Senior Backend Developer

At New Soul, we're redefining modern wellness by blending premium in-studio experiences with a strong digital platform that powers booking, payments, memberships, and daily studio operations. As we scale across Germany, system stability, performance, and clean integrations are business-critical - what we ship directly affects revenue, operational load, and customer experience. We run a lean team with high ownership, minimal meetings, and a pragmatic engineering culture: ship impact, keep things maintainable, avoid over-engineering, and document just enough so others can move fast with confidence.

Your Role As a Senior Backend Developer, you'll build and evolve our backend systems and integrations that support both customer-facing journeys (booking, payments, memberships) and internal operational tooling. You'll work closely with Product, Frontend, and Ops stakeholders to deliver scalable features, improve reliability, and reduce operational friction. This is a great fit for someone who can operate independently, handle ambiguity, and drive work end-to-end - from understanding the problem to shipping the solution and leaving the system cleaner than before.

Your Responsibilities

• Build and maintain backend services that power core platform capabilities (e.g., booking availability, memberships, payments logic, operational workflows).
• Design, implement, and evolve internal and external APIs (GraphQL/REST), ensuring consistency, performance, and long-term maintainability.
• Own technical execution for complex projects with unclear dependencies - align early, de-risk quickly, deliver steadily.
• Proactively identify bottlenecks, failure points, and technical debt; propose pragmatic fixes and execute them.
• Create proof-of-concepts (POCs) where needed to validate approaches before implementation.
• Collaborate closely with frontend engineers, product, and operations teams to ensure smooth end-to-end delivery.

Your Tasks

• Initiate and maintain lightweight but useful technical documentation:
• API documentation (e.g., Swagger, ReadMe.io)
• Infrastructure and Component Diagrams (at a level less detailed than L4 but more comprehensive than nothing).
• Improve and operate within a custom / minimal-framework environment - focusing on incremental improvements and clarity rather than relying on heavy frameworks as Symfony.
• Take ownership of delivery for multiple parallel initiatives, balancing urgency with quality., + Languages and Tools: PHP8+, MySQL, Redis (Equivalents), RMQ/Kafka, Kubernetes
• Testing Frameworks: PHPUnit
• APIs and Integrations: GraphQL, REST APIs, OpenAPI
• Version Control and CI/CD: Git, Github Actions

What You'll Get

• Real ownership and impact: Your work directly improves customer experience and studio operations and is used by thousands of customers across Germany.
• Pragmatic engineering culture: High trust, Flexible working hours, Minimal mandatory meetings.
• Engineers get a top-spec laptop, using the platform of their choosing.
• The choice of a range of Company Benefits (50% of all products and services), Urban Sports Club membership and coverage of Deutschland-Ticket.

Must-Have Skills

• 5+ years of professional experience with PHP, with continued interest in its application.

• A self-organized, technically skilled individual who avoids over-engineering solutions.

• Advanced stage of growth in understanding the balance of complexity vs. simplicity (e.g., past the "valley of despair" on the Dunning-Kruger effect curve).

• Proficient in integrating and building internal and external APIs.

• Experienced in starting projects from scratch, with strong architectural design skills.

• Comfortable joining a project as an Individual Contributor (IC) rather than enhancing an existing system gradually.

• Capable of independently managing and delivering tasks, systems, and contributions that align with team goals.

• Strong communication skills, with a results-oriented and efficiency-driven mindset.

• Proficient English speaking, German is a plus Nice-to-Have Skills

• Experience with other languages (especially Golang).

• Basic DevOps knowledge (Kubernetes, Terraform) and comfort working with infra-adjacent topics.