Middle/Senior Python Backend Engineer

On behalf of our Client from Scotland, Mobilunity is looking for a Backend Engineer (Python / FastAPI) (Node.js / Vue.js) - Part time

Our Client is an early-stage startup building a modular back-end platform for managing digital service workflows, combining payments, task execution, and verification into one scalable ecosystem.
At the core of the product is an escrow-like mechanism powered by Stripe, where funds are released based on predefined completion and verification conditions. Their broader vision is to create reusable, API-first infrastructure with independent modules such as payments, AI-based task completion, location verification, and image evidence handling.
They are looking for a strong Backend Engineer (Mid+ to Senior level) to take ownership of the MVP back-end architecture and implementation. This is a part-time / project-based opportunity for someone who enjoys building systems from the ground up, making technical decisions, and delivering production-ready back-end solutions.

The ideal candidate is someone who has experience building:

• Payment or fintech-related systems
• API-heavy backend applications
• Workflow/state machine-based systems
• Modular or service-oriented architectures

The role requires someone who is comfortable working independently, making architectural decisions, and delivering production-grade backend code in an MVP environment.

Requirements:

• Strong backend development experience in Python 3.12+
• Experience with FastAPI or similar modern Python web frameworks
• Proven experience designing and building RESTful APIs
• Strong understanding of system design and scalable backend architecture
• Experience with PostgreSQL (schema design, queries, migrations
• Strong experience integrating Stripe API (PaymentIntents, webhooks, refunds)
• Experience with authentication systems (JWT / OAuth2)
• Experience with Docker / Docker Compose
• Ability to implement unit and integration testing
• Strong English communication skills

Nice to have :

• Experience with SQLAlchemy / Alembic or similar ORM + migration tools
• Experience with S3-compatible storage (AWS S3, Cloudflare R2)
• Familiarity with AI integrations or external API orchestration
• Experience with event-driven or audit-logging architectures
• Exposure to geolocation or media upload systems
• Experience using or integrating MCP (Model Context Protocol)
• Experience in early-stage MVP / startup environments

In return we offer:

• The friendliest community of like-minded IT-people
• Open knowledge-sharing environment – exclusive access to a rich pool of colleagues willing to share their endless insights into the broadest variety of modern technologies
• Mobilunity Medical Insurance program designed to attend our teams’ needs
• Paid vacations and sick leaves, including 5 paid days per year that don’t require a sick note
• Perfect office location in the city-center (900m from Lukyanivska metro station with a green and spacious neighborhood) or remote mode engagement: you can choose a convenient one for you, with a possibility to fit together both
• No open-spaces setup – separate rooms for every team’s comfort and multiple lounge and gaming zones
• English classes in 1-to-1 & group modes with elements of gamification
• Neverending fun: sports events, tournaments, music band, multiple affinity groups

Come on board, and let’s grow together!