- parse json on avr or arm with minimal footprint
- validate json structure in an embedded firmware
- add json parsing to a c89 codebase with no dependencies

## When to choose
- you need an extremely small, dependency-free JSON parser in C
- your target is resource-limited or embedded and cannot afford heap allocation
- you want a simple tokenizer that points into the original buffer
- portability across x86, ARM, and AVR matters

## When to avoid
- you need a full DOM with value extraction by key out of the box
- you require JSON validation with detailed error reporting
- you need support for very large or deeply nested documents without preallocating token arrays
- you want a parser in a higher-level language with richer APIs

## Facets
- artifact type: library
- maturity: maintenance
- function: parser, serialization, json
- domain: parsers, developer-tools, embedded-systems
- platform: c, cpp, embedded, cross-platform
- tags: header-only, zero-copy, no-heap-allocation, tokenizer, c89, single-header

## Member repositories
- zserge/jsmn (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:38.171374+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 2026-08-29T18:22:42.735915+00:00, confidence not recorded.
  - readme: https://github.com/zserge/jsmn (fetched 2026-08-28T04:08:38.171374+00:00, sha 9b052f4d2110)
- Data as of 2026-08-30T08:39:29.467469+00:00.