Fable 5 has been released 🎉

This is the result of almost 1 year and a half of work from the community and the maintainers.

Huge thank you to everyone involved. ❤️

#fsharp #fablecompiler

Funny timing — I just published a minimal RPC setup using the same Shared/Server/Client structure. The SAFE Stack really gave the ecosystem a great mental model.

🚀 Serde.FS alpha.9 — Deterministic RPC for F#

No reflection. No controllers.
Just compile‑time RPC clients + routing.

Includes:

• [<RpcApi>]
• ASP.NET RPC server
• Deterministic JSON backend
• Shared → Server → Client example

github.com/serde-fs/Ser...

#fsharp #rpc #aot #serde #dotnet

Releases · serde-fs/Serde.FS A compile‑time, reflection‑free serialization library for F#, including Serde.FS and Serde.FS.Json. - serde-fs/Serde.FS

Serde.FS.Json v1.0.0‑alpha.8 is out 🎉

• Full native codec
• System.Text.Json dependency removed!
• [<Serde.FS.EntryPoint>] for CLI apps
• Serde.FS.SystemTextJson backend is a WIP 🚧

github.com/serde-fs/Ser... #fsharp

I like using a record with a single field because it’s easier to unwrap the value, but single case DU is a common approach.

Not exactly. SourceDjinn came out of the internals I built for Serde.FS to get that "attribute-and-go" C# source generator experience.
Myriad definitely influenced the direction, though — you really can’t think about F# metaprogramming without thinking of Myriad!

The wait is over! Fable 5 Release Candidate is officially here.

After a year of hard work from the community, we're bringing you:
✨ .NET 10 & F# 10 support
🐍 A massive Python update (now powered by a Rust core & PyPI!)
🌐 Cleaner JS/TS Pojo bindings

fable.io/blog/2026/20...

#fsharp #fablecompiler

Serde.FS.Json is the first backend in the new Serde.FS ecosystem — fast, reflection‑free JSON for F#.

Powered by FSharp.SourceDjinn, a small engine for building F# source generators.

github.com/fs-djinn
#fsharp

As for ecosystem size, I think this may be the golden era for F# because the people using it do so because we love the language. We like making OSS projects for it, and it's now easier than ever for the community to create awesome stuff for the F# ecosystem -- which is exactly what is happening now.

I do all my work in F# and still get the warm glow. Simple functions as DSLs + small interim types allows me to design declarative workflow-specific pipelines that would be imperative in other langs. But as you move away from the code, perhaps it doesn't matter.

Release SqlHydra v3.5.0 · JordanMarr/SqlHydra SqlHydra.Query 3.5.0 New Feature: SQL Server Upsert (insertOrUpdateOnUnique) SqlHydra.Query now supports insert-or-update (upsert) for SQL Server via the new insertOrUpdateOnUnique custom operation...

SqlHydra v3.5 released with new query functionality for SQL Server. #fsharp

github.com/JordanMarr/S...

Well-articulated points.

Opus 4.6 is a savant junior coder. I just watched it try to add an `Errors` property to my response -- completely ignoring the fact that the function was wrapped in an `asyncResult` CE. 🤦‍♂️

Around 3 Years later but Migrondi v1 release is out!

#dotnet #fsharp #migrondi

Release v2.1.0 · JordanMarr/FSharp.SystemCommandLine ✨ New: First‑class dependency injection with Input.inject Input.inject now allows you to pass runtime dependencies (loggers, configuration, services, etc.) directly into your command actions as fir...

FSharp.SystemCommandLine v2.1 provides a more declarative way to inject services alongside CLI arguments and options.

github.com/JordanMarr/F... #fsharp

I've always said that "typing is not the bottleneck."
Thinking through the problem, use cases, edge cases and designing invariants is.

Release SqlHydra v3.3 + v3.4 · JordanMarr/SqlHydra An ergonomic release that modernizes how query contexts are created, improves left‑join projections, and introduces a more expressive join API. Fully backward‑compatible with 3.2, and forward-looki...

