# devinus/poison

An incredibly fast, pure Elixir JSON library

Repository: https://github.com/devinus/poison
Canonical: https://ross.abutalabs.com/products/poison
Language: Elixir
License: 0BSD
License Family: permissive
Topics: elixir, elixir-libraries, json, json-library, json-parser
Last push: 2024-08-12T12:23:55+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4532, "days_push": 751, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2030, forks 214 (observed 2026-08-28T04:06:07.160559+00:00)

## What it is
Poison is a fast, pure-Elixir JSON encoding and decoding library that fully conforms to RFC 8259 and ECMA 404. It provides a hand-rolled single-pass parser, IO list encoding, and struct-aware encoding/decoding via the Poison.Encoder protocol.

## Use cases
- encode elixir maps and structs to
- decode  strings into elixir maps
- parse  with atom keys
- decode  directly into structs
- fast  parsing for phoenix apis

## When to choose
- you need a pure-Elixir JSON library with no native dependencies
- you want RFC 8259-compliant JSON handling in Elixir
- you need struct encoding/decoding via protocols

## When to avoid
- you prefer the built-in Jason library already common in the ecosystem
- you need NIF-based maximum throughput like jiffy

## Facets
- artifact type: library
- maturity: stable
- function: serialization, parser
- domain: developer-tools, apis, web-development
- platform: elixir, jvm
- tags: elixir, encoder, decoder, rfc8259

## Member repositories
- devinus/poison (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:07.160559+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 2026-08-30T02:59:35.314807+00:00, confidence not recorded.
  - readme: https://github.com/devinus/poison (fetched 2026-08-28T04:06:07.160559+00:00, sha 42915e4f3936)
- Data as of 2026-08-30T08:39:29.467469+00:00.