OpenRewrite vs Roslynator

OpenRewrite is an open-source ecosystem for automated code refactoring, aimed at updating code and reducing technical debt. It represents code as Lossless Semantic Trees, applies transformations, and prints the result back into source code for review. Its recipes cover framework migrations, security fixes, and style consistency, and can be written in YAML, Refaster templates, or Java. Maven and Gradle plugins run recipes locally as part of builds, one repository at a time. The Maven plugin offers a dry run that reports potential changes and writes diff files; recipes run only when explicitly activated by name. Documented support includes Java, Kotlin, and Groovy, plus formats such as HCL, JSON, Properties, Protobuf, TOML, XML, and YAML. Framework coverage includes Spring, Quarkus, and Micronaut. The recipe index lists 4,183 recipes across modules. Core and language libraries use Apache License 2.0, but some recipes have other licensing terms. Core is free; some artifacts require authenticated repository access, and some recipes require a Moderne subscription.

Roslynator is a set of code analysis tools for C# development environments built on Roslyn. Its IDE extensions offer refactorings and fixes for compiler diagnostics, while analyzers are distributed separately through NuGet packages. Listed editor extensions cover Visual Studio 2026 and 2022, VS Code, and Open VSX. The VS Code extension requires legacy OmniSharp with `dotnet.server.useOmnisharp` set to true and does not work with C# Dev Kit. A command-line tool can be installed with `dotnet tool install -g roslynator.dotnet.cli`; the CLI is also integrated into MegaLinter for CI. EditorConfig settings can configure analyzers, refactorings, and compiler diagnostic fixes, and a testing framework supports unit tests for those tools. The .NET client libraries extend the Roslyn API but do not include analyzers or refactorings. The repository is licensed under Apache License 2.0. Its security policy supports version 5.x, CLI 0.x, and the Visual Studio 2026 and VS Code extensions; versions below 5.0 and Visual Studio 2022 extensions are out of support.