ABOUT THE ROLE

Our full-stack solution is based on modern, serverless architecture. Powered by AWS (Lambda, SQS, SNS, DynamoDB, etc.) and using NodeJS, Typescript, NestJS and React. On the guest facing side we have Next.JS and React. It’s a robust, reliable solution that’s turning heads— and continuously evolving.

In this role, you will:

● Own corporate-focused functionality across the numa ecosystem, taking responsibility for both technical direction and hands-on delivery.

● Build and drive cross-team, full-stack improvements for corporate guests and bookers in partnership with the teams that own the relevant product areas.

● Serve as a lead engineer for initiatives that span multiple verticals, systems, and user interfaces.

● Connect teams, systems, and codepaths to ensure corporate use cases are delivered as cohesive end-to-end solutions across the platform.

● Spar with Lead Engineers on technical decisions while securing buy-in for technical designs that advance the Corporate roadmap.

● Help drive the Engineering Organization’s shift towards full Agentic Engineering

ABOUT YOU

We encourage you to apply even if you don't think you meet all of the below criteria. We care most that you are excited about the role and our mission, and are willing to learn. Ideally, you have:

● AI-Native Engineer with a solid understanding of Agentic Engineering - you don’t just vibe code, you are able to confidently leverage agents to achieve your goals.

● 6+ years of professional full-stack engineering experience, with a strong track record of owning and delivering complex product improvements end to end.

● Strong experience with Next.js, TypeScript, React, React Native, and CSS, with the ability to build high-quality user-facing experiences across complex product surfaces.

● Strong experience with Node.js and API design, including designing solutions that integrate cleanly across multiple systems and domains.

● Strong experience with testing strategies, preferably including Storybook or @testing-library, MSW, and supertest.

● Strong experience with Serverless and Event Driven Architecture, preferably AWS focused.

● Solid understanding of IaC, experience with SST, is a plus.

● Proven ability to independently drive technical solutions from problem framing through implementation, coordinating effectively across multiple teams and codebases where needed.

● Strong product and business understanding, with the ability to translate requirements into pragmatic technical approaches that work across an ecosystem rather than within a single isolated scope.

● Strong ownership mindset, with the ability to identify gaps, surface dependencies and risks early, and maintain momentum in ambiguous, cross-team problem spaces.

● Good judgment in balancing speed, scalability, maintainability, and consistency when delivering solutions that span multiple verticals.

● Excellent communication and technical stakeholder management skills.

Senior Backend Engineer (Node.js / NestJS) – Greenfield Product

Castle Tech GmbH – Berlin or Munich (Hybrid)

We are building a new standalone product from the ground up and are looking for a Senior Backend Engineer to help design and build the system's foundation.

In this role, you will play a key role in shaping the product's architecture, backend services, and technical direction. You will work closely with frontend engineers, product managers, and stakeholders to turn ideas into reliable, scalable backend systems.

This is an opportunity for engineers who enjoy designing systems, solving complex technical challenges, and taking ownership of meaningful projects from concept to production.

What You’ll Work On

• Build and maintain scalable backend services using Node.js and NestJS

• Design a clean system architecture for a new production product

• Take ownership of features from concept through deployment

• Define and implement APIs, services, and backend infrastructure

• Collaborate with frontend engineers, product managers, and designers

• Establish development standards, CI/CD pipelines, and engineering best practices

• Mentor other engineers through code reviews and technical feedback

• Continuously improve workflows using modern tooling and AI-assisted engineering

AI-Augmented Engineering

AI is part of how we work.

We expect engineers to actively use modern AI tools to improve development speed and quality, while maintaining strong engineering judgment.

You should be comfortable:

• Using AI-assisted coding tools in your daily workflow

• Writing effective prompts and critically evaluating AI output

• Identifying AI limitations and failure modes

• Exploring modern AI-driven development workflows

This role is for engineers who see AI as a tool to enhance engineering, not replace good engineering practices.

Your Skills

Must Have

• 5+ years of backend engineering experience

• Strong experience with TypeScript, Node.js, and NestJS

• Experience designing scalable backend architectures

• Strong understanding of software design principles and maintainable systems

• Experience with relational databases (PostgreSQL or similar)

• Experience working with Git, CI/CD pipelines, and Docker

• Experience mentoring or supporting other engineers

• Experience working in agile teams (Scrum or Kanban)

• Strong communication skills in English

Nice to Have

• Experience with microservices or event-driven architectures

• Experience building greenfield or standalone products

• Familiarity with AI-related components such as RAG or vector databases

• Experience integrating AI services or data-driven systems

• Conversational German

What You’ll Own

As a Senior Engineer, you will play a key role in shaping both the technology and engineering culture.

You will:

• Design backend systems with clear service boundaries and scalability in mind

• Identify technical risks early and propose effective solutions

• Contribute to architecture discussions and system design

• Improve the team’s engineering standards and productivity

• Mentor engineers and contribute to technical decision-making

• Deliver high-impact backend features aligned with product and business goals

Why Join Castle Tech?

