Build the Drop
Dropshipping SaaS that connects AliExpress with Shopify: it imports products, syncs stock and prices, and places and pays orders automatically.
- Type
- Dropshipping SaaS
- Backend
- NestJS on Lambda + API Gateway
- Events
- SQS and EventBridge
- Data
- MongoDB
- Billing
- Stripe
Design decisions
Nothing heavy inside the request
The API authenticates with Cognito, validates and enqueues. Every event (order created, stock change, Stripe webhook) goes into SQS and is processed by its own handler.
One queue per event type
It absorbs spikes, allows retries and isolates each flow’s failures. An EventBridge cron triggers the stock sync.
Three frontends, one backend
React dashboard with TanStack Router and Query, embedded Shopify app with Polaris and a public Astro site, all against the same API.
Infrastructure as code
The whole AWS deployment lives in CDK; Bedrock generates product content and Stripe handles subscriptions.
- NestJS
- AWS Lambda
- SQS
- CDK
- React
- MongoDB
- Shopify API
- Stripe
Architecture
Go deeper
- Anatomy of a serverless SaaS on AWS
The architecture of Build the Drop: bulk syncing between marketplaces with functions, queues and a small budget.
- Designing a payment system that never charges twice
Idempotency, states and reconciliation: the diagram of a checkout flow with several providers.