Senior Fullstack - European Union - OnHires

Deskripsi

Location: Remote

Employment: Full-time, B2B contract

Language: English

About the Company

The hiring company is an independent product-based SaaS organization with a portfolio of 10+ in-house B2C digital products. The company builds and scales its own products - no outsourcing, no external clients, and no investor pressure.

About the Role

The company is seeking a Senior SDE Fullstack who will take full hands-on ownership of backend and frontend feature development, contribute to architecture decisions, ensure performance, and maintain code quality across a modern SaaS environment.

This is a senior individual contributor role, fully hands-on - without people-management responsibilities.

What You'll Do

Hands-On Engineering (Backend & Frontend)

• Build and deliver complex features end-to-end using , NestJS, , , TypeScript.
• Design and implement scalable backend services and secure REST APIs.
• Develop performant frontend components, SSR flows, routing, and state management.
• Write clean, maintainable, well-tested code.
• Participate in architectural discussions within the product team.

Performance, Reliability & Observability

• Implement and refine logging, monitoring, and alerting (Sentry, Datadog, Groundcover).
• Troubleshoot and optimize backend and frontend performance.
• Participate in incident resolution and root-cause analysis.
• Improve system reliability, traceability, and error visibility.

CI/CD, Git & DevOps Collaboration

• Maintain and enhance CI/CD pipelines (including GitHub Actions).
• Work with DevOps to ensure consistent and stable environments across dev/staging/production.
• Manage and contribute to Git branching strategies (Git Flow or Trunk-Based Development).
• Ensure smooth, efficient, predictable deployment workflows.

Tech Stack Requirements

Must-Have

• 5+ years of professional full-stack engineering experience
• Strong production experience with:
• , NestJS
• ,
• TypeScript
• Solid PostgreSQL knowledge (data modeling, optimization, indexing)
• Strong experience with AWS services (Lambda, S3, CloudWatch, SNS/SQS or equivalents)
• Experience building secure REST APIs (JWT auth, security best practices)
• Understanding scalable architectures and distributed systems basics
• Hands-on experience with CI/CD pipelines and GitHub Actions
• Docker experience
• Experience managing Git branching strategies (Git Flow / Trunk-Based Development)
• Ability to work hybrid in Warsaw (2–3 days/week in the office)

Nice-to-Have (Strong Plus)

• Kubernetes (K8s)
• ArgoCD or GitOps workflows
• Event-driven systems (Kafka, RabbitMQ, AWS SNS/SQS)
• Infrastructure as Code (Terraform)
• Observability tooling (Sentry, Datadog, Groundcover)
• Experience with design systems / Storybook
• Experience with internal utilities or shared packages
• Experience with test automation frameworks (Playwright or similar)

Key Performance Indicators (KPIs)

• Reliable end-to-end feature delivery
• Architecture clarity and maintainability
• Production stability & incident resolution speed
• CI/CD stability and deployment quality
• Code quality, documentation, and testing discipline

What the Company Offers

• Competitive compensation
• 22 paid vacation days + national holidays
• Annual learning & development budget (courses, certifications, conferences)
• Opportunity to contribute to a fast-growing multi-product SaaS environment
• Modern technology stack with minimal legacy
• Hybrid work model with a Warsaw-based office
• Senior, autonomous engineering culture focused on product impact

Interview Process

1. External recruiter call (30 min) – introduction, expectations
2. Recruiter Interview (prescreen, scorecard, expectations)
3. Technical Interview
4. SDE Challenge
5. Second Technical Interview
6. HR Interview (Professional skills, ways of working, cultural philosophy)