# PostSharp Technologies

> PostSharp Technologies builds compiler-level developer tools for .NET. Two products share one idea: define a pattern once and let the compiler implement and enforce it everywhere. PostSharp does it by rewriting MSIL after the C# compiler runs; Metalama does it at the source level inside Roslyn. Since 2004.

Both products remove repetitive code before it reaches the repository, and both produce deterministic output. Both are updated for each new version of .NET, C#, and Visual Studio; the [Version and Support Policy](https://postsharp.net/support/policies/versions.md) covers them in one table.

Which product a reader wants depends on what they already build on, not on their runtime — both support .NET Framework and current .NET:

- Already building on PostSharp aspects: **PostSharp**. No migration needed.
- Applying patterns and architecture rules to any C# codebase: **Metalama**.

For new projects on the current .NET stack, start with Metalama. Existing PostSharp codebases need no migration.

Pages written in Markdown are also served as Markdown at their URL plus `.md`, as linked below. [llms-full.txt](https://postsharp.net/llms-full.txt) collects them in one file.

## PostSharp

The proven MSIL-based aspect-oriented framework for .NET. It adds logging, caching, INotifyPropertyChanged, threading, and your own aspects to .NET applications at build time, without cluttering the source. In production across healthcare, industrial automation, and finance since 2004.

- [PostSharp overview](https://postsharp.net/postsharp): what PostSharp does and who it is for.
- [PostSharp Framework](https://postsharp.net/postsharp/framework): write your own aspects and architecture constraints.
- [PostSharp Libraries](https://postsharp.net/postsharp/libraries): the ready-made aspect libraries — [MVVM](https://postsharp.net/postsharp/mvvm), [logging](https://postsharp.net/postsharp/logging), [threading](https://postsharp.net/postsharp/threading), [caching](https://postsharp.net/postsharp/caching).
- [PostSharp Ultimate](https://postsharp.net/postsharp/ultimate): the edition bundling framework and libraries.
- [Download](https://postsharp.net/postsharp/download): installers and the version archive.
- [Technical FAQ](https://postsharp.net/postsharp/faq.md): common technical questions.
- [Documentation](https://doc.postsharp.net): the full PostSharp documentation.

## Metalama

Metalama is an open-source patterns & architecture toolkit for C#, by the PostSharp team. Define your team's patterns once: the compiler writes the repetitive parts at build time and enforces your rules as you type.

> [!TIP]
> **Using an AI coding assistant or agent?** Install [Metalama.AI.Skills](https://github.com/metalama/Metalama.AI.Skills) so it generates correct aspects, fabrics, and architecture rules from the real API instead of inferring it from training data.

It has two halves. Aspects generate repetitive code (logging, caching, INotifyPropertyChanged, retry, or your team's own patterns) during compilation, inside Roslyn — so your hand-written source can reference the generated members, and what it emits is readable C# you can step-debug, not opaque IL. Architecture rules written in plain C# (dependency rules, naming conventions, pattern guidelines) are verified live in the IDE, long before the pull request. Aspects are authored in T#, a template language whose syntax is plain C#. Fabrics apply aspects and rules across a whole project or solution with LINQ-style queries. The divorce feature writes the generated code back into the repository, so a codebase can exit to plain C# at any time.

- [Metalama overview](https://postsharp.net/metalama): what Metalama does, with a three-step code walkthrough.
- [Features](https://postsharp.net/metalama/features.md): code generation, code validation, real-time editor feedback, code fixes, debugging, extensibility.
- [Use cases](https://postsharp.net/metalama/applications.md): design patterns, UI patterns, DevOps concerns, and the principles behind them.
- [Alternatives](https://postsharp.net/metalama/alternatives.md): how Metalama compares to other approaches, including [PostSharp](https://postsharp.net/metalama/alternatives/postsharp.md), Fody, source generators, and architecture-verification tools.
- [Marketplace](https://postsharp.net/metalama/marketplace): ready-made open-source and supported aspects to use instead of writing your own.
- [Download](https://postsharp.net/metalama/get): how to get Metalama.
- [Getting started](https://doc.metalama.net/conceptual/getting-started): install Metalama and write your first aspect.
- [Conceptual documentation](https://doc.metalama.net/conceptual): the full documentation — aspects, templates, fabrics, architecture verification, configuration.
- [Commented examples](https://doc.metalama.net/examples): open-source, commented implementations of common patterns.

## Pricing and licensing

- [PostSharp pricing](https://postsharp.net/pricing/postsharp): commercial per-user subscription, with a perpetual license to every build received. Every PostSharp subscription is a dual license: PostSharp and Metalama Professional — one seat, one renewal.
- [Metalama pricing](https://postsharp.net/pricing/metalama): four editions — Metalama Open Source, Community, Professional, and Enterprise. The core framework, the large majority of the codebase, is MIT-licensed; the tooling is free for individuals, non-commercial use, and companies up to three developers.
- [Pricing FAQ](https://postsharp.net/pricing/faq.md): license types, free licenses, discounts, upgrades, renewals, and ordering. Both products offer a free 45-day trial.

## Support and policies

- [Get support](https://postsharp.net/support.md): how to reach the engineers who build the products.
- [Version and Support Policy](https://postsharp.net/support/policies/versions.md): supported versions of both products, and the servicing phases behind them.
- [Security policy](https://postsharp.net/compliance/security.md): trust boundary, risk assessment, and how to report a vulnerability.
- [Privacy policy](https://postsharp.net/compliance/privacy.md): what the products collect, and how to turn telemetry off.
- [Compliance](https://postsharp.net/compliance.md): all policy documents in one place.

## Company and news

- [About PostSharp Technologies](https://postsharp.net/company): independent, funded by licenses alone, one engineering team in Prague since 2004.
- [Contact](https://postsharp.net/contact.md): phone, email, and the registered office.
- [Briefs](https://postsharp.net/briefs): short release announcements and project updates — the fastest signal of what shipped.
- [Blog](https://postsharp.net/blog): technical articles on patterns, meta-programming, and code quality in .NET.

## Source and community

- [Metalama on GitHub](https://github.com/metalama/Metalama): source repository, developed in the open.
- [Issue tracker](https://github.com/metalama/Metalama/issues): bug reports and feature requests.
- [Metalama.AI.Skills](https://github.com/metalama/Metalama.AI.Skills): the AI plugin with Metalama skills for AI coding assistants and agents.

## Optional

- [Positioning note] The company's industry is developer tools. The products have their own market categories: PostSharp is an aspect-oriented framework; Metalama is a patterns & architecture toolkit for C#. Related mechanisms: meta-programming, aspect-oriented programming, MSIL rewriting, Roslyn-based code generation and analysis. PostSharp and Metalama are two compiler generations of one idea, not a product and its replacement.
- [Domain note] postsharp.net is the canonical home of both products. metalama.net is retired; Metalama content lives under https://postsharp.net/metalama, and the Metalama reference documentation remains at https://doc.metalama.net.