SqlHydra - v3.4 is out today. It is a rollup of the last two releases. Lots of nice, new features and some deprecated ones to help transition into an upcoming v4.0. #fsharp

github.com/JordanMarr/S...

GitHub - JordanMarr/fable-lit-fullstack-template: A SAFE-style template with Fable.Lit, Fable.Remoting and Giraffe A SAFE-style template with Fable.Lit, Fable.Remoting and Giraffe - JordanMarr/fable-lit-fullstack-template

Big update for the Fable + Lit ecosystem!

✨ Fable.Lit.Dsl
✨ Fable.Lit.Dsl.Shoelace
✨ Fullstack template update (.NET 10 + Fable 5)

#fsharp #webcomponents #lit
github.com/JordanMarr/f...

Releases · JordanMarr/Agent.NET A composable AI agent framework for .NET. Contribute to JordanMarr/Agent.NET development by creating an account on GitHub.

🚀 Agent.NET has evolved significantly since the alpha.1 announcement — alpha.2 and now alpha.3 bring proper MAF execution, symmetrical InProcess/Durable workflows, and a more cohesive workflow CE with ROP built in.

Full release history:
github.com/JordanMarr/A...

#fsharp #dotnet #aiagents

It's kind of funny that due to AI/LLMs these days another metric to rate #programming languages on has become "token efficiency".
On the bright side - some of the beloved languages like #Clojure, #Ruby, #FSharp and #OCaml fared pretty well due to their expressive and compact syntax.

GitHub - JordanMarr/Agent.NET: A composable AI agent framework for .NET. A composable AI agent framework for .NET. Contribute to JordanMarr/Agent.NET development by creating an account on GitHub.

github.com/JordanMarr/A...

A beautiful F# library for building AI agents on .NET:

• Quotation-based tool discovery
• Pipeline-style agent composition
• Computation expressions for workflows
• Railway-oriented error handling

F# deserves a place in the agent era — and this is my contribution.

#fsharp #dotnet

Release SqlHydra v3.2.0 · JordanMarr/SqlHydra SqlHydra.Query Built-in SQL Functions Use SQL functions directly in your queries with full type safety! Each database provider includes a SqlFn type with common functions. open SqlHydra.Query open ...

SqlHydra v3.2 big release today that builds on yesterday's release! Now includes DB-specific functions for all 5 supported DBs, custom functions, and adds .NET 10 support.
Samples included in the release notes.

github.com/JordanMarr/S... #fsharp

Release SqlHydra.Query v3.1.0 · JordanMarr/SqlHydra Support for SQL Functions You can now call custom functions supported by your database: open SqlHydra.Query // Create DB function stubs: let SUBSTRING (s: string, start: int, length: int) : string...

SqlHydra.Query v3.1.0 adds support for calling SQL functions!

github.com/JordanMarr/S... #fsharp

My FS Advent post for Dec 22, 2025. 🎄✨☕

Thanks to @sergeytihon.com for keeping the F# community buzzing along year after year!

jordanmarr.github.io/fsharp/cloud... #FsAdvent #fsharp

Sneak peek of new #fsharp side project...

Fable + Desktop 🤔

All day, every day!

I don’t notice much difference between my F# and C# project build times.
But I’ve heard some type provider libraries can slow it down though.

Great tips for getting real value out of FSI! I love the idea of creating bootstrap fsx scripts to preload modules. That alone will make FSI much more useful for non-trivial exploration.
And the MCP server obviously takes it to the next level as well.

Frogs ’n Flies was straight up my favorite Atari game back in the day!

If you hit the expert mode switch on the console, you could very precisely control your frog’s jump!

Bringing it back full circle in 2025 with the FP FrogInterpreter! ❤️🐸

Mark Seemann did a great talk years ago where he showed examples of some really gnarly method headers in C# to emphasize how type inference is almost a requirement for FP.
Would love to watch it again if I could find it.