Tech Lead (Fullstack - React, React Native, NestJS)

Job Description:

We are developing fitness applications for the German market.

We are looking for an experienced Tech Lead who can take ownership of both our web and mobile clients, with a strong focus on React Native, while also being deeply confident in backend architecture with NestJS.

This role is ideal for someone like Timo-type profile - a hands-on fullstack lead who can drive the team through a fast-paced startup-like delivery phase and ensure a reliable launch.

You will shape technical direction, unblock the team, and ensure that our architecture scales across web, iOS, and Android.

You will work closely with stakeholders, product, QA, and design.

You will also be responsible for pragmatic decision-making and preventing over-engineering while maintaining high quality standards.

Key Responsibilities:

- Lead the development of our fitness ecosystem across mobile and web.

- Own the technical delivery of the React Native app, including architecture, performance, reliability, and release readiness.

- Support and guide the web team working with React and modern frontend tooling.

- Design and oversee robust APIs and business logic using Node.JS and NestJS within a distributed micro-services architecture.

- Implement and maintain communication between microservices using message brokers (NATS, RabbitMQ, Kafka).

- Design and implement database schemas and data access patterns using Prisma ORM with Supabase DB.

- Drive integration with third-party services and APIs.

- Coordinate wearable and health platform integrations where applicable (Apple Health, Fitbit, Garmin).

- Implement search solutions using Typesense or similar tools.

- Ensure secure and scalable patterns across backend and clients.

- Set up and maintain CI/CD pipelines (GitHub Actions).

- Oversee deployment and maintenance on AWS (ECS, Fargate, S3, IAM).

- Implement caching strategies using Redis.

- Participate in code reviews, set engineering standards, and mentor developers.

- Collaborate on technical planning, risk management, and release strategy with stakeholders.

Requirements

- 6+ years of experience as a JavaScript/TypeScript Fullstack Developer with proven Tech Lead responsibilities.

- Strong hands-on experience with React Native in production apps.

- Strong experience with React for web and modern frontend architecture.

- Solid backend expertise with Node.JS and NestJS in distributed systems.

- Hands-on experience with message brokers (NATS, RabbitMQ, or Kafka).

- Experience with Prisma ORM and relational databases (PostgreSQL preferred).

- Good knowledge of Supabase Auth and Supabase DB.

- Experience deploying and operating services on AWS.

- Deep understanding of API design patterns and microservice communication.

- Strong proficiency in TypeScript.

- Proficiency with Docker and CI/CD (GitHub Actions preferred).

- Experience with caching mechanisms (Redis).

- Experience integrating third-party APIs.

- Good understanding of system design and ETL concepts.

- Experience with mono-repos (Turbo, Nx) and PNPM is a plus.

- Strong communication skills and ability to lead a cross-functional team.

- English B2 level required.

- German B2 or higher is a strong advantage.

Nice to Have:

- Experience with nutrition tracking, workout plans, progress tracking, and subscription models.

- Practical knowledge of mobile analytics, crash monitoring, and performance tuning.

- Experience with Apple Health and other wearable ecosystems.

- Experience working with large codebases and scaling teams.

What We Offer:

- A key leadership role in a fast-growing fitness product for the German market.

- Direct impact on architecture, product quality, and launch success.

- A pragmatic, delivery-focused environment with real ownership and autonomy.

- A team that values clear communication, speed, and high standards.