ultrajson/ultrajson
Some data may be outdated — see provenance labels.
Ultra fast JSON decoder and encoder written in C with Python bindings observed · 2026-10-02
Health v2 · maintenance only
92/100
- Activity 97
- Release rhythm 81
- Longevity 100
Flags: no_license
How is this computed?
round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-10-22. Adoption (stars, forks) is never an input.
- gap_med: 67.5
- age_days: 5715
- days_rel: 48
- days_push: 20
- n_releases_24m: 5
Adoption not part of the score
4499 stars · 386 forks observed · 2026-10-02
What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded
UltraJSON (ujson) is an ultra-fast JSON encoder and decoder written in pure C with Python bindings, usable as a drop-in replacement for the standard json module. It is now in maintenance-only mode, with users encouraged to migrate to orjson.
Use cases
- speed up json serialization in python
- fast json parsing for large payloads
- drop-in replacement for python json module
- encode json with html-safe escaping
- decode json faster than stdlib
When to choose
- you need faster JSON encoding/decoding than the Python standard library and cannot use orjson
- you have an existing codebase already depending on ujson
When to avoid
- starting a new project - the maintainers recommend orjson instead
- you need new features or non-critical bug fixes, since only critical/security issues are accepted
Facets
library · maturity maintenance
serialization parser developer-tools backend python cross-platform json c-extension ujson encoder decoder performance data-engineering
2 sources
- readme: https://github.com/ultrajson/ultrajson · fetched 2026-10-02 · 32db61660b07
- homepage: https://pypi.org/project/ujson/ · fetched 2026-08-29 · 4b4e8fead74a
Member repositories
| Repository | Role | Health v2 |
|---|---|---|
| ultrajson/ultrajson | main | 92 |
For agents
markdown · JSON · MCP: product_card(name="ultrajson/ultrajson")
Data as of 2026-10-19T08:05:51.212177+00:00 · Report a problem