riok/mapperly

Health v2 · maintenance only

Adoption not part of the score

4153 stars · 227 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Mapperly is a .NET source generator that automatically implements object-to-object mapping methods declared as partial methods, generating readable mapping code at build time. It uses no runtime reflection, making generated mappings fast, trimming-safe, and AOT-friendly.

Use cases

• generate object mapping code in .NET without runtime reflection
• map entities to DTOs in a layered application
• replace hand-written boilerplate mapping code in C#
• get compile-time warnings for unmapped properties
• create AOT and trimming-safe mappers for .NET
• map between enums and nested objects automatically
• project queryable objects for optimized ORM queries

When to choose

• you want fast, readable, debuggable mapping code generated at build time
• your app uses trimming or Native AOT and reflection-based mappers fail
• you want compile-time diagnostics for unmapped or ignored members
• you want zero runtime dependencies for mapping

When to avoid

• you need runtime-configurable or dynamic mappings decided at execution time
• you're not on .NET 5+ / C# 9+ with Roslyn 4.0+
• you prefer convention-based runtime mappers like AutoMapper with runtime configuration

Facets

library · maturity active

serialization build-tool developer-tools developer-tools backend web-development apis dotnet cross-platform source-generator roslyn object-mapping dto-mapping aot-friendly trimming-safe csharp no-reflection

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