A modern language for .NET

Write expressive programs.
Keep the whole platform.

Raven brings typed, expression-oriented programming, algebraic modeling, and familiar object-oriented design to the .NET ecosystem.

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Raven is under active development. Evolving areas are marked in the documentation.

modeling.rvn

record Shipment(Id: int, Weight: decimal)

union QuoteResult {
    case Quoted(amount: decimal)
    case Rejected(reason: string)
}

func Quote(shipment: Shipment) → QuoteResult {
    if shipment.Weight <= 0 {
        return .Rejected("Weight must be positive")
    }

    return .Quoted(12.50m + shipment.Weight * 1.75m)
}

expressions.rvn

func Describe(result: QuoteResult) → string {
    return match result {
        .Quoted(let amount) when amount > 100m
            => "Large quote: $amount"
        .Quoted(let amount)
            => "Quote: $amount"
        .Rejected(let reason)
            => "Cannot quote: $reason"
    }
}

let message = Describe(Quote(Shipment(42, 3.5m)))

dotnet.rvn

import System.Console.*
import System.Text.Json.JsonSerializer

record Package(Name: string, Version: string)

let package = Package(
    Name: "Raven.Core",
    Version: "0.1.0"
)

let json = JsonSerializer.Serialize(package)
WriteLine(json)

One language, complementary tools

Use the right shape for the problem.

Build value-oriented models with records and unions, compose behavior with functions and expressions, and reach for classes when identity or open polymorphism matters—all with direct access to .NET libraries.

Tour Raven in 60 seconds See the language's core ideas in one small program. Learn Choose your path Start from .NET experience or from programming fundamentals. Reference Explore the language Find precise syntax, semantics, and language guidance.

Write expressive programs.Keep the whole platform.

Use the right shape for the problem.

Write expressive programs.
Keep the whole platform.