Senior Backend Engineer - Fintech, Blockchain & APIs

Dfns; Paris; Hybrid; EUR 125,000 - 214,000; Full time

Benefits offered by this job

Healthcare

Stock options

Remote-first

Job summary

Dfns is seeking a Senior Software Engineer to design and scale core backend services powering our fintech platform. You’ll build REST APIs, microservices, and data infrastructure, and push for production-readiness, security, and performance.

You’ll work with product, security, and infrastructure teams to solve complex problems across wallets and cross-chain integrations, contributing to architecture decisions and improving developer workflows.

Qualifications

• 8+ years of backend software engineering experience in fintech or finance.
• Strong in TypeScript, proven track record building scalable APIs and dev tools.
• Expertise with databases (PostgreSQL, DynamoDB, NoSQL) and AWS services.
• Skilled in microservices, CI/CD pipelines, observability, and SSLDC practices.
• Familiar with public key infrastructure and backend security fundamentals.
• Strong problem-solving, clear communication, and ability to deliver under pressure.

Responsibilities

• Design, build, and maintain secure, scalable backend services and APIs (REST).
• Architect databases and microservices for performance, reliability, and growth.
• Own projects end to end: from requests, implementation to production and iteration.
• Troubleshoot complex issues, resolve performance bottlenecks, ensure resilience.
• Collaborate with product, security, and leadership on roadmap and technical direction.
• Document systems, share knowledge, and support client-facing discussions.

Skills

Backend API design

TypeScript

Scalable architectures

Databases

AWS

CI/CD

Security fundamentals

Job description

Dfns is seeking a Senior Software Engineer to design and scale core backend services powering our fintech platform. You’ll build REST APIs, microservices, and data infrastructure, and push for production-readiness, security, and performance.

You’ll work with product, security, and infrastructure teams to solve complex problems across wallets and cross-chain integrations, contributing to architecture decisions and improving developer workflows.