F# Weekly #21, 2026 – Scriptorium, Elmish Land 2.0 Preview & RProvider 3.0

Welcome to F# Weekly,

A roundup of F# content from this past week:

News

• Scriptorium – A family of focused F# libraries for building and testing F#/Fable applications.
• Announcing Elmish Land 2.0 Preview
• The Impact of Automated Repository Maintenance Assistance

A new test framework joining the F# ecosystem: Scriptorium.It is designed from the ground up as a cross-target testing framework, seamlessly supporting both F# .NET and Fable compilation targets (JavaScript only at the time of writing)fable-hub.github.io/Scriptorium/#fsharp #fablecompiler

— Maxime (@mangelmaxime.bsky.social) 2026-05-18T13:45:57.590Z

Microsoft News

• Improving C# Memory Safety
• Announcing Agent Governance Toolkit MCP Extensions for .NET
• Your dev loop is full of tribal knowledge | Aspire Blog
• NuGet Package Pruning: Cleaner Dependencies and Actionable Vulnerability Reports
• Securing Azure apps with Aspire enterprise networking | Aspire Blog
• Plan Before You Build: Introducing the Plan agent in Visual Studio – Visual Studio Blog
• Visual Studio Code 1.121

Videos

• .NET Data Community Standup: 8 Real-World Query Anti‑Patterns (and How to Fix Them)
• .NET AI Community Standup: .NET + AI at Build 2026: What’s Coming Next?
• On .NET Live: How Coding Standards Supercharge .NET Quality & Performance

Blogs

• Drawing mountains: setting up Bolero · Mathias Brandewinder
• Event Sourcing — Trade-offs of Event Versioning and Migrating Approaches – Urs Enzler

Oh nice, Scott Wlaschin's Domain Modeling Made Functional is in the Functional Programming Humble Bundle! #fsharp https://www.humblebundle.com/books/ultimate-functional-programming-pragmatic-programmers-books

— Loïc Denuzière (@tarmil.mastodon.tarmil.fr.ap.brid.gy) 2026-05-19T09:49:41.000Z

Highlighted projects

• DataficationSDK/Verso — Extensible interactive notebook platform for .NET. Every built-in feature, from the C# kernel to the dashboard layout, is an extension built on the same public interfaces available to third-party authors. Runs in VS Code and the browser.
• bartul/imperium — Strategy board game engine for Imperial (Mac Gerdts), exploring F# DDD and CQRS patterns
• fsprojects/FSharp.Control.R3 — Extensions and wrappers for using R3 reactive programming with F#
• ScottArbeit/Grace — Grace Version Control System built in F# with Orleans and cloud-native design

With the latest Notepad++ there is a Treesitter v1.1 plugin that supports #fsharp and many other languages

— Tuomas Hietanen (@thoriumi.bsky.social) 2026-05-20T21:10:39.213Z

New Releases

• FSharp.Compiler.Service 43.12.204
• WebSharper 10.1.5.674
• Feliz 3.3.3
• Feliz.UseElmish 5.0.0
• Akka.FSharp 1.5.68
• Akka.Persistence.FSharp 1.5.68
• FSharp.Formatting 22.0.1
• RProvider 3.0.0
• SageFs 0.6.273
• FSharp.Idioms 1.5.10
• FParsec-Pipes 1.3.0
• TickSpec 2.0.5
• Prime 11.5.1
• FSharp.HotChocolate 1.0.2
• DeviantArtFs 12.0.0
• Fesh 0.32.2
• linq2db.FSharp 6.3.0
• Farse 0.12.2
• XParsec 1.0.0
• FsLangMcp 0.9.2
• Hedgehog.Stateful 1.1.1

That’s all for now. Have a great week.

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