nlohmann/json
JSON for Modern C++ observed · 2026-08-28
Health v2 · maintenance only
67/100
- Activity 99
- Release rhythm 8
- Longevity 100
How is this computed?
round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-02. Adoption (stars, forks) is never an input.
- gap_med: n/a
- age_days: 4808
- days_rel: 509
- days_push: 8
- n_releases_24m: 1
Adoption not part of the score
50471 stars · 7479 forks observed · 2026-08-28
What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded
A header-only C++ library providing JSON parsing, serialization, and manipulation with an intuitive STL-like API. It supports JSON Pointer, JSON Patch, JSON Merge Patch, and binary formats such as CBOR, MessagePack, UBJSON, BJData, and BSON.
Use cases
- parse from a string or file in c++
- serialize c++ structs to
- convert to cbor or messagepack
- apply patch to a document
- read config files as in c++
- build and modify objects with stl-like syntax
- deserialize into custom types
When to choose
- you need a mature, widely-used, header-only JSON library for C++
- you want intuitive STL-container-like JSON manipulation
- you need binary JSON-like formats (CBOR, MessagePack, UBJSON, BSON, BJData)
- you need RFC-compliant JSON Pointer, Patch, and Merge Patch support
When to avoid
- you need maximum parsing performance (consider simd)
- you need relaxed JSON parsing such as trailing commas or comments by default
- you work in a language other than C++
Facets
library · maturity stable
serialization parser developer-tools apis files cpp cross-platform windows header-only -pointer -patch cbor messagepack ub bson bjdata stl-containers rfc-8259 linux macos
10 sources
- readme: https://github.com/nlohmann/json · fetched 2026-08-28 · 5599c2ccae7b
- homepage: https://json.nlohmann.me · fetched 2026-08-28 · 8f732461812b
- site_page: https://json.nlohmann.me/features/ · fetched 2026-08-28 · e4ad9ef7b1c0
- site_page: https://json.nlohmann.me/features/arbitrary_types/ · fetched 2026-08-28 · 6fceb60563f4
- site_page: https://json.nlohmann.me/features/binary_formats/ · fetched 2026-08-28 · e3f478842697
- site_page: https://json.nlohmann.me/features/binary_formats/bjdata/ · fetched 2026-08-28 · dcbec842d3ed
- site_page: https://json.nlohmann.me/features/binary_formats/bson/ · fetched 2026-08-28 · d573d957b2ee
- site_page: https://json.nlohmann.me/api/basic_json/ · fetched 2026-08-28 · 23d6f074732b
- site_page: https://json.nlohmann.me/home/faq/ · fetched 2026-08-28 · 62ddf9125ffd
- site_page: https://json.nlohmann.me/home/releases/ · fetched 2026-08-28 · 308e00925993
Member repositories
| Repository | Role | Health v2 |
|---|---|---|
| nlohmann/json | main | 67 |
For agents
Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem