# Kotlin/kotlinx.serialization

Kotlin multiplatform / multi-format serialization

Repository: https://github.com/Kotlin/kotlinx.serialization
Canonical: https://ross.abutalabs.com/products/kotlinxserialization
Language: Kotlin
License: Apache-2.0
License Family: permissive
Topics: kotlin, serialization, json, cbor, protobuf
Last push: 2026-08-24T10:47:54+00:00

## Health v2 (maintenance only)
Score: 88/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 66, longevity 100
- inputs: {"age_days": 3331, "days_push": 9, "days_rel": 146, "gap_med": 84, "n_releases_24m": 8}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5943, forks 676 (observed 2026-08-28T04:09:32.642180+00:00)

## What it is
Kotlin multiplatform serialization library consisting of a compiler plugin and runtime that generates serialization code for @Serializable classes without reflection. It supports JSON, Protobuf, CBOR, HOCON, and Properties formats across JVM, JS, and Native targets.

## Use cases
- encode kotlin data classes to
- parse  into kotlin objects
- serialize objects to protobuf in kotlin
- decode cbor payloads in a multiplatform app
- share serialization logic between jvm js and native kotlin
- convert kotlin objects to and from properties files

## When to choose
- you need reflectionless, high-performance serialization in Kotlin
- you want one serialization API shared across Kotlin Multiplatform targets
- you need JSON, Protobuf, CBOR, HOCON, or Properties support in Kotlin

## When to avoid
- your project is not in Kotlin
- you need exotic formats not covered by the built-in format libraries
- you rely on runtime reflection-based serialization of arbitrary classes

## Facets
- artifact type: library
- maturity: stable
- function: serialization
- domain: developer-tools, cross-platform, apis
- platform: jvm, windows, cross-platform
- tags: kotlin, multiplatform, compiler-plugin, cbor, protobuf, reflectionless, android, ios, nodejs, linux, macos

## Member repositories
- Kotlin/kotlinx.serialization (main) score 88

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:32.642180+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 2026-08-29T17:50:45.169675+00:00, confidence not recorded.
  - readme: https://github.com/Kotlin/kotlinx.serialization (fetched 2026-08-28T04:09:32.642180+00:00, sha 82b93f5e7ec0)
- Data as of 2026-08-30T08:39:29.467469+00:00.