Reified
Repository F# setup
open Reified
open Reified.Refinements
open Reified.Result
open Reified.Schema.Json
Reified

F# libraries for .NET and Fable JavaScript

Encode each invariant once. Enforce it across the project.

Declare a rule once — on a value, a field, or a whole model — and the checking, the diagnostics, the JSON codec, the contract document, and the test data are all read from that one declaration.

type Signup = { Email: string; Age: int; Newsletter: bool }

let signupSchema =
    schema<Signup> {
        field _.Email { constraints [ present; email ] }
        field _.Age { constrain (atLeast 13) }
        field _.Newsletter
        construct (fun email age newsletter ->
            { Email = email; Age = age; Newsletter = newsletter })
    }

Schema.parse signupSchema input
// age: Expected a value at least 13, but was 11.
// email: Expected an email address, but was ada.
// newsletter: This value was omitted.

Json.serialize (Json.compile signupSchema) signup
// {"email":"ada@example.org","age":36,"newsletter":true}

Every failure message, the JSON codec, the JSON Schema, and the generated test data come from that one declaration. Nothing above is written twice.

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Route by symptom

Problem Goes to
Validation boilerplate is everywhere, and invalid values still get through Constraints
The same rule is repeated in a parser, a form, and a test Schema
Decoding and validation are separate steps that drift apart JSON Codecs
Constructing structured test data by hand is slow and repetitive Data
You want one small library, not a framework Packages and platforms

Every package is independently installable and runs on .NET and on Fable JavaScript — take one capability or the whole set. Packages and platforms →

Getting started GitHub