Senior Backend Engineer - Secure, Scalable Java Systems

FDJ UNITED; Stockholms kommun; On-site; SEK 900,000 - 1,200,000; Full time

Job summary

FDJ UNITED is seeking a senior software engineer to lead secure backend work in a production environment. You will own authentication and session flows, design APIs, and drive reliability in distributed systems.

Bring strong Java/Spring experience, knowledge of OAuth/OpenID, and a security-first mindset. You will collaborate across product, architecture, and security to raise engineering quality and delivery confidence.

Qualifications

• Strong backend experience in Java and Spring Boot.
• Experience designing APIs and service integrations.
• Knowledge of OAuth 2.0 and OpenID Connect.
• Security-minded with OWASP awareness and secure-by-default thinking.

Responsibilities

• Develop secure, reliable backend solutions for authentication and session flows.
• Evolve backend systems to meet business and technical needs with performance in mind.
• Contribute to engineering quality via reviews, testing, and automation.
• Own design to production, breaking down work and driving delivery.
• Improve quality by early issue detection and shift-left testing.
• Collaborate with product, architecture, and security teams.

Skills

Java backend

Spring Boot

API design

Event-driven

OAuth 2.0

OpenID Connect

Secure coding

OWASP

Testing strategies

CI/CD

Code reviews

Production support

Relational DB

Performance testing

Tools

Solace

Job description

FDJ UNITED is seeking a senior software engineer to lead secure backend work in a production environment. You will own authentication and session flows, design APIs, and drive reliability in distributed systems.

Bring strong Java/Spring experience, knowledge of OAuth/OpenID, and a security-first mindset. You will collaborate across product, architecture, and security to raise engineering quality and delivery confidence.