A fully multiplatform, Ktor-kased NATS client in pure Kotlin

NATS.kt is a high-performance NATS client built specifically for Kotlin Multiplatform. Powered by Ktor's networking stack, it brings NATS messaging to every platform Kotlin supports - including servers, mobile apps, browsers and native applications.

• Universal Platform Support: Deploy your NATS-powered applications anywhere Kotlin runs
• Transport Flexibility: TCP and WebSocket transports supported
• Coroutines: Coroutine-based API for idiomatic reactive programming
• DSL-style usage: Clean, idiomatic Kotlin API with DSL configuration
• Built on Ktor: Leverage Ktor's stability for networking capabilities and performance

Minimum JVM: 17

Minimum Kotlin: 2.1

Gradle:

commonMain.dependencies {
	implementation("io.github.n-hass:natskt-core:0.7.0")
	// and if you want jetstream:
	implementation("io.github.n-hass:natskt-jetstream:0.7.0")
}

import io.natskt.NatsClient

// Simple connection
val client = NatsClient("nats://localhost:4222")
client.connect()

// Advanced configuration
val client = NatsClient {
    server = "nats://localhost:4222"
    transport = TcpTransport
}

val client = NatsClient {
    server = "ws://localhost:4222"
    transport = WebSocketTransport.Factory(CIO)
}

// Subscribe to messages
val subscription = client.subscribe("orders.new")
subscription.messages.collect { message ->
    println("Received: ${message.data}")
}

NATS.kt is under active development.

Legend: ✅ Complete | 🟠 Partially Complete | 🚧 In Progress | ❌ Planned

Check out our examples directory for comprehensive usage examples:

• Basic Subscribe - Simple message subscription
• Requests - Making requests with core NATS
• JetStream - Using the JetStream management API and binding to a consumer
• Custom Credentials - Providing custom authentication credentials for use with auth-callout

More coming soon!

Please do not rely on the NKEY/Creds authentication features included in this client in a production environment. Although functionally correct, some cryptographic operations have not been formally verified and may have vulnerabilities.

The NKEY implementation uses an Ed25519 algorithm implementation from an un-attested library. This is used to sign authentication requests by the server on connect.

I plan to move the NKEY implementation to use cryptography-kotlin, a multiplatform binding to various other platform-native attested libraries, like JCA, OpenSSL and WebCrypto. This is waiting on the features being developed in that library upstream.

The rest of the secure operations, including secure-random and TLS for TCP and WebSocket transports, use implementations which delegate to platform-native libraries and should not pose a notable security risk.

NATS.kt is released under the Apache 2.0 License.

• Dimensional-Fun NATS.kt - For some foundational code and inspiration
• Ktor - The networking foundation

Ready to build the next generation of distributed Multiplatform applications? Star ⭐ this repo and join our community!