Senior Backend Developer


RnD Department is responsible for developing new services / products and improving the existing ones at Simplex. Owning the growth and maintenance of our Crypto onramp / offramp and Banking solutions – platforms that support millions of dollars’ worth of transactions on daily basis.
We envision the core Dev Team members as the future tech leaders and contributors to the company’s success.

As a Senior Backend Developer you will be working on creation & development of a high-end fraud detection SaaS platform micro-services & serviceless technologies on AWS and GCP cloud platforms.

In this role, you'll get to:

  • Guide & mentor the team of experienced developers;
  • Influence, define and take part in building our systems to the next level;
  • Develop scalable, real-time decision making a data-driven system by adopting the latest architectural & design principles and based on RDBMS & graph database;
  • Build systems that are highly available, hold sensitive financial data, & include safety nets to avoid hackers/fraudsters employing large-scale fraud attacks;
  • Collaborate with other team members such as Analyst’s & Data scientists.

What we're looking for: 

  • At least 6 years of backend development in Node.js or Python (Python preferred);
  • At least 3 years of hands-on work experience in software development building backend code for cloud applications;
  • Experience in various databases (Postgres/ Redis/ Elastic/ etc.);
  • Understanding of fundamental design principles for building a scalable application;
  • Multi-tasking team player & creative problem-solver, who is also able to work independently.


  • Hands-on experience in a public cloud environment (AWS, Azure, GCP);
  • Experience with Graph databases;
  • Good understanding of data structures;
  • Leadership experience (scrum master, tech lead, team leader, etc.);
  • BSC in Computer Science or similar.

What's in it for you?
You will have an opportunity to be part of a challenging Fintech industry and together with an international and talented team spread across the globe shape the future of it.

Competitive salary & Additional benefits include:

  • Cool pet friendly office in Vilnius
  • Monthly LIDL or WOLT food allowance
  • Flexibility & possibility to work from home
  • 1-month Workcation
  • Additional vacation days
  • Long-term incentive plan
  • Private health insurance (after 3 months’ probation)
  • Annual bonus depending on individual & company results
  • Space for personal & professional growth, including trainings, etc.
  • Office perks, great atmosphere & company events + a lot more to explore! 

Come join us and help define the next generation of payment services, fraud prevention and cryptocurrency.

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