Senior Go Backend Engineer — Build FinTech APIs with AI

Qonto; Barcelona; Remote; EUR 90,000 - 130,000; Full time

Job summary

Qonto is seeking a Senior Backend Engineer in Barcelona to help build the financial infrastructure that supports 750,000+ European SMEs. You will design and maintain highly scalable APIs and robust banking services that process real money in real time, with zero room for mistakes.

You will join a mission-based team of 5–10 engineers, collaborating with product managers, designers, and other tech stacks, while contributing to a culture of ownership and continuous improvement.

Qualifications

• Proven backend development experience with large-scale web applications.
• Strong understanding of Go and Ruby and related server-side technologies.
• Fluent English and ability to work in cross-functional teams.

Responsibilities

• Design, build, deploy, and maintain services handling real financial transactions with reliability in production.
• Co-own service architecture, resilience, and scalability following Domain-Driven Design principles.
• Grow in technical leadership: lead design discussions and mentor engineers.
• Drive continuous improvement across the stack and CI pipelines.
• Contribute to discovery, make technical decisions, monitor production performance.

Skills

Backend engineering

Go

Ruby

Kubernetes

PostgreSQL

Kafka

English fluency

Tools

Kubernetes

PostgreSQL

Kafka

ELK

Go

Ruby

Job description

Qonto is seeking a Senior Backend Engineer in Barcelona to help build the financial infrastructure that supports 750,000+ European SMEs. You will design and maintain highly scalable APIs and robust banking services that process real money in real time, with zero room for mistakes.

You will join a mission-based team of 5–10 engineers, collaborating with product managers, designers, and other tech stacks, while contributing to a culture of ownership and continuous improvement.