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Senior Backend Developer (Services)

16 hours, 27 minutes ago
Portugal, Ukraine
Contract
Senior
Backend Engineer
Software Development
CI/CD Docker E-commerce FastAPI JavaScript Kafka Kubernetes Microservices MySQL Perl PHP PostgreSQL Python Redis REST API
Apply Now
payabl.

payabl.

payabl. empowers merchants to handle payments on a global scale by offering a comprehensive solution that includes card acquiring, alternative payment methods, payment accounts, and prepaid cards.

Diversified Financial Services
51-250
Founded 2011
View All Jobs 6

Description

  • Design, build, and maintain high-performance Python microservices using FastAPI and AsyncIO.
  • Analyze legacy systems and extract business logic into modern service architectures.
  • Refactor and migrate existing modules into clean, scalable, maintainable services.
  • Ensure reliability through idempotency, fault tolerance, and robust error handling.
  • Design and integrate external APIs, including edge cases, retries, and failure handling.
  • Implement and manage webhooks, callbacks, and complex retry mechanisms.
  • Write high-quality unit and integration tests.
  • Collaborate with cross-functional teams to maintain service stability and performance.
  • Contribute to architectural discussions and continuous system improvements.
  • Own services end-to-end from design through production.

Requirements

  • 5+ years of backend development experience with strong Python expertise.
  • Deep knowledge of AsyncIO and FastAPI.
  • Experience building non-blocking, high-reliability microservices.
  • Strong experience with relational databases such as MySQL or PostgreSQL.
  • Solid understanding of API design and third-party integrations.
  • Experience implementing webhooks, callbacks, and retry strategies.
  • Strong testing practices, including unit and integration testing.
  • Ability to work with legacy systems and migrate them into modern architectures.
  • Strong analytical and problem-solving skills.
  • Ownership mindset and ability to work autonomously within a defined architecture.
  • Experience with PHP, Perl, or JavaScript is preferred.
  • Familiarity with Kafka, Redis, or event-driven architectures is preferred.
  • Exposure to CI/CD pipelines, Docker, and Kubernetes is preferred.
  • Experience in fintech, payments, or e-commerce domains is preferred.
  • Knowledge of 3DS, tokenization, or payment gateway integrations is preferred.
  • Proven experience migrating systems across technologies or paradigms is preferred.
  • Remote contractor arrangement based in Portugal or Ukraine.

Benefits

  • Remote contractor arrangement.
  • Opportunity to work on high-impact systems in a fast-growing fintech environment.
  • Chance to help modernize and scale a platform handling real-world financial operations.
  • Clear architectural direction with full ownership of implementation.
  • Collaborative environment with room to influence technical decisions.
  • Dedicated DevOps support.
  • Work on complex, real-world engineering challenges.
  • A culture that values autonomy, ownership, and engineering excellence.

Interested in this position?

Apply directly on the company website

Apply Now

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