Telecom

SimStack

A FastAPI-powered eSIM provisioning platform that fully automates order-to-activation flow — from Stripe payment collection to async eSIM resource allocation via third-party APIs.

The Challenge

The MVNO relied on manual order processing and fragmented payment handling. Each eSIM activation required staff to verify payment, provision the eSIM through a third-party dashboard, and email credentials to the customer — taking up to 24 hours. Scaling to higher order volumes was impossible without a fully automated pipeline.

The Solution

We built SimStack, a FastAPI backend that orchestrates the entire lifecycle: Stripe PaymentIntent creation at order placement, idempotent webhook handling for payment confirmation, background task queues for eSIM package purchasing, and async webhook reception for eSIM resource allocation. The system polls the eSIM Access API for order status and automatically creates eSIM records once resources are allocated.

Key Features

Stripe PaymentIntent integration with idempotent webhook handling
Async background task queue for eSIM package purchasing
eSIM Access API integration (purchase, query, status polling)
Webhook receiver for async eSIM resource allocation notifications
Automatic order status transitions (PENDING → PAID → ACTIVE)
Comprehensive logging and error recovery for failed activations

Technologies

FastAPIPythonPostgreSQLStripeRedisCeleryDockerSQLAlchemyAlembic

Results

End-to-end eSIM activation in under 60 seconds

Eliminated manual order processing entirely

Zero failed activations due to payment verification gaps

Scalable architecture ready for high-volume MVNO growth

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