Senior Backend Developer (Services)

Stack

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 reliability through idempotency, fault tolerance, and error handling
• ▹Design and integrate external APIs, handling retries and edge cases
• ▹Implement webhooks, callbacks, and retry mechanisms
• ▹Write unit and integration tests
• ▹Take end-to-end ownership of services

Requirements

• ▹5+ years 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, retry strategies
• ▹Strong testing practices
• ▹Ability to work with legacy systems

Nice to have

• ▹Experience with PHP, Perl, or JavaScript
• ▹Familiarity with Kafka, Redis, or event-driven architectures
• ▹Exposure to CI/CD, Docker, and Kubernetes
• ▹Experience in fintech, payments, or e-commerce domains
• ▹Knowledge of 3DS, tokenization, or payment gateway integrations

Soft skills

About the company

payabl. is a licensed financial company providing global payments and multi-currency banking solutions through a unified platform.