# thoughtbot/Argo

Functional JSON parsing library for Swift

Repository: https://github.com/thoughtbot/Argo
Canonical: https://ross.abutalabs.com/products/argo
Homepage: https://thoughtbot.com
Language: Swift
License: MIT
License Family: permissive
Last push: 2021-09-24T16:03:36+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4363, "days_push": 1804, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3471, forks 193 (observed 2026-08-28T04:08:05.970781+00:00)

## What it is
Argo is a functional JSON parsing library for Swift that extracts type-safe models from JSON with explicit failure states. It was inspired by the Haskell Aeson library and uses Swift's type system to eliminate manual validation code.

## Use cases
- parse json into swift models
- type-safe json decoding in ios app
- avoid writing manual json validation code
- functional json parsing library for swift
- map api responses to model objects
- handle missing or mistyped json fields gracefully

## When to choose
- you want concise, type-safe JSON-to-model decoding in Swift
- you prefer a functional programming style with explicit failure states
- you're on an older Swift codebase already using Argo or Runes

## When to avoid
- you're starting a new project - Swift's built-in Codable covers most needs
- you need a library actively updated for the latest Swift versions
- you want JSON decoding without functional programming dependencies like Runes or Curry

## Facets
- artifact type: library
- maturity: maintenance
- function: serialization, parser
- domain: developer-tools, mobile-development, parsers
- platform: -
- tags: json-parsing, functional-programming, type-safe, decodable, swift, ios, macos

## Member repositories
- thoughtbot/Argo (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:05.970781+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 2026-08-29T18:36:38.302531+00:00, confidence not recorded.
  - readme: https://github.com/thoughtbot/Argo (fetched 2026-08-28T04:08:05.970781+00:00, sha f5df80c87413)
  - homepage: https://thoughtbot.com (fetched 2026-08-29T09:30:36.467450+00:00, sha 5510254df796)
  - site_page: https://thoughtbot.com/case-studies/closeknit-health (fetched 2026-08-29T09:30:36.470179+00:00, sha ec773542ed58)
  - site_page: https://thoughtbot.com/services (fetched 2026-08-29T09:30:36.472150+00:00, sha 5b152b8c27da)
  - site_page: https://thoughtbot.com/our-company (fetched 2026-08-29T09:30:36.473846+00:00, sha 9e2e18b981fb)
- Data as of 2026-08-30T08:39:29.467469+00:00.