Senior Application Engineer: Scale FinTech APIs & Architecture

Mollie; Lombardia; On-site; EUR 90,000 - 130,000; Full time

Job summary

Mollie in Italy invites a Senior Engineer to join our Milan hub and help shape the future of payments products used by thousands of European businesses. You will design and scale large-scale systems, develop APIs and services, and lead architectural decisions across cross-functional teams.

We value strong communication, problem solving, and a product-first approach. Relocation support is not offered outside Europe.

Qualifications

• 6+ years of experience building large-scale applications.
• Experience with Java or PHP; Go, C#, or Python also valued.
• Proven track record in leading architectural decisions and technical initiatives.
• Excellent communication across stakeholders and teams.
• Creative problem-solving and product-first thinking.

Responsibilities

• Build large-scale systems capable of handling high transaction volumes.
• Design, develop, and maintain APIs and services across Mollie engineering teams.
• Lead architectural decisions and drive engineering excellence.
• Resolve complex technical problems and improve processes.
• Document knowledge to enable domain-wide sharing.

Skills

Large-scale systems

Architectural leadership

APIs & services

Cross-functional collaboration

Java/ PHP focus

Tools

Java

PHP

Go

Python

C#

Job description

Mollie in Italy invites a Senior Engineer to join our Milan hub and help shape the future of payments products used by thousands of European businesses. You will design and scale large-scale systems, develop APIs and services, and lead architectural decisions across cross-functional teams.

We value strong communication, problem solving, and a product-first approach. Relocation support is not offered outside Europe.