Fullstack Software Engineer, Kafka New Helsinki, Uusimaa, Finland

Aiven; Helsinki; Hybrid; EUR 85,000 - 120,000; Full time

Benefits offered by this job

Equity plan

Hybrid work policy

Equipment provided

PD budget

Wellbeing support

Time Off policy

Country-specific benefits

Job summary

Aiven is seeking a Fullstack Software Engineer to join the Kafka Ecosystem team in Helsinki. You will build end-to-end features with Python in orchestration of managed Apache Kafka services across clouds, contribute to Karapace, and develop React interfaces that users interact with.

Your focus will be Python, spanning API design to the UI. You will extend Karapace, maintain connectors, review designs, and ship code via CI/CD.

Qualifications

• Strong Python skills with async/await, type annotations and tests.
• Experience contributing to React/TypeScript UI from backend features.
• Understanding of distributed systems and data consistency.

Responsibilities

• Extend and maintain Karapace: schema compatibility, REST Proxy features, OpenAPI coverage.
• Keep connectors up to date and secure: Debezium, JDBC, S3, BigQuery, OpenSearch sink.
• Collaborate on design reviews, write well-tested code, and shape technical direction.
• Ship code through CI/CD (Buildkite, GitHub Actions).
• Investigate production issues across stack and OS level.

Skills

Python (Async)

React/TypeScript

Distributed systems

API design

Linux basics

English fluency

Tools

Karapace

Confluent Kafka

AWS/GCP/Azure

CI/CD

Job description

We're a global team of over 400+ people, working together to push the boundaries of open-source technology and multi-cloud solutions. Our vision is to help developers, builders, and creators bring their ideas to life with speed and simplicity, by providing a cloud data platform that makes open-source databases, search, streaming, and application infrastructure easily accessible to everyone.

The Role

We're looking for a Fullstack Software Engineer to join our Kafka Ecosystem team. You'll build features end-to-end: production Python in the platform that orchestrates managed Apache Kafka® services across clouds, contributions to Karapace (our open-source Schema Registry and Kafka REST Proxy), and the React interfaces that put those features in front of users. Your main focus is Python; your reach extends from API design to the UI that ships with it.

What You'll Do

• Extend and maintain Karapace: schema compatibility logic, REST Proxy features such as exposing message headers in produce and consume paths, OpenAPI schema coverage, and Confluent API compatibility
• Keep the connector ecosystem healthy: upgrades and releases of connectors like Debezium, JDBC, S3, BigQuery, and the OpenSearch® sink, security fixes, and changelogs
• Participate in design and code reviews, write well-tested code, and help shape technical direction
• Ship code reliably and often through CI/CD pipelines (Buildkite, GitHub Actions)
• Investigate and resolve production issues across the stack, from async Python application code down to Linux system behavior
• Contribute to technical planning within a small team where your input directly shapes the roadmap
• Own features end-to-end: design the API, build the async Python backend, and wire up the React/TypeScript views in our console
• Use AI coding tools as part of your daily workflow to speed up development

What We're Looking For

Must have:

• Strong Python skills: you're comfortable with async/await patterns, understand event loop semantics, and write production-grade code with type annotations and tests
• Full-stack ability: you can contribute confidently to a React/TypeScript codebase and take a feature from backend to shipped UI
• Distributed systems fundamentals: you reason clearly about consistency, replication, and failure modes
• Familiarity with schema formats and evolution: Avro, JSON Schema, or Protobuf; you understand why schema compatibility matters
• Linux fundamentals: comfortable with process management and debugging at the OS level
• Fluent in AI-assisted development: you actively use AI coding tools (Claude Code or similar) in your daily workflow, including automating repetitive processes and building AI-assisted workflows
• Fluent English, written and verbal

Nice to have:

• Hands-on Apache Kafka® experience: consumer groups, offset management, and the group coordination protocol
• Kafka Connect and connector development: custom connectors, transforms, or converters
• Prior open-source contributions, on any project
• Experience with public clouds (AWS, GCP, Azure) and cloud-managed Kafka (MSK, Confluent Cloud, or Aiven for Apache Kafka®) or other cloud-native distributed systems
• Working Java knowledge, enough to contribute to Kafka Connect source/sink tasks
• Experience operating or extending a schema registry (Confluent or Karapace)
• Experience with observability tooling: distributed tracing, Prometheus metrics, structured logging

Why This Role

• Open-source at the core. A significant part of your work ships publicly as open source. Your name goes on the commits.
• Deep technical problems. Multi-format schema compatibility, connector lifecycle orchestration at scale, and UIs that make both approachable. Not a typical backend role, and not a typical frontend role either.
• End-to-end ownership. You design it, build it, ship it, and see users work with it. No handoffs across three teams.
• Direct impact. The team is large enough to tackle ambitious problems and small enough that your technical judgement still shapes what gets built.
• Helsinki, hybrid. 3 days in the office per week.

Global Benefits

Our global benefits are designed to help you thrive and grow, personally and professionally:

• Participate in Aiven's equity plan.
• Balance work and life with our hybrid work policy.
• Choose the equipment you need to set yourself up for success.
• Use your Professional Development Plan budget for learning opportunities.
• Receive holistic wellbeing support through our global Employee Assistance Program.
• Inquire about our Global Time Off Commitment (Parental and Sick Leave, as well as Personal Time)
• Enjoy country-specific benefits for our global cast.

How to Recognize and Avoid Employment Scams

There has been a rise in fake job postings used by scammers to get personal information. At Aiven, all of our emails relating to recruitment come from an @aiven.io, @greenhouse.io or @eu.greenhouse.io domain and all of our interviews are conducted by video call or in person. Our interviews will never occur via text or chat. If you're unsure of the legitimacy of a job opportunity/offer pertaining to Aiven, please don't hesitate to reach out to us at [e-mail].

Equal Opportunities

Aiven provides equal employment opportunities to all qualified employees and applicants for employment without regard to age, gender identity, national or ethnic origin, religion, sexual orientation, physical and mental ability, marital and family status or without regard to any other similar personal attributes. Aiven complies with applicable local laws governing non-discrimination in employment in every location in which the company operates. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, transfer, leaves of absence, compensation, training and any other terms and conditions related to employment.

At Aiven we are committed to providing reasonable accommodations for qualified individuals with disabilities or special needs in our working environment and job application procedures. We make all reasonable accommodations for persons with disabilities or who otherwise need support to thrive in the workplace. We are committed to continuously improving workplace accessibility. There is an option to request a discussion in the application process but if you have any questions before applying please write to us at [e-mail].