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For Companies At a Glance
- Tasks: Join us as a Backend Developer to build and scale our AI-powered SaaS platform.
- Company: Synthesized is revolutionising software testing with AI, trusted by major global companies.
- Benefits: Enjoy hybrid work, generous pay, personal development budget, and 33 days paid leave.
- Why this job: Shape architecture, own features, and collaborate in a friendly, innovative environment.
- Qualifications: Experience in Kotlin/Java, Spring Boot, PostgreSQL, and CI/CD tools required.
- Other info: Work in a vibrant Shoreditch office with great snacks and a supportive team.
The predicted salary is between 36000 - 60000 £ per year.
About Us
Synthesized is transforming how the world tests software with AI. Trusted by global leaders like Deutsche Bank, UBS, and the European Commission, our AI-powered platform enables teams to generate high-quality test data and test cases in seconds—slashing costs, accelerating delivery, and eliminating reliance on production data. We are a VC-backed company supported by top investors. With strong traction across financial services, healthtech, and telecom, and a $90B+ market in sight, we are scaling fast in 2025 and beyond.
The Role
We’re looking for a Backend Engineer (Kotlin) to evolve and scale the control-plane of our SaaS platform. With customer adoption climbing, we need extra fire-power to extend core services and keep pace with new feature demand. Reporting to the Backend Team Lead, you’ll build services that power everything the UI depends on. You’ll work closely with Product Management on feature design and pair with frontend engineers. The role offers plenty of scope to shape architecture, own features end-to-end, and put your stamp on architectural decisions that drive the product forward.
Key Responsibilities
- Design, implement and maintain Spring Boot services in Kotlin, with a focus on clean architecture and resilience.
- Model data in PostgreSQL, own schema migrations with Liquibase, and access data through jOOQ.
- Treat the OpenAPI contract as the single source of truth. Co-author, review and enforce it across teams, automate server/client generation.
- Practice shift-left testing: write unit and integration tests alongside your code.
- Practice documentation as code: write documentation for new features alongside your code.
- Contribute to and refine our CI/CD workflow on GitHub Actions.
- Collaborate daily with the Product Manager, Team Lead and frontend engineers to de-risk stories, clarify edge cases and deliver iterative value.
- Participate in code reviews and architecture discussions, sharing knowledge and mentoring when opportunities arise.
- Help monitor production with logs/metrics, triaging incidents and feeding learnings back into design and tests.
About You
- Professional experience building Kotlin (or Java) services on Spring Boot in production.
- Solid knowledge of PostgreSQL schema design, indexing, SQL queries and migration tools (Liquibase or similar) and fluency with jOOQ or similar tools for type-safe data access.
- Comfortable writing tests (JUnit, Testcontainers, MockMVC) and using code-coverage metrics to guide improvements.
- Hands-on with OpenAPI / Protobuf and code-generation workflows; you value strongly typed contracts between services and UI.
- Familiar with GitHub and GitHub Actions (or similar) for CI/CD and environment automation.
- Understanding of cloud-native patterns (containers, REST/gRPC APIs, observability).
- Good grasp of distributed-systems pitfalls, which is relevant to our remote-agent/control-plane topology.
- Practical experience with performance profiling and JVM tuning is a plus.
- Understanding basics of front end development (full stack skills) is a strong plus.
- Clear communicator who enjoys whiteboarding with product and frontend peers and can explain trade-offs to both technical and non-technical stakeholders.
- Continuous learner who values clean code and incremental delivery.
What We Offer
- Wonderful office in the heart of Shoreditch, hybrid 3-days.
- Generous cash compensation and share options.
- Flexible work hours.
- Personal development budget (coaching, courses, events).
- Comprehensive health, vision, and dental plan coverage.
- 33 days paid leave per year including flexible national holidays.
- Snacks and drinks provided weekly.
- Working alongside great people in a friendly and respectful environment.
Backend Developer (Kotlin) employer: Synthesized
Contact Detail:
Synthesized Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Backend Developer (Kotlin)
✨Tip Number 1
Familiarise yourself with Kotlin and Spring Boot if you haven't already. Since the role specifically requires experience in these technologies, consider building a small project or contributing to open-source projects that utilise them. This hands-on experience will not only boost your confidence but also give you practical examples to discuss during interviews.
✨Tip Number 2
Understand the importance of clean architecture and resilience in backend development. Research best practices and design patterns that are commonly used in Kotlin applications. Being able to articulate your understanding of these concepts will demonstrate your readiness for the role and your commitment to quality code.
✨Tip Number 3
Get comfortable with PostgreSQL and tools like Liquibase for schema migrations. You might want to set up a local database and practice writing SQL queries and managing schema changes. This will help you feel more prepared to discuss your experience with data modelling and migrations during the interview process.
✨Tip Number 4
Brush up on your knowledge of CI/CD workflows, particularly with GitHub Actions. Familiarity with automating deployment processes can set you apart from other candidates. Consider creating a simple CI/CD pipeline for a personal project to showcase your skills and understanding of this crucial aspect of modern software development.
We think you need these skills to ace Backend Developer (Kotlin)
Some tips for your application 🫡
Tailor Your CV: Make sure your CV highlights your experience with Kotlin, Spring Boot, and PostgreSQL. Include specific projects where you've implemented these technologies, showcasing your ability to design and maintain services.
Craft a Compelling Cover Letter: In your cover letter, express your enthusiasm for Synthesized and their mission. Mention how your skills align with the role's responsibilities, particularly in building resilient services and collaborating with cross-functional teams.
Showcase Relevant Projects: If you have any personal or professional projects that demonstrate your expertise in backend development, especially using Kotlin and Spring Boot, include them in your application. This can set you apart from other candidates.
Prepare for Technical Questions: Anticipate technical questions related to backend development, such as your experience with CI/CD workflows, testing practices, and cloud-native patterns. Be ready to discuss your approach to problem-solving and architectural decisions.
How to prepare for a job interview at Synthesized
✨Showcase Your Kotlin Expertise
Make sure to highlight your professional experience with Kotlin and Spring Boot during the interview. Be prepared to discuss specific projects where you've implemented these technologies, focusing on clean architecture and resilience.
✨Demonstrate Your Database Skills
Since PostgreSQL is a key part of the role, be ready to talk about your experience with schema design, indexing, and SQL queries. You might even want to prepare a few examples of how you've handled schema migrations using Liquibase or similar tools.
✨Emphasise Collaboration and Communication
This role involves working closely with product managers and frontend engineers, so be sure to share examples of how you've successfully collaborated in past projects. Highlight your ability to communicate technical concepts to both technical and non-technical stakeholders.
✨Prepare for Technical Questions
Expect to face questions related to distributed systems, performance profiling, and JVM tuning. Brush up on these topics and think of scenarios where you’ve encountered challenges and how you overcame them, as this will demonstrate your problem-solving skills.