• Build something new – work on a greenfield product from the beginning

• Real technical ownership – influence system design and architecture

• Modern engineering environment – Node.js, NestJS, and modern tooling

• AI-forward engineering culture

• Hybrid work model – office and remote options in Berlin or Munich

• Your gear, your choice – MacBook or Windows with the tools you prefer

• Growth and development – structured onboarding and coaching

• Collaborative team – ambitious engineers who enjoy building great products

Your Role 

You will join our EXP Squad, building the customer-facing APIs and backend systems that power how enterprise customers manage and automate their IoT connectivity. These are production systems that directly impact adoption, scalability, and reliability. 

As a Senior Software Engineer, you will operate at the intersection of product thinking and technical excellence. You will not just implement tickets, you will own features end to end. From early discovery and architectural design to rollout and iteration, you will shape scalable, secure, and extensible systems. 

Our core stack includes TypeScript, Node.js, and NestJS, running on AWS with Infrastructure as Code.

Your Impact

• Design and deliver scalable, customer-facing backend capabilities from architecture to production.
• Drive API and system design decisions with long-term scalability, security, and maintainability in mind.
• Collaborate closely with Product, Design, and other engineering teams to translate complex requirements into clean technical solutions.
• Improve reliability, observability, testing practices, and architectural standards within your domain.
• Contribute to mentoring, hiring, and raising the engineering bar within the team. 

Your Skills

• Strong experience building scalable backend systems with TypeScript and Node.js, ideally using NestJS.
• Proven track record designing and evolving REST APIs in production environments.
• Solid experience with AWS and Infrastructure as Code, especially Terraform.
• Hands-on experience with data modeling and performance optimization in SQL or NoSQL databases.
• Demonstrated ability to own features end to end and make sound architectural trade-offs. 

At JetBrains, code is our passion. Ever since we started in 2000, we have strived to make the strongest, most effective developer tools on earth. Our tools speed up production by automating routine checks and corrections, freeing developers to grow, discover, and create.

We are looking for a talented Full Stack Engineer to join our team and help build an innovative agentic-driven product. In this role, you’ll work across the entire stack – frontend, backend, and cloud infrastructure – designing, developing, and maintaining high-quality features. You’ll collaborate closely with product managers, designers, fellow engineers and AI-agents to deliver scalable, reliable, and user-friendly solutions.

Our tech stack:

• Primary: TypeScript, Node.JS, Nest.JS, React, Vitest (no legacy tech)
• Secondary: Kotlin/Java (for some backend services)

In this role, you will: 

• Design, develop, and maintain end-to-end features across the frontend and backend.
• Collaborate with product and design teams to translate user needs into technical solutions.
• Write clean, efficient, and well-documented code.
• Integrate our product with internal and external APIs and services.
• Contribute to architecture decisions, scalability, and performance improvements.
• Participate in code reviews to ensure quality and best practices.
• Debug, troubleshoot, and resolve issues quickly.
• Optimize applications for speed, usability, and scalability.
• Stay up to date with emerging technologies, tools, and industry trends.
• Continuously improve development processes and practices.

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

• 6+ years of proven experience as a Full Stack Engineer or in a similar role.
• Solid engineering and architecture skills and ability to build reliable solutions.
• Focus on customer-oriented delivery and understanding of user needs and requirements.
• Deep understanding of backend & frontend development.
• Proficiency in multiple programming languages (e.g. TypeScript, Kotlin, Java, Python).
• Experience with relational and/or NoSQL databases (e.g. PostgreSQL, MongoDB, and MySQL).
• Understanding of cloud platforms (e.g. AWS, GCP, or Azure) and containerization (Docker or Kubernetes).
• Proficiency with version control systems (e.g. Git).
• Experience with testing frameworks (e.g. Jest, Vitest, and Playwright).
• Familiarity with authentication, authorization, and security best practices.
• Experience with AI agent development
• Strong problem-solving skills and attention to detail.
• Excellent communication and collaboration abilities.
• A bachelor’s degree in computer science or engineering (or equivalent practical experience).

Why join JetBrains?

• Strong base salary. We offer competitive pay that reflects your skills and experience.
• Flexible work location. Enjoy the freedom to work from home or from the office.
• Remote work. Spend up to 30 days per year working remotely from abroad.
• Extra time off. More days to relax, recharge, and do the things you love.
• Medical insurance allowance. Enjoy peace of mind for you and your family.
• Learning and development opportunities. Access to conferences, courses, and language classes.
• Relocation support. We help make your move as smooth and stress-free as possible.
• Language classes. Pick up the local language or sharpen your English skills.
• Fuel your day. Enjoy a hot meal or receive a lunch allowance on workdays.
• Mental health support. To help you feel your best, we provide easy access to professional mental health services.
• Sports benefit. Enjoy an on-site gym or sports club stipend.
• Internal events. Join company-wide celebrations and team gatherings.
  *Some benefits may vary depending on location.

#LI-IM1