Senior Backend Python Engineer (Core Gateway)
On-siteVilnius, Vilnius, Lithuania
Job Summary
Senior Backend Engineer to maintain and extend a Perl-based payment gateway while designing and building a next-generation Python microservices platform. You will support, debug, and add features to the legacy gateway during ongoing migration, while modernizing server-side components in Python for high performance and scalability. Responsibilities include integrating third-party APIs and external payment services across legacy and modern layers, collaborating in an Agile environment, understanding business logic and user impact, upholding high code quality, driving CI/CD pipelines, containerization, and cloud deployments with DevOps. The role emphasizes reliability (target 99.9%), production-grade systems, and a product-focused mindset for a payments platform based in Vilnius, Lithuania.
Required Qualifications
- 5+ years backend engineering experience with strong Python mastery (AsyncIO and FastAPI preferred)
- Experience with Perl or eagerness to learn and work within Perl production code
- Solid experience integrating third-party APIs and understanding of webhooks, callbacks, and retry policies
- Experience with CI/CD pipelines (GitLab preferred), Docker containerization, and familiarity with AWS (Lambda, cloud services)
- Exposure to event-driven architectures (Kafka, message queues)
- Strong English communication skills (written and verbal) across multi-functional teams
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