# scalalandio/chimney

Scala library for boilerplate-free, type-safe data transformations

Repository: https://github.com/scalalandio/chimney
Canonical: https://ross.abutalabs.com/products/chimney
Homepage: https://chimney.readthedocs.io
Language: Scala
License: Apache-2.0
License Family: permissive
Topics: scala, boilerplate, generic-programming, automatic-conversion, auto-mapping, data-rewriting, scala-library, conversion, transformation, derivation, jvm, metaprogramming, scala-native, scala3, scalajs, macros, type-mapping, contributors-welcome
Last push: 2026-09-02T11:01:50+00:00

## Health v2 (maintenance only)
Score: 93/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 81, longevity 100
- inputs: {"age_days": 3389, "days_push": 0, "days_rel": 50, "gap_med": 44, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1254, forks 113 (observed 2026-09-03T02:15:17.684284+00:00)

## What it is
Chimney is a battle-tested Scala library for boilerplate-free, type-safe data transformations between case classes and other types. It uses macro-based derivation to automatically generate conversion code, supporting Scala 2.13 and 3 across JVM, Scala.js, and Scala Native.

## Use cases
- convert between case classes without writing boilerplate
- map DTOs to domain objects in Scala
- automatically derive type-safe object transformations
- patch and update immutable data structures
- migrate between versions of a data model
- reduce manual mapping code in Scala applications

## When to choose
- you need type-safe, compile-time-checked transformations in Scala
- you want to eliminate manual field-by-field mapping code
- you need cross-platform support (JVM, Scala.js, Scala Native)
- you want a mature library with production adopters

## When to avoid
- you are not using Scala
- you need runtime-configurable (dynamic) mapping rather than compile-time derivation
- your transformations involve complex runtime logic macros cannot express

## Facets
- artifact type: library
- maturity: stable
- function: serialization, developer-tools, plugin-system
- domain: developer-tools, programming-languages
- platform: jvm, cross-platform
- tags: scala, data-transformation, boilerplate-free, type-safe, macro-derivation, object-mapping, scala-native, scala-js, scala-3, metaprogramming, automation

## Member repositories
- scalalandio/chimney (main) score 93

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:17.684284+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 2026-08-30T05:07:21.227942+00:00, confidence not recorded.
  - readme: https://github.com/scalalandio/chimney (fetched 2026-09-03T02:15:17.684284+00:00, sha 8d27781bb1de)
- Data as of 2026-08-30T08:39:29.467469+00:00.