Senior Backend Developer (PHP)

• Engineer for reliability and scale: You'll design and maintain a high-availability platform that processes millions of secure transactions every day across Europe.
• Work with robust architecture: From creating and optimizing (micro)services to improving database performance, you'll contribute to a backend built for accuracy, security, and long-term maintainability.
• Be part of a focused, skilled team: Collaborate with 25+ experienced engineers, and work together in agile teams, share knowledge, and solve complex technical challenges in the world of payments.

What you'll do as a Senior Backend Developer at Online Payment Platform What started as five people, a small office, and a few nerf guns has grown into one of Europe's fastest-growing fintechs. With 150+ colleagues, offices in Delft, Berlin, and London, and Worldline as our partner, we've got the perfect mix: the power of a global leader with the energy of a scale-up.

At OPP, we build the technology that powers the next generation of e-commerce. From eBay Kleinanzeigen to Ikea, tens of millions of users rely on our systems every day. We don't just process payments, we enable platforms to accept, hold, and disburse funds securely, 24/7.

As a Senior Backend Developer, you'll be part of one of our four agile Scrum teams focused on in-platform payments, onboarding, and core product innovation. You'll contribute both strategically and hands-on: designing scalable architectures, mentoring teammates, and ensuring smooth delivery of solutions. You'll thrive in an environment that values collaboration, precision, and innovation. Our goal is clear: a future-proof platform with Fort Knox-level security, high availability, and the flexibility to support everything from traditional marketplaces to next-generation embedded payment solutions.

Projects you'll help shape

• In-platform payments: Expanding beyond traditional e-commerce to serve platforms where money moves in new ways.
• Onboarding & compliance: Develop intuitive user journeys while upholding strict security standards.
• Scalability & microservices: Transforming legacy systems into agile, modular components that can handle tens of millions of transactions across Europe, the UK and beyond.
• Beyond payments: Developing API's, web applications and tools that give platforms the freedom to grow and innovate.

Tech you'll use & how you'll lead

• You'll work with a modern stack including PHP, Laravel, Symfony, MySQL, Redis, Docker, Kubernetes, and CI/CD pipelines.
• You'll design and implement scalable, modular services built for long-term maintainability.
• You'll help shape technical strategy while mentoring junior and mid-level developers.
• You'll contribute to key architectural decisions that ensure 99.99% availability and industry-leading security standards.

Do you have experience in Scalability?, * Deep experience with PHP and MySQL in high-stakes environments.

• Mastery of Laravel and/or Symfony frameworks.
• Proven track record with high-traffic platforms and microservices.
• You don't need to look up CI/CD, Docker, or Kubernetes, they're second nature to you as well as cache, queue, scalability, optimization and performance solutions. If you're just as comfortable with Redis, Queues, and scalable microservices, we might even let you choose the next game for team night.
• Ability to communicate complex technical concepts clearly with different departments.
• For this role, we are looking for someone residing in the Netherlands.

How we invest in you Great technology is as strong as the people who build it. If you bring the skills and a customer-first mentality, we'll bring the tools you need to build amazing, robust products. We also offer you:

• A total yearly salary of up to €95.000.
• A modern, flexible workplace with hybrid working.
• 24 vacation days and 2 supercharge-me-days.
• 12-month contract with the possibility of permanent extension.
• The tools you need: a MacBook, home office setup, and NS Business Card.
• An attractive bike plan if you work 24 hours or more
• A developers-only office at Lange Geer 26, within walking distance of our sales and product teams in the heart of Delft.
• A great work atmosphere with catered lunches and regular team drinks.