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(Senior) Backend Developer - eCommerce

Sofia · Engineering

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We are the leading mobile point-of-sale (mPOS) company in Europe. We started out 6 years ago and built our payment service from scratch to shake up the industry and wake up the entrepreneur within anyone. We created a unique device that allows small merchants to accept card payments anywhere. Our vision as a global FinTech company is to build the first-ever global card acceptance brand, and we are well on our way as small businesses in over 31 countries around the world rely on SumUp to get paid.

We are looking for strong candidates that have interest in helping us get there and building great products along the way. If you feel like one of these people, our office in Sofia is hiring for the position of a (Senior) Backend Engineer - eCommerce.

In this role, you will have the chance to be a part of a new business venture building the eCommerce business of SumUp from the ground up, allowing you to be the owner of your work, take decisions and immediately put them into practice. You will join a small cross-functional team which will provide you with the opportunity to be leading the design, implementation and release of new delightful features across various platforms and establishing the existing leading global card acceptance role of SumUp further into the “card not present” space. We are developing and expanding modern APIs and services to offer seamless customer experience to our partners and merchants by launching new payment methods, stepping into new markets and extending product capabilities.

In this role you will work on:

  • Build new consumer facing APIs or iterate over on existing APIs
  • Launch new payment methods to support global product offering
  • Integrate new payment acquirers, payment system providers and facilitators
  • Build new tools for use from our business and operations teams


You will be a great fit if you have the following qualifications:

  • Experience with Ruby, Node.js, Elixir
  • Experience developing RESTful APIs
  • Experience with RDBMS and Postgres in particular
  • Solid debugging, optimization and problem solving skills
  • Ability to iterate and ship ideas quickly
  • Data-driven approach when making decisions
  • Ability to write clear code that your teammates can understand and build upon
  • Ability to work across teams with both technical and non-technical stakeholders
  • Self-motivated, proactive and engaged attitude towards projects


  • Be part of one of world’s most exciting startups, on a mission to take over the world.
  • Competitive compensation and education budget.
  • Three days of extra vacation +1 day added every year
  • Additional Health Insurance
  • Participate in our weekly developer events, like Lunch & Learn and Hack Fridays.
  • We get together regularly for brunches, cocktail nights, football, yoga, massages and office parties.
  • At least one off-site every year, where the tech teams from Berlin, Sofia, and São Paulo gather to hack together. In the past we've gone to Germany, Bulgaria and Greece.

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, color, 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.

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