What it does

openai-kotlin is a typed client for OpenAI’s API built on Kotlin coroutines and Ktor. It covers the full surface area: chat, images, embeddings, audio, fine-tuning, batch jobs, and the newer Assistants/Threads/Vector Stores beta. You bring a Ktor engine (OkHttp, CIO, etc.) and an API key; the library handles the rest.

The interesting bit

Multiplatform is the real pitch. The same dependency works in commonMain for JVM, JS, and WASM targets, with per-platform engine selection. That’s rarer than it should be in the LLM client space, where most libraries are JVM-only or Python-first afterthoughts.

Key highlights

• Coroutine-native: suspending functions throughout, no callback soup
• Multiplatform: commonMain dependency with per-target Ktor engines
• BOM support for Gradle version alignment (Maven users are out of luck here)
• ProGuard/R8 rules bundled in the JAR
• Live integration tests exist but are opt-in and billable; offline tests run by default

Caveats

• Unofficial and unaffiliated with OpenAI; API drift is your problem
• Gradle required for multiplatform; JVM-only Maven usage is possible but second-class
• Some features (Assistants, Vector Stores) are still in beta

Verdict

Kotlin developers building cross-platform or server-side LLM features should look here first. If you’re already in Python or don’t need multiplatform, this is just another API wrapper.