Python FastAPI Developer Needed for SMM Provider API Integration

We already have a working SMM panel built with Python FastAPI and PostgreSQL.

We need an experienced backend developer to build or integrate a separate delivery/provider API module into our existing system.

Required functionality:

Create delivery orders using target, service type and quantity
Return a unique order ID
Order status: pending, processing, completed, partial, failed, cancelled
Return delivered and remaining quantity
Inventory/capacity endpoint for Premium and Standard services
API key or Bearer token authentication
Idempotency protection to prevent duplicate orders
Proper JSON error responses
Optional cancel endpoint
Webhook support is preferred
API documentation and test access must be provided

Our existing frontend, admin panel, users, balances, orders, PostgreSQL database and FastAPI backend are already built. We do NOT need the whole website rebuilt.

Deliverables:

Working API/module
API documentation
Test credentials/access
Example requests/responses
Deployment instructions

Please apply only if you have strong experience with Python, FastAPI, REST APIs, PostgreSQL, asynchronous workers/queues and third-party API integrations.