SENIOR BACKEND ENGINEER (PAYMENTS)

Lucie Richardson AB; Stockholms kommun; On-site; SEK 669,600 - 892,800; Full time

Benefits offered by this job

Attractive salary

Equity ownership

Inclusive work culture

Job summary

Ants in Stockholm is searching for a Senior Backend Engineer specializing in payments. The ideal candidate will design and construct foundational payment infrastructure, ensuring all aspects of the transaction lifecycle are stable and efficient.

Applicants should have meaningful experience in fintech, strong technical skills, and fluency in English. The position provides an attractive salary along with equity opportunities for a pivotal role in a startup environment.

Qualifications

• Meaningful industry experience inside a payments or fintech company.
• Complete understanding of payment flows and engineering decisions.
• Working knowledge of PCI DSS at application and infrastructure level.

Responsibilities

• Design and build payment orchestration infrastructure.
• Build robust transactional architecture.
• Integrate with third-party commerce and service APIs.

Skills

Payments industry experience

Fluent English

Technical communication

Problem-solving

Agile methodologies

Education

MSc in Computer Science or Software Engineering

Job description

Who We Are

At Ants, we are partnering with a well‑funded, early‑stage startup in Stockholm to find a Senior Backend Engineer (Payments).

We are a well‑funded, early‑stage technology company on a mission to fundamentally redefine the way the world searches, discovers, and transacts, built on a philosophy that puts the user first at every step.

The user is not simply a means of transaction. They are a valued participant whose data works for them, not against them, enriching their world and their own experience within it, with them retaining full control.

Our mission is underpinned by proprietary, patent‑pending technology built on a novel engine and system.

The Problem You Will Be Solving

The internet was built to inform the many, not to serve the individual. Platforms optimize for engagement, extraction, and consumption at global scale. AI has made this model even more efficient, with the user still largely remaining the input, not the full beneficiary.

The problem is not information. The world has never had more. The problem is that people give away a lifetime of data without receiving the personalized experience it should enable.

People should not have to search. They should simply find.

Who You Are

• Highly talented and motivated to build products with people, for people
• You thrive in zero‑to‑one environments and find genuine satisfaction in creating from scratch
• A fast‑paced thinker with a relentless desire to learn, improve, and raise the standard around you
• Able to inspire, elevate, and collaborate; you make the people around you better
• A great communicator; you express complex ideas with clarity, precision, and confidence across all levels of the organization
• Able to transform ideas into working systems and technical milestones with light speed and precision
• Highly ambitious and action‑driven; you thrive under pressure and find genuine energy in working at the edge of what is considered possible
• Capable of designing and building production‑grade systems in a fourth of the time most experienced and “sane” professionals would consider possible

What You Will Do

• Design and build payment orchestration infrastructure with intelligent routing, retry logic, and reconciliation across multiple external and in‑house providers
• Build robust transactional architecture that manages complex end‑to‑end flows from initiation to confirmed state with comprehensive failure handling
• Integrate with third‑party commerce and service APIs through clean abstractions that shield the rest of the platform from integration complexity
• Build digital wallet and balance management systems with high standards for accuracy, transaction history, and regulatory auditability
• Design and build enterprise billing and accounting systems that produce correct outputs at scale with strong audit trails for internal and external compliance
• Build foundational data models and event logs that ensure the entire transaction layer is fully replayable, auditable, and recoverable from any failure state

Minimum Qualifications

• Meaningful industry experience inside a payments or fintech company; Klarna, iZettle, Adyen, Trustly, Brite Payments, or an organization of equivalent domain standing
• Complete operational understanding of payment flows; every stage from authorization to reconciliation and the engineering decisions each stage requires
• Working knowledge of PCI DSS applied in practice at the application and infrastructure level
• Idempotency and correctness as default engineering habits applied from the first line of a new system, not added later
• Fluency in written and spoken English is required

Preferred Qualifications

• MSc in Computer Science or Software Engineering
• Experience with distribution, commerce, and service platform API integrations
• Demonstrated track record of delivering payment infrastructure at a pace and quality that distinguishes you in the domain
• 3‑8 years of payments or fintech infrastructure experience

What We Offer

Compensation includes an attractive salary and meaningful equity ownership for an early‑stage startup.

Equal Opportunity

We are an equal opportunity employer committed to building an inclusive, high‑performance culture where everyone can do their best work and reach their full potential. We welcome applicants of all backgrounds and do not discriminate on the basis of race, color, religion, national origin, gender, gender identity or expression, sexual orientation, age, disability, or any other characteristic protected by applicable law.

Department Software Engineering Locations Stockholm