Senior Python Backend Engineer – Fintech Services (Remote)

Payabl; Warszawa; Hybrid; PLN 240,000 - 360,000; Full time

Job summary

payabl, a fintech platform operating remotely in Poland, is seeking a Senior Python Backend Developer (Services) to architect and evolve our service layer. You will transform legacy logic into modern Python microservices and ensure reliability and maintainability at scale.

The role emphasizes hands-on coding, design ownership, and collaboration with the engineering team to deliver high-performance services and robust integrations in a fintech environment.

Qualifications

• 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 (MySQL, PostgreSQL).
• Solid understanding of API design and third-party integrations.
• Experience implementing webhooks, callbacks, and retry strategies.
• Strong testing practices (unit and integration testing).
• Ability to work with legacy systems and migrate them into modern architectures.
• Ownership mindset and ability to work autonomously within a defined architecture.

Responsibilities

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

Skills

Python

AsyncIO

FastAPI

Microservices

Relational databases

Tools

Docker

Kubernetes

CI/CD

MySQL

PostgreSQL

Job description

payabl, a fintech platform operating remotely in Poland, is seeking a Senior Python Backend Developer (Services) to architect and evolve our service layer. You will transform legacy logic into modern Python microservices and ensure reliability and maintainability at scale.

The role emphasizes hands-on coding, design ownership, and collaboration with the engineering team to deliver high-performance services and robust integrations in a fintech environment.