Senior Backend & AI Engineer (all identities)

Aimlroles; Berlin; Hybrid; EUR 78,000 - 88,000; Full time

Benefits offered by this job

Home office allowance

Meal subsidy

30 vacation days

Learning budget

Office option in Berlin

Job summary

Caspar Health is expanding its small, highly agile backend squad in Germany. You will take full ownership: designing robust Ruby on Rails services, clean APIs, and LLM-based workflows with repeatable quality checks, while collaborating closely with product and domain experts.

The role is full-time with a gross salary between €78,000 and €88,000 per year, with remote-first flexibility and a Berlin office option.

Qualifications

• Backend engineering: building and maintaining complex Rails systems.
• API design: clean APIs and data models, background jobs handling.
• System architecture: authorization, billing workflows, automated testing strategies.
• LLM practice: building LLM applications and agent workflows.
• End-to-end ownership: own feature from design to live production.
• Technical communication: collaborate with product/domain experts and articulate trade-offs.

Responsibilities

• System Architecture: Full end-to-end ownership of features across implementation, automated testing, release, and live operation.
• Backend Engineering: Development of scalable Ruby on Rails services, robust APIs, data models, and background jobs including authorization and billing workflows.
• LLM Workflows: Building and optimizing LLM applications, evaluation pipelines, and agent workflows with repeatable quality checks.
• Product Collaboration: Close partnership with Product Manager and domain experts to turn complex requirements into maintainable, high-performance software.
• Technical Reviews: Active contribution through clear technical reviews, operational monitoring, and explicit technical decision-making.
• Quality Standards: Shaping our delivery practices and modern test/engineering standards.

Skills

Ruby on Rails

API design

System architecture

LLM workflows

Ownership

Technical communication

Job description

Build intelligent backend systems that make a genuine impact in healthcare.

Caspar Health is the leading digital platform for medical rehabilitation. We empower doctors, therapists, and nursing staff to care for patients as quickly, effectively, and sustainably as possible.

To take our platform to the next level, we are expanding our small, highly agile backend squad (consisting of 3 engineers and a Product Manager). In this role, you will take full technological ownership: from designing robust Ruby on Rails services and clean API architectures to building LLM-based agent workflows with repeatable quality checks. If you are passionate about combining modern AI engineering with true purpose and highest software standards, you will thrive here.

We appreciate your expertise and wish to provide full transparency regarding the compensation range for this role. Your starting salary will be aligned with your qualifications, relevant experience, skill set, and market benchmarks. Remuneration for this position follows our internal salary bands and ranges from €78,000 to €88,000 gross annually (based on a full-time 40-hour work week).

This role is located in Germany and requires full physical presence within the country. Due to our existing payroll and social security framework, permanent remote employment from abroad is not supported. Candidates must be eligible to work in Germany and resident from their first day. Please be advised that we cannot offer visa sponsorship or relocation assistance at this time.

Responsibilities

• System Architecture: Full end-to-end ownership of your features across implementation, automated testing, release, and live operation.

• Backend Engineering: Development of scalable Ruby on Rails services, robust APIs, data models, and background jobs including authorization and billing workflows.

• LLM Workflows: Building and optimizing LLM applications, evaluation pipelines, and agent workflows with repeatable quality checks.

• Product Collaboration: Close partnership with Product Manager and domain experts to turn complex requirements into maintainable, high-performance software.

• Technical Reviews: Active contribution through clear technical reviews, operational monitoring, and explicit technical decision-making.

• Quality Standards: Shaping our shared delivery practices and establishing modern test and engineering standards across the team.

Qualifications

• Backend Engineering: Strong senior experience in building and maintaining complex systems using Ruby on Rails.

• API Design: Proven expertise in designing clean APIs, data models, and managing background job processing.

• System Architecture: Sound understanding of authorization concepts, billing workflows, and automated testing strategies.

• LLM Practice: Practical experience building LLM applications, evaluations, and agent workflows.

• End-to-End Ownership: Ability and mindset to own functionality independently from initial design to live production.

• Technical Communication: Strong communication skills to collaborate with product and domain experts and make technical trade-offs explicit.

• Remote-first with flexible working hours – office optional in Berlin-Mitte or up to 90 days a year outside of Germany

• To match this, we support you with a monthly home office allowance and an additional meal subsidy

• Plenty of time to recharge – with 30 vacation days per year

• Budget for learning & development, conferences, and coaching – tailored to your potential and growth opportunities

• High level of ownership and decision-making freedom – no micromanagement. We hire experts who know what they’re doing. #MakeAnImpact!

• Genuine collaboration – no silos, no egos. After all, we’re all working toward the same vision. #ValueFocus!

• Access to all Caspar offerings for mental and physical well-being #HealthyTogether!

• And yes – all the snacks your heart desires, group sports sessions, a never-empty drinks fridge, and a healthy dose of humor are included too

What definesus as a team

• We live diversity – it's not a marketing slogan, it's part of our everyday reality

• Feedback isn’t a tool – it’s part of our culture

• We believe that technology only makes sense when it truly helps people

• Our drive is purpose – but our standard is professionalism

Our product CASPAR Health is used in the environment of medical institutions, patients, doctors and therapists. Working with (sensitive) personal data (e.g. health data) is part of our daily work. Therefore, we require a high level of commitment to the protection of personal data from our employees in order to protect the rights of the data subjects as best as possible.

Diversity and Inclusion

At Caspar Health, we strive to provide a friendly, safe and welcoming environment for all Casparians* regardless of ethnic origin, gender, gender identity and expression, sexual orientation, limitations of any kind, physical appearance, social background, age or religion (or lack thereof).

We are looking forward to getting to know you!

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