# MapsterMapper/Mapster

A fast, fun and stimulating object to object Mapper

Repository: https://github.com/MapsterMapper/Mapster
Canonical: https://ross.abutalabs.com/products/mapster
Homepage: http://mapstermapper.github.io/Mapster/
Language: C#
License: MIT
License Family: permissive
Topics: mapper, c-sharp, fast, mapping, codegenerator
Last push: 2026-08-25T11:11:54+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 98, longevity 100
- inputs: {"age_days": 4478, "days_push": 8, "days_rel": 14, "gap_med": 11.0, "n_releases_24m": 9}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5163, forks 407 (observed 2026-08-28T04:09:11.524049+00:00)

## What it is
Mapster is a fast, convention-based object-to-object mapping library for .NET/C#. It supports mapping to new or existing objects, queryable projection, dependency injection, and code generation of DTOs and mapper classes.

## Use cases
- map entities to DTOs in a .NET API
- replace AutoMapper with a faster mapper
- project EF Core queryables directly to DTO types
- generate DTO classes and mapper code at build time
- map one object onto an existing instance

## When to choose
- you need high-performance object mapping in C#
- you want compile-time code generation for mappers
- you use EF Core and want ProjectTo-style projections

## When to avoid
- your project is not on .NET/C#
- you need complex, highly customized mapping logic better served by hand-written code

## Facets
- artifact type: library
- maturity: active
- function: serialization, developer-tools
- domain: developer-tools, backend, apis
- platform: dotnet, cross-platform
- tags: object-mapping, dto, csharp, code-generation, automapper-alternative

## Member repositories
- MapsterMapper/Mapster (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:11.524049+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 2026-08-29T18:01:53.305538+00:00, confidence not recorded.
  - readme: https://github.com/MapsterMapper/Mapster (fetched 2026-08-28T04:09:11.524049+00:00, sha 0eb6f35887e8)
  - homepage: http://mapstermapper.github.io/Mapster/ (fetched 2026-08-29T08:55:55.709634+00:00, sha 8c8423efb693)
- Data as of 2026-08-30T08:39:29.467469+00:00.