Senior Backend Engineer (f/m/x)

Tomorrow GmbH; Hamburg; Vor Ort; EUR 56.000 - 62.000; Teilzeit

Zusammenfassung

Tomorrow GmbH is seeking a Senior Backend Engineer to shape services at the heart of sustainable finance. You will work on a JVM backend (Kotlin/Java, Spring Boot) in a cross-functional team, building secure, well‑tested services for banking, transactions and investing.

Collaboration with AI tooling and a pragmatic, collaborative culture are key. You will design and evolve backend domains, improve testing and observability, participate in releases, and mentor teammates while maintaining a high

Qualifikationen

• Experience delivering backend features from idea to production.
• Proficient in Kotlin/Java on JVM with Spring Boot.
• Strong in event-driven systems and data modelling.
• Mentors teammates and reviews code constructively.
• Excellent communication in English.

Aufgaben

• Design, build and evolve backend services for banking, transactions and investing.
• Model complex financial domains with clean architecture.
• Raise testing, reliability and observability standards.
• Participate in code reviews, incidents and safe releases.
• Develop and share AI harness tooling with the team.

Kenntnisse

Backend engineering

Kotlin

Java

Spring Boot

Event-driven

Mentoring

English fluency

Tools

Spring Boot

Kafka

PostgreSQL

Jobbeschreibung

The role

We have big plans for Tomorrow. Our vision: establish sustainable finance at the heart of society. That's a hell of a lot of work, so let's get started.

Behind our banking app is a backend that moves real money for real people, safely and every single day. As a Senior Backend Engineer (f/m/x) in a cross‑functional product team, the people behind banking, transactions, and investing, you help shape the services at the heart of it. You'll work on a JVM backend (Kotlin and Java, Spring Boot) built around clean domain modelling, event‑driven services and a high bar for quality, in a regulated financial environment where correctness and trust are not optional.

You will collaborate closely and proactively with other backend and mobile engineers, designers and business owners in an agile setting with regular release cycles. Our flat organisational structure and streamlined decision‑making promote a practical, collaborative atmosphere where your input shapes the architecture, how we work, and the people around you.

We build in collaboration with AI. Coding tools live in our repositories with guardrails and human review, and you stay accountable for what ships. We want someone who directs these tools well, stays critical of their output, and helps the team level up: building and sharing our AI harness, the reusable tooling and guardrails around the models, rather than keeping it to themselves.

Your responsibilities will include:

• Designing, building and evolving backend services in our product domain (banking, transactions, investing)
• Modelling complex financial domains cleanly and keeping our architecture healthy as it grows
• Raising the bar on testing, reliability and observability, and helping others do the same
• Taking part in code review, incident management and safe, well‑coordinated releases
• Using and improving our AI harness, and sharing what works with the wider engineering team

What we’re looking for

• Experience taking features or epics from idea to production You’ve been responsible for a meaningful part of a product, working closely with others to get there.
• Backend depth in production. Several years building and running production backend services on the JVM (Kotlin and/or Java with Spring Boot), including event‑driven systems (e.g. Kafka), PostgreSQL, and testing as a habit.
• You make teams better. A clear communicator who reviews, pairs, mentors and disagrees constructively.
• You work well with AI. Comfortable directing AI coding tools, reviewing their output critically and keeping ownership of what ships. Bonus if you've built or shared reusable tooling (an "AI harness") that lifted a team.
• Fluent English, our company language. German is not required.
• You support the idea of creating a better future for everyone by using money as a force for good.
• Bonus: experience in a regulated or safety‑critical domain (fintech, banking, payments, health).

What we offer

It will be fun too, we promise! Together with more than 50 like‑minded colleagues, you will work every day to win people over to sustainable finance. Our culture is based on our values, our active new work philosophy and clear, ambitious goals. But the best way to get to know us is to come and meet us and experience Tomorrow for yourself.

Salary

This is an 80% (32h per week) role. 56,000–62,400 EUR gross per year, which is 80% of our full‑time band of 70,000–78,000 EUR for this level. Transparency is Queen (and King). This is why we indicate a salary range for all jobs. Once we have got to know you better in an interview, we will be able to assess you individually and find out where you fit in our transparent salary matrix.

You want to work remotely?

We want to give everyone at Tomorrow the opportunity to organise their personal life and working hours flexibly and in keeping with their own requirements. Working from home and mobile work are integral parts of our remote‑friendly work culture. At the same time, we believe in the huge advantages of meeting up and working together in person, so we ask you to come into our Hamburg office regularly, at least once every two weeks. The office is available to you any time. It is wheelchair‑accessible, has ground‑level access and offers flexible options for designing your workspace.

Your contact at Tomorrow

Laura