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ijl/orjson

Fast, correct Python JSON library supporting dataclasses, datetimes, and numpy observed · 2026-08-28

github.com/ijl/orjson · Python · Apache-2.0 (permissive) observed · 2026-08-28

Health v2 · maintenance only

98/100

  • Activity 98
  • Release rhythm 98
  • Longevity 100
How is this computed?

round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-03. Adoption (stars, forks) is never an input.

  • gap_med: 21
  • age_days: 2842
  • days_rel: 19
  • days_push: 13
  • n_releases_24m: 22

Full methodology

Adoption not part of the score

8214 stars · 327 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

orjson is a fast, correct JSON serialization/deserialization library for Python, implemented in Rust via PyO3. It natively serializes dataclasses, datetimes, numpy arrays, and UUIDs, and benchmarks significantly faster than the standard json library.

Use cases

  • serialize json faster than the standard library
  • serialize dataclasses and datetimes to json
  • serialize numpy arrays to json
  • parse json strictly per RFC 8259
  • speed up json encoding in a python api
  • dump json with uuid support

When to choose

  • you need maximum JSON serialization/deserialization performance in CPython
  • you need native serialization of dataclasses, datetimes, numpy arrays, or UUIDs
  • you need strict RFC 8259 and UTF-8 compliance

When to avoid

  • you need file or line-delimited JSON I/O helpers
  • you use PyPy, embedded Python on Android/iOS, or subinterpreters
  • you need a pure-Python dependency

Facets

library · maturity stable

serialization parser developer-tools apis python windows json rust pyo3 performance dataclasses numpy datetime data-engineering linux macos

1 source

Member repositories

RepositoryRoleHealth v2
ijl/orjsonmain98

For agents

markdown · JSON · MCP: product_card(name="ijl/orjson")

Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem