Senior Full-Stack Engineer — Hybrid (4-Day Week) & Impact

WelcomeTrack; Paris; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Hybrid work schedule

Health insurance (mutuelle)

Meal vouchers

Public transport subsidy

Job summary

WelcomeTrack is seeking a Senior Full Stack Engineer to design, develop, and maintain scalable server and client components. You will collaborate with a cross-functional squad to deliver features, improve system architecture, and ensure high-quality deliverables that meet technical and business goals.

You will work with Engineering Managers, Product Managers, and other engineers in an agile environment. The role emphasizes code quality, performance, security, and strong testing practices within

Qualifications

• 5+ years of professional software development with back-end and front-end experience.
• Proven experience designing scalable architectures, RESTful APIs and data models.
• Strong knowledge of relational databases and performance optimization.
• A strong testing culture with unit/integration tests (TDD preferred).
• Experience running production systems with monitoring and incident management.
• Ability to mentor engineers through code reviews and pairing.
• Professional English for international collaboration.

Responsibilities

• Design, develop, and maintain scalable back-end services and front-end apps.
• Build and optimize database schemas and data models.
• Write clean, tested code following team standards.
• Participate in code reviews and provide feedback.
• Debug production issues and implement robust solutions.
• Contribute to architecture decisions and technical docs.
• Design and implement RESTful APIs.
• Optimize performance and scalability; implement caching and async processing.
• Engage in agile ceremonies and planning.
• Collaborate with PMs, Designers and Engineers to prioritize work.
• Handle support requests and bug fixes within SLAs.

Skills

RESTful APIs

Data modeling

Relational databases

Testing culture

Production systems

Code reviews

English communication

Tools

Docker

Kubernetes

AWS

Datadog

Sentry

Elixir/Phoenix

Job description

WelcomeTrack is seeking a Senior Full Stack Engineer to design, develop, and maintain scalable server and client components. You will collaborate with a cross-functional squad to deliver features, improve system architecture, and ensure high-quality deliverables that meet technical and business goals.

You will work with Engineering Managers, Product Managers, and other engineers in an agile environment. The role emphasizes code quality, performance, security, and strong testing practices within