Kotlin Backend Developer (Kocelot Team, Platform)

At JetBrains, code is our passion. Since 2000, we’ve been building the most effective developer tools in the world – tools that automate routine tasks and empower developers to focus on creativity, exploration, and problem-solving.

We’re looking for a Kotlin Backend Developer to join the Kocelot team and help us build the foundation of a new platform for developing domain-specific languages (DSLs).

Kocelot is an experimental project aimed at rethinking how DSLs are designed, analyzed, and embedded into modern applications. The platform combines language definition tools, reactive data processing infrastructure, and a new take on projectional editing – all designed to work seamlessly in web environments. Our goal is to make it easier for teams to build expressive, embeddable languages tailored to their domains.

You’ll be working on the core backend layer: a system that manages structured user data, tracks changes over time, and powers live, incremental processing of language semantics.

As part of our team, you will: 

• Design and develop scalable backend services for DSL semantic analysis and execution.
• Work on versioned, structured data storage for reactive data processing.
• Build Kotlin-based SDKs that expose the platform’s capabilities to DSL authors.
• Contribute to a unified graph-based workspace model used across the platform.
• Participate in architectural discussions and long-term technical decisions.

We will be happy to have you on our team if you have: 

• Extensive JVM backend development experience.
• Extensive experience with the Kotlin programming language.
• A solid understanding of distributed systems and scalable service design.
• Prior experience with various modern storage technologies (relational databases, key-value stores, graph databases, and/or triple stores).
• Familiarity with event-driven architectures.
• The ability to prototype and iterate quickly in an experimental setting.
• A passion for clean code and maintainable systems.
• The ability to work effectively in a distributed team.

We’ll be especially thrilled if you have: 

• Experience with Kotlin Multiplatform.
• Hands-on work experience with compiler plugins or meta-programming.
• Experience building collaborative editing or reactive data systems.
• Experience building DSLs, IDEs, and language processors.