Nostr4j

A high-performance Nostr library for the JVM, designed to be high throughput, memory efficient, and transpilable to JavaScript.

The library is designed to be flexible and extensible. It provides some key abstractions to make development easier, but does not enforce any specific architecture or design, while also exposing the low-leve building blocks on top of which the abstractions are built.

The library has built-in support for:

• nips: 01, 04, 05, 07, 09, 24, 39, 40, 44, 46, 47, 49, 50
• managed nwc wallets
• wallet abstraction
• signer abstraction
• configurable ack policies (with some default implementations such as: quorum, all, any)
• automatic relays lifecycle management
• webrtc over nostr
• blossom

and more...

Usage

Include the library:

repositories {
    mavenCentral()
    // Uncomment this if you want to use a -SNAPSHOT version
    //maven { 
    //    url = uri("https://central.sonatype.com/repository/maven-snapshots")
    //}
}

dependencies {
    implementation 'org.ngengine:nostr4j:<version>'
}

Tip

As <version> use one of the versions listed in the releases page or 0.0.0-SNAPSHOT for the latest snapshot.

Add the right nge-platform for your target platform from maven central. For example, for desktop:

dependencies {
    // ...
    implementation 'org.ngengine:nge-platform-jvm:<version>' // note: this requires java 21+
    // ...
}

Note

This library can be included in projects targeting java 11 or higher, but it requires java 21+ if you use nge-platform-jvm and to run tests (./gradlew test). This is due to nge-platform-jvm using some java 21+ features, such as virtual threads, async http client, etc.. to improve performance.