orjson by ijl
Fast, correct Python JSON library supporting dataclasses, datetimes, and numpy
About orjson
From the project's README at github.com/ijl/orjson. Lightly cleaned for readability; for the full source see the upstream repo.
orjson is a fast, correct JSON library for Python. It benchmarks as the fastest Python library for JSON and is more correct than the standard json library or other third-party libraries. It serializes dataclass, datetime, numpy, and UUID instances natively.
orjson.dumps() is something like 10x as fast as , serializes common types and subtypes, has a parameter for the caller to specify how to serialize arbitrary types, and has a number of flags controlling output.
orjson.loads() is something like 2x as fast as , and is strictly compliant with UTF-8 and RFC 8259 ("The JavaScript Object Notation (JSON) Data Interchange Format").
Reading from and writing to files, line-delimited JSON files, and so on is not provided by the library.
Health score breakdown
6-dimension composite. See methodology for formula and weights.
Adoption signals
Real-world usage data, pulled from each registry. The bigger the numbers, the more battle-tested the project.
| Signal | Value | Source |
|---|---|---|
| GitHub stars | 8.1k | github.com/ijl/orjson |
| GitHub forks | 303 | github.com/ijl/orjson |
| PYPI downloads (last month) | 181367k | orjson |
Release & maintenance
Is this project actively maintained, or about to die? Check the recency of last commit and last release.
| Project age | 7.5 years | since Nov 2018 |
| Last commit | 20 days ago | Apr 17, 2026 |
| Releases shipped | 148 | last: 1 months ago |
Self-hosting cost across providers
Detected requirements: 4GB RAM, 40GB disk minimum. Cheapest plan per provider that meets the requirement.
| Provider | Plan | Specs | Monthly | |
|---|---|---|---|---|
| hetzner | CAX11 | 2c · 4GB · 40GB | $4.13 USD | Deploy → |
| vultr | VC2 | 1c · 1GB · 25GB | $5 USD | Deploy → |
| linode | Nanode 1GB | 1c · 1GB · 25GB | $5.12 USD | Deploy → |
| digitalocean | Basic Regular 1GB | 1c · 1GB · 25GB | $6 USD | Deploy → |
Security advisories
GHSA-hx9q-6w63-j58v. What people say on Hacker News
- Orjson no more open issue tracker or pull requests due to signal-to-noise ratio
- Show HN: Coding Agent Session Search (Cass)
- Show HN: Typesync, schema-first Firestore tooling that now validates stored data
- You don't need advice from editors on rejected manuscripts
- Orson Scott Card on feedback from editors
Ready to self-host orjson?
Spin up a hetzner CAX11 (4GB RAM, 40GB disk) for $4.13/mo and follow the project's official install docs.
Data last refreshed May 7, 2026.
Similar open-source projects
Projects in our directory that replace the same SaaS or share topics with orjson.