Moderne Enhances Platform with C# Support for .NET Modernization

Moderne, a leader in AI-driven software engineering tools, has expanded its platform to include support for the C# programming language. This development introduces deterministic, large-scale code transformation capabilities to .NET codebases, allowing engineering teams and coding agents to automate processes for C# systems. Previously, these capabilities were available for Java, JavaScript/TypeScript, and Python. The enhancement is designed to minimize manual effort, enhance code quality, and expedite the modernization of .NET applications.

The timing of this C# support is crucial as .NET teams prepare for a major modernization phase. With the end-of-support for .NET 8 and .NET 9 scheduled for November 2026, there is an increasing need for automated tools that can manage extensive repository estates. Despite .NET's importance in industries such as financial services, healthcare, and government, teams have faced challenges in implementing safe, automated large-scale changes. The integration of C# into Moderne’s multi-language platform addresses this challenge, bringing .NET into the fold.

David Thoma, Head of Engineering at Billtrust, remarked, “Migrating hundreds of .NET repositories to .NET 10 would have required hundreds of engineering hours. With Moderne, we accomplished this at an unprecedented scale and speed, without sacrificing code quality or engineering discipline.”

C# is now part of the Moderne Lossless Semantic Tree (LST), a compiler-accurate structural model that enables deterministic transformations across repositories. The LST maintains code at a semantic level while preserving its formatting and structure, facilitating safe automated changes across numerous repositories without manual intervention. Recipes within the LST can analyze symbol usage, identify code quality issues, and perform coordinated transformations across entire systems. The shared data model of the LST ensures that foundational recipes like Change Method Name, Find Method Usages, and Change Type operate consistently across all supported languages.

Extensive Recipe Library

The initial release includes over 700 recipes categorized into two main groups. The code quality library features more than 420 recipes inspired by Roslynator, enabling enterprise-scale detection and remediation of style violations, correctness issues, and common anti-patterns across entire repository estates. Additionally, a migration library offers automated upgrade paths for .NET runtime transitions, covering versions from .NET Core 1.0 to .NET 10. Organizations can further customize this library with bespoke recipes written in C# or constructed from declarative YAML building blocks, applicable across all supported languages.

Jonathan Schneider, CEO and co-founder of Moderne, commented, “Coding agents are transforming software development and maintenance, and the most successful teams are those that combine agent speed with deterministic infrastructure. By adding C# to the Lossless Semantic Tree, .NET teams can now access the same governed, large-scale automation that our Java customers have relied on across thousands of repositories.”

ShiSh Shridhar, Global Director Retail & CPG Startups at Microsoft, noted, “Moderne's expansion into C# extends their automated, scalable approach to code modernization to one of the largest enterprise developer communities globally. We are pleased to continue supporting Moderne as they assist organizations in reducing the cost and complexity of maintaining and securing their .NET applications.”

Availability and Integration

C# recipes are distributed as NuGet packages and are immediately accessible through the Moderne Platform, utilizing existing workflows and governance controls. Engineering teams can perform code quality analysis, execute migration recipes, and manage dependencies, including NuGet package upgrades and .csproj dependency updates, using the established infrastructure for other supported languages.

Based in Miami, Moderne is an Agent Tools company that provides deterministic, governed infrastructure for AI coding agents operating across enterprise software systems. The company is dedicated to helping organizations scale AI-driven engineering with organization-wide intelligence and governed execution, continuously enhancing software quality while maximizing AI investment value. Moderne’s investors include Acrew Capital, Intel Capital, True Ventures, Mango Capital, Allstate Strategic Ventures, Morgan Stanley Ventures, Amex Ventures, and TIAA Ventures.