CloudEvents Kotlin SDK

July 10, 2026 · View on GitHub

A CNCF project — part of the CloudEvents ecosystem.

What It Is

A Kotlin Multiplatform SDK for CloudEvents, the CNCF-governed specification for describing event data in a common way. The SDK provides a type-safe, idiomatic Kotlin API for composing, validating, encoding, and decoding CloudEvents across JVM, JavaScript, WebAssembly, and native platforms.

The :core module is a pure-Kotlin, stdlib-only library with no JVM-specific dependencies — it compiles on every supported Kotlin Multiplatform target from a single shared source set.

Version Support Policy

This SDK supports CloudEvents v1.0 (latest spec text 1.0.2, honoring 1.0.1 clarifications) and v0.3 per the CloudEvents SDK support policy special case.

The CloudEvents SDK support policy requires each SDK to support the latest major spec version (currently v1.0) and, while v1.0 is the latest, also v0.3. Within a major version only the latest minor text is tracked — there is no runtime toggle between v1.0.1 and v1.0.2; both carry the "1.0" specversion value.

For the authoritative policy definition, see: cloudevents/spec — SDK Requirements

Modules

Module	Status	Description
`:core`	Active	CloudEvent data model, type system, attribute validation, and Message-SPI interfaces. Stdlib-only, no third-party runtime dependencies.
Format modules (JSON, Avro, Protobuf)	Planned	Encode and decode CloudEvents in each event format.
Protocol binding modules (HTTP, Kafka, AMQP, ...)	Planned	Transport-specific binary and structured content modes.

KMP Target Matrix

Target	Platform	CI Status
`jvm`	Any (JDK 21+)	Tested
`js` (Node)	Node.js >= 18	Tested
`wasmJs` (Node)	Node.js >= 18	Tested
`linuxX64`	Linux x86-64	Tested
`linuxArm64`	Linux ARM64	Planned CI
`macosX64`	macOS x86-64	Planned CI
`macosArm64`	macOS Apple Silicon	Planned CI
`iosArm64`	iOS device (ARM64)	Planned CI
`iosX64`	iOS Simulator (x86-64)	Planned CI
`iosSimulatorArm64`	iOS Simulator (Apple Silicon)	Planned CI
`mingwX64`	Windows x86-64	Planned CI

"Tested" targets run on ubuntu-latest in CI on every PR. "Planned CI" targets compile on any host but require a macOS (Apple targets) or Windows (mingwX64) runner for test execution; these are added in a future CI expansion.

Installation

Note: cloudevents-kotlin-core is not yet published to Maven Central. Until a release is available, add it as a project dependency from source.

The artifact coordinates when published will be:

// build.gradle.kts
dependencies {
    // cloudevents-kotlin-core is not yet published; add as a project dependency for now
    implementation("io.cloudevents:cloudevents-kotlin-core:<version>")
}

Group: io.cloudevents Artifact: cloudevents-kotlin-core

Contributing

Contributions are welcome. Before submitting a pull request, please read CONTRIBUTING.md for the full workflow — covering branching, DCO sign-off, Conventional Commits, build and test instructions, and the code review process.

License

Apache License 2.0 — see LICENSE.