Axial
Repository F# setup
open System
open System.IO
open System.Threading
open System.Threading.Tasks
open Axial
open Axial.Layers
open Axial.Console
open Axial.FileSystem
open Axial.Hosting
open Axial.Hosting.Browser
open Axial.Hosting.Node
open Axial.PlatformService
open Axial.State
open Axial.Telemetry
open Axial.Telemetry.JavaScript

Effect-TS Comparison

Axial and Effect-TS both model typed effects. Axial runs on .NET and through Fable, so an F# application can use the same Flow model on server, Node, and browser targets without adopting Effect-TS for JavaScript deployment.

Shared model

Both libraries provide concepts for:

  • typed success and expected-error channels
  • explicit services and dependency provisioning
  • cold, compositional workflows
  • cancellation and structured concurrency
  • resource scopes and deterministic cleanup
  • retries, schedules, and timeouts
  • streams
  • runtime observability

The names and exact semantics differ. This list describes the areas of overlap, not API compatibility.

Why use Axial from F#

Axial keeps the workflow and domain model in F#:

  • flow { } uses F# computation-expression syntax.
  • Flow<'env, 'error, 'value> exposes dependencies, expected errors, and success in an F# type.
  • Result and Async bind directly on .NET and Fable; .NET targets bind ColdTask for cold, cancellation-aware task factories. Raw Task and ValueTask values require explicit started-work adapters.
  • On Fable, Async is the Flow-facing bridge for JavaScript asynchronous work. Promise-returning APIs can be adapted to Async and then bound in flow { }; application code does not need Effect-TS merely to await a Promise.
  • Environment records and layers use ordinary F# values rather than a JavaScript-facing context boundary.
  • FlowStream uses the same environment, error, cancellation, and runtime model on .NET and Fable.
  • Node and browser hosting packages connect Flow interruption to platform lifecycle signals.
  • Fable telemetry integrates with the JavaScript observability platform without changing the application workflow.

Shared F# code can retain Axial's typed effects, concurrency, streams, and observability across the generated-JavaScript boundary without translating workflows into Effect-TS.

The concrete Promise adapter is Fable's Async.AwaitPromise; because flow { } binds Async directly, an adapted Promise is one let! away:

Fragment
open Fable.Core

let awaitPromise (promise: JS.Promise<'T>) : Async<'T> =
    Async.AwaitPromise promise

let readRemote : Flow<unit, string, 'T> =
    flow {
        let! value = awaitPromise (loadRemote ())  // loadRemote returns JS.Promise<'T>
        return value
    }

When Effect-TS is still the natural boundary

Use Effect-TS when the workflow is owned by TypeScript or must compose directly with an existing Effect-TS application and its services. Calling that application from generated F# may be a legitimate integration boundary. The JavaScript deployment target alone does not require Effect-TS as the runtime for F# code.

Use Axial when F# owns the application workflow and the code needs to run on .NET, Node, the browser, or a combination of those targets. The same Flow API then remains the application model rather than an adapter on the way to a second effect system.

Compare concrete requirements

Compare the application's requirements:

  • which language owns orchestration and service definitions
  • whether workflows are shared between .NET and Fable
  • which platform APIs require adapters
  • which concurrency and stream operators the application actually uses
  • which telemetry backend and hosting lifecycle own execution

For an F#-owned application, use Axial on every target its packages support: Axial, Axial.Layers, and the operational packages run on .NET, Node, and browser, while Axial.Hosting is .NET-only and the Node/browser host adapters are JavaScript-only. See Packages and platforms for the matrix before choosing a target. Introduce an Effect-TS boundary only when the application must participate in TypeScript code that already uses Effect-TS.