.NEXT

.NEXT (dotNext) is a set of powerful libraries designed for high-performance scenarios when your application expects near zero memory allocation and high flexibility. It is aimed to high-load microservices, database engines, actors, and various types of distributed applications. The feature list includes a rich set of efficient tools with low overhead:

• Buffer manipulations
• String building
• Monadic types
• Advanced GC notifications
• Low-level API to work with memory: alignment detection, type-safe unmanaged allocators, Span<T> manipulations
• Base64 streaming encoder/decoder
• Async-friendly SIEVE cache
• Async locks
• Extended LINQ Expression Trees and dynamic code generation tools with async lambdas for metaprogramming
• Raft Consensus Algorithm with extensions such as the failure detection
• Fast general-purpose Write Ahead Log
• TCP multiplexing protocol
• HyParView protocol implementation

All these things are implemented in 100% managed code on top of existing .NET API.

Quick Links

• Features
• API documentation
• Benchmarks
• NuGet Packages

AI Agent Skills

.NEXT provides Agent Skills that teach AI coding agents (Claude Code, Codex, GitHub Copilot, Cursor and others) how to use the libraries efficiently:

• dotnext-core - Optional and Result monads, timestamps, type maps, console app lifetime, etc.
• dotnext-threading - asynchronous programming, async locks, etc.
• dotnext-concurrency - concurrent data structures
• dotnext-memory - allocation-free memory routines, buffer writers, memory pooling

To install:

Claude Code:

/plugin marketplace add dotnet/dotNext
/plugin install dotnext-skills@dotnext

Codex:

codex plugin marketplace add dotnet/dotNext
codex plugin add dotnext-skills@dotnext

Any agent supporting Agent Skills, via skills CLI:

npx skills add dotnet/dotNext

Alternatively, copy the skill folders from ai/plugins/dotnext-skills/skills to the skills directory of your agent, e.g. .claude/skills/ for Claude Code, or .agents/skills/ for Codex and GitHub Copilot.

What's new

Release Date: 10-06-2026

A set of skills for AI agents has been released: skills explain how to use .NEXT libraries in a new project or migration scenarios.

DotNext 6.9.0

• Fixed stack allocation threshold in SpanOwner
• String interpolation helpers are available as static extension methods for String class
• Added SkipNulls extension method overload for nullable value types
• Added Flatten extension method to skip empty values of Optional monadic type in enumerations
• Introduced Infer extension method to force automatic delegate type inference in C#
• Added ReferenceCounted<T> class which implements concurrent reference counting for a generic resource

DotNext.Metaprogramming 6.9.0

• Updated dependencies

DotNext.Unsafe 6.9.0

• Updated dependencies

DotNext.Threading 6.9.0

• Fixed XML docs for AsyncStateTracker class
• Added collection builder support to AsyncEventHub.EventGroup inner type
• Fixed 302

DotNext.IO 6.9.0

• Removed null check in hot execution paths for FileReader and FileWriter types
• Default buffer size for FileReader and FileWriter is equal to the system page size

DotNext.Net.Cluster 6.9.0

• Fixed 301

DotNext.AspNetCore.Cluster 6.9.0

• Updated dependencies

DotNext.MaintenanceServices 1.9.0

• Updated dependencies

Changelog for previous versions located here.

Release & Support Policy

The libraries are versioned according to Semantic Versioning 2.0.

Version	.NET compatibility	Support Level
0.x	.NET Standard 2.0	❌
1.x	.NET Standard 2.0	❌
2.x	.NET Standard 2.1	❌
3.x	.NET Standard 2.1, .NET 5	❌
4.x	.NET 6	❌
5.x	.NET 8	✅
6.x	.NET 10	✔️

❌ - unsupported, ✅ - bug and security fixes only, ✔️ - active development

Development Process

Philosophy of development process:

1. All libraries in .NEXT family are available for various .NET form factors: Mono, WASM, NativeAOT
2. Minimal set of dependencies
3. Provide high-quality documentation
4. Stay cross-platform
5. Provide benchmarks

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the .NET Foundation Code of Conduct. For more information see the Code of Conduct FAQ or contact conduct@dotnetfoundation.org with any additional questions or comments.