Why is Kotlin SDK always left behind?

[realreus319]

I have to ask — why are Python and JavaScript SDKs always prioritized, while the Kotlin SDK lags behind by months?

It’s already August, and we still can’t use streamable server features in the Kotlin SDK. This is extremely frustrating for developers who want to build serious AI infrastructure using Kotlin — a fully capable, modern language that's widely used on the JVM and in multiplatform development.

As a passionate Kotlin supporter, I feel left out. We’ve been waiting since March for basic MCP 0.10+ features.

Please be fair. Please provide timelines. Please support Kotlin properly.

[shiqicao]

more frequent release, currently it seems very 2~3 months

[StefMa]

more frequent release, currently it seems very 2~3 months

You could vote for snapshot releases at least #116 👀

Each merge to main would end up in a new release and we would be a bit closer to the edge.
Not saying that fix the majority of "kotlin sdk is left behind", but at least a bit, I guess... 🤷‍♂️

[devcrocod]

You are right, the kotlin-sdk is currently lagging behind in implementing the latest versions of the specification. We’re actively working on aligning the kotlin-sdk with the most recent version:

• 2025-03-26
• 2025-06-18

Regarding releases, we’re also in the process of defining a transparent and convenient release strategy. As @StefMa mentioned, we’re likely to introduce snapshot/dev releases either triggered by changes to the main branch or on a time-based schedule, such as weekly

The current version is 0.6.0. After some upcoming server changes #198 and the addition of integration tests #216, we plan to release version 0.7.0. Following that, we aim to establish the new release cycle

[pambrose]

Guys, I am eternally thankful for your efforts with Kotlin. However, I am gravely concerned about the priority being assigned to the MCP server repo. There is a land-grab underway for AI-relevance among the languages and JB's inability/unwillingness to keep up with the MCP versions is really damaging to anyone trying to promote Kotlin in the AI world. Please treat this with the urgency it deserves. If you are comfortable being multiple release behind, do not even bother with it. IMHO, there is no way in hell the java and python impls should be way ahead of the kotlin implementation.

[Ndemco]

I was planning to use the Kotlin MCP SDK for our MCP servers at work, but ended up switching to the Go SDK — it’s just more advanced right now and already supports Streamable HTTP. Kind of disappointed in JetBrains for falling behind here. I’ve been 100% Kotlin for two years, and this is the first time I’ve reached for another language.

[bczhaoa]

Brothers, when will the Kotlin SDK support Streamable HTTP?

[kpavlov]

Brothers, when will the Kotlin SDK support Streamable HTTP?
@bczhaoa, we are working on it, it's high priority task

[devcrocod]

Closing this issue as resolved

Since this was opened:

• Streamable HTTP is fully implemented for both client and server as of 0.8.0
• the sdk now passes the full MCP conformance test suite - Kotlin SDK - Tier 3 Assessment modelcontextprotocol#2512

If anything is still missing, feel free to open a specific issue