# MessagePack-CSharp/MessagePack-CSharp

Extremely Fast MessagePack Serializer for C#(.NET, .NET Core, Unity, Xamarin). / msgpack.org[C#]

Repository: https://github.com/MessagePack-CSharp/MessagePack-CSharp
Canonical: https://ross.abutalabs.com/products/messagepack-csharp
Language: C#
License: NOASSERTION
License Family: other
Topics: messagepack, unity, serialization, xamarin, c-sharp, msgpack, lz4, serializer
Last push: 2026-08-20T05:39:04+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 87, longevity 100
- inputs: {"age_days": 3489, "days_push": 13, "days_rel": 85, "gap_med": 6.5, "n_releases_24m": 17}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6774, forks 772 (observed 2026-08-28T04:09:48.455477+00:00)

## What it is
An extremely fast MessagePack binary serializer for C# targeting .NET, .NET Core, Unity, and Xamarin. It includes built-in LZ4 compression and outperforms other C# serializers for performance-critical applications.

## Use cases
- serialize game state efficiently in Unity
- fast binary serialization for microservices
- compress network payloads with LZ4
- replace JSON with a compact binary format in C#
- serialize objects for distributed computing or data caches
- serialize data in Xamarin mobile apps

## When to choose
- you need the fastest C# serializer with compact binary output
- you're building games or real-time systems in Unity where serialization speed matters
- you want built-in LZ4 compression without extra dependencies
- you need cross-platform .NET serialization including Unity and Xamarin

## When to avoid
- you need human-readable serialization like JSON
- your project is not on the .NET/Unity ecosystem
- you need schema evolution features of protobuf with cross-language tooling
- you only serialize small payloads where speed is irrelevant

## Facets
- artifact type: library
- maturity: stable
- function: serialization, compression
- domain: developer-tools, microservices, performance
- platform: cross-platform, game-engine, dotnet
- tags: messagepack, c-sharp, lz4, binary-serialization, unity, xamarin, game-development, mobile

## Member repositories
- MessagePack-CSharp/MessagePack-CSharp (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:48.455477+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 2026-08-29T17:42:24.106686+00:00, confidence not recorded.
  - readme: https://github.com/MessagePack-CSharp/MessagePack-CSharp (fetched 2026-08-28T04:09:48.455477+00:00, sha f159676ed96e)
- Data as of 2026-08-30T08:39:29.467469+00:00.