Full Stack Engineer II

Mollie; United States; On-site; USD 120,000 - 150,000; Full time

Job summary

Mollie in the United States seeks a seasoned Full-Stack Engineer II to own product development end-to-end, spanning frontend, backend and APIs. You will shape architecture, build scalable services and collaborate with Product and Engineering to deliver the self-serve experience for partners and merchants.

You’ll work across systems, weigh trade-offs, and bring strong opinions to help evolve a high-growth payments platform.

Qualifications

• 5+ years of professional software engineering with full-stack ownership across frontend and backend.
• Strong frontend skills with React, React Native and TypeScript plus backend capability.
• Product-minded approach, curious, and able to decide in a complex space.
• Experience building embedded components for platform or infra use cases.
• Ability to navigate multiple interacting systems in a fast-paced environment.

Responsibilities

• Take end-to-end ownership of product development from idea to production, including testing and measurement.
• Design, build and maintain APIs, services and embedded components across frontend, backend and full-stack.
• Contribute to large-scale systems that handle high transaction volumes.
• Weigh product trade-offs and determine what to build and how to expose it to partners.
• Collaborate across multiple interacting systems and keep focus on partner and merchant needs.
• Challenge ideas and bring your own opinions to shape the self-serve track.

Skills

Full-stack development

React

TypeScript

Product mindset

System design

Cross-functional teamwork

Embedded components

Tools

React Native

APIs

Job description

Build with us

Since 2004, we've had one clear goal: to make payments and money management effortless for every business in Europe. Today, more than 250,000 companies use Mollie to get paid, manage money and grow – with products designed to be simple, scalable, and dependable. With 950+ Mollies across 14+ locations, we care deeply about autonomy and craft. So we work in small teams, with real ownership, and we trust you to make the right decisions. We're building for the long term, so we provide the tools you need, processes you can rely on, and a balanced work environment to help you do work you're proud of. Sound like your kind of place? Let's build together.

Your impact

Partner Experience sits inside Connect, Mollie's set of tools and APIs that let platforms and marketplaces offer payments to their merchants without friction. This team is focused on the self-serve track: helping partners find the right product, own the integration, and manage multiple sub-merchants with confidence. It is a domain in active transformation, with a broad scope and real engineering influence over how partner interactions evolve.

As an Full-Stack Engineer II on this team, you will take genuine end-to-end ownership of a product alongside a small, dedicated group. This is not a role where you implement a spec and move on. You will work across frontend, backend and full-stack, reason about system design, weigh product trade-offs before writing a line of code, and bring your own ideas to the table. The team actively encourages engineers to challenge thinking and expects the same in return.

If you thrive with broad scope, enjoy context-switching across complex systems, and want to shape a product from the ground up rather than maintain existing logic, this is the right place to do it.

What you’ll ship

• Take end-to-end ownership of product development, from shaping the idea through to building, testing and measuring performance in production.
• Design, build and maintain APIs, services and embedded components across frontend, backend and full-stack, with a focus on the self-serve integration experience including Connect activation, regular payment API exposure and multi-sub-merchant support.
• Build and contribute to large-scale systems capable of handling high volumes of transactions efficiently, thinking in system design terms rather than adjusting existing patterns.
• Weigh product trade-offs and make decisions about what to build and how to expose it to partners, working closely with the Product Manager to shape the self-serve track.
• Work across multiple interacting systems simultaneously, managing context and keeping focus on what matters most for partners and their merchants.
• Challenge ideas and bring your own. This team expects engineers to have opinions and act on them.

What you’ll bring

• 5+ years of professional software engineering experience, with genuine full-stack range. You are comfortable owning a feature end-to-end across both frontend and backend, not just shipping UI with light backend glue.
• Strong frontend engineering skills including React, React Native and TypeScript, combined with real backend capability and the ability to design and reason about more complex backend systems.
• A product mindset. You ask questions, bring curiosity, and are comfortable making decisions in a complex product space rather than waiting for a fully defined spec.
• Experience building embedded components for platform or infrastructure use cases, whether frontend, backend or full-stack.
• Comfort working across multiple interacting systems in a fast-paced, broad-scope environment where the work is sometimes vague and the context shifts frequently.
• The ability to weigh options and trade-offs to solve a problem, not just execute on what is in front of you.

Grow your way

At Mollie, growth is personal. We believe everyone should have the chance to develop their skills, explore new challenges and shape their career on their own terms.

You’ll get regular feedback and performance reviews to support your development, with fair and transparent salary reviews along the way. Many Mollies move into new roles or take on new projects to stretch themselves, and we actively hire from within to help you take the next step.

No matter if you’re aiming for promotion, exploring a different career path or building new skills, you’ll be supported with the tools, trust and opportunities to grow your way.

Unlock your full potential and join us to eliminate financial bureaucracy If you’re excited by the idea of building what’s next, for yourself and for thousands of businesses across Europe, we’d love to hear from you.

AI at Mollie

We believe in Always Be Shipping, and AI brings that philosophy to life across every team, every role, every day.

AI is core to how we build. It helps us move faster, simplify work and make smarter decisions, creating real impact for the businesses we serve. We’re looking for people who are excited to use AI to shape the future of finance with us.