Senior Back End Developer Jobs in Kansas (NOW HIRING)

About the team:

The Commercial Systems and Intelligence squad is a newly formed team within SumUp's Acquisition Mission under the Run & Grow tribe. We sit at the intersection of data, backend engineering, and sales operations, building the infrastructure that powers how SumUp attributes merchant acquisition, calculates commissions, and understands the full lifecycle of every merchant.

Today, these processes are largely manual. We're here to change that, automating what's opaque, and building systems that sales representatives, leadership, and analysts can actually trust. You'll join at the very beginning, helping to shape how the squad works, the architecture it builds on, and the standards it holds itself to.

What you’ll do:

Aggregating data from across the SumUp ecosystem to determine which acquisition channel or sales agent drove a merchant to take a valuable action (e.g. signing up, adopting a product)

Establishing data models, API contracts, and rule definitions that automate existing manual commission workflows for field and tele-sales agents, partnerships and merchant referrals

Build the Lifecycle Event Log in close collaboration with the Merchant Intelligence squad. A centralized store of curated merchant lifecycle events (signups, product usage, verification, purchases) used across attribution, recommendations, customer support and sales

Build internal backoffices and APIs for sales representatives and leaders to monitor commission and modify commission plans, manage portfolios and resolve disputes

Define and document API contracts, schemas, and integration patterns that other engineering teams can adopt confidently

Establish best practices for testing, observability, and incident response within a newly formed squad

Use AI and agentic coding tools deliberately, to scaffold services, write tests, explore unfamiliar code, and draft documentation while maintaining full accountability for what gets shipped

You’ll be great for this role if you:

Bring a strong backend engineering background in Go, or are a typed-language generalist ready to ramp up quickly

Have designed APIs and distributed systems with clear contracts, versioning, and integration patterns

Are fluent in relational and analytical databases (PostgreSQL, Snowflake) and comfortable making the right choice for the right use case

Have built Kafka-based, event-driven systems and understand event sourcing and CDC patterns

Have experience in auditable, high-trust systems where every decision must be traceable — fintech, payments, or similar domains

Have built services from scratch in greenfield, early-stage squads with limited prior context, and are energized, not unsettled, by that challenge

Have experience with testing, observability, and incident response practices and treat them as first-class concerns, not afterthoughts

Are resourceful and adaptable, you take end-to-end ownership, do more with less, and adjust quickly as priorities shift

Can bridge technical and non-technical audiences, translating fuzzy problems into clear engineering work and explaining trade-offs to engineers and sales stakeholders alike

Are pragmatic, you know when good enough ships value and when something genuinely needs to be done properly

Have mentorship instincts, you raise the bar for the people around you, not just your own output

Why you should join SumUp:

Opportunity to work with SumUppers globally on large-scale fintech products used by millions of businesses worldwide, from our Berlin office. This involves an office-first setup

Commitment to Diversity and Inclusion: Be part of a workplace that values and promotes diversity, fostering an inclusive environment where everyone's perspectives are respected and embraced

A dedicated annual L&D budget of €2,000 for attending conferences and/or advancing your career through further education

Enrolment onto our VSOP program: You will own a stake in SumUp’s future success

A corporate pension scheme where we match up to 20% of your contributions

30 Days Sabbatical: Enjoy the unique opportunity to take a well-deserved break with our 30 days sabbatical benefit after completing 3 years of employment with SumUp

Referral Bonus: Earn additional rewards by referring talented individuals to join the SumUp team

Numerous other benefits such as Urban Sports Club subsidy, Kita placement assistance, relocation assistance, subsidised office lunches

SumUp is an Equal Employment Opportunity employer that proudly pursues and hires a diverse workforce. SumUp does not make hiring or employment decisions on the basis of race, colour, religion or religious belief, ethnic or national origin, nationality, sex, gender, gender identity, sexual orientation, disability, age or any other basis protected by applicable laws or prohibited by Company policy. SumUp also strives for a healthy and safe workplace and strictly prohibits harassment of any kind.

About us:

Be empowered to do more that matters.

At SumUp, we're on a mission to empower small businesses across the globe by providing simple and affordable tools that allow them to thrive. Today, over 4 million businesses in 36 markets rely on SumUp as their financial partner to manage payments, finance and customer relationships.

Our commitment to small businesses is reflected in our diverse team of over 3,000 SumUppers from over 90 nationalities, united by global collaboration and an innovative mindset. Our core values lay the foundation for who we are and what we stand for, shaping our work culture and driving our success. We foster inclusivity and a continuous learning culture, providing a safe space for personal and professional growth. Our differences make us unique and strong as we strive to create an environment where everyone belongs and feels supported, no matter how they identify.

SumUp is proud to be an Equal Employment Opportunity employer, actively seeking and embracing diversity in our workforce. We don't make hiring or employment decisions based on race, colour, religion or religious belief, ethnic or national origin, nationality, sex, gender, gender identity, sexual orientation, disability, age or any other basis protected by applicable laws or prohibited by company policy. Our commitment extends beyond recruitment to creating a safe and respectful workplace where harassment of any form is strictly prohibited.

Explore career opportunities with us and join a team driven by collaboration, innovation, and a shared vision of creating a world where everyone can build a thriving business. Discover more about our vibrant and inclusive work culture and how we work on our careers website , and follow our journey on LinkedIn Opens in new window and Instagram Opens in new window .

Job Application Tip

We recognise that candidates feel they need to meet 100% of the job criteria in order to apply for a job. Please note that this is only a guide. If you don’t tick every box, it’s ok too because it means you have room to learn and develop your career at SumUp.