Shopify Custom App Developer – LegitApp API + Webhook Integration
Budget: ₹12,500 – ₹37,500 INR
We are looking for an experienced Shopify developer to build a small custom backend app (not theme editing) to integrate our Shopify store with an external authentication service API (LegitApp).
This is a glue/automation project — the external service already handles all UI and workflows. We only need backend integration.
Customer Flow
Customer purchases an “Authentication Service” product on Shopify (category-based pricing)
After order is paid, our backend should:
Call external API to create an authentication intent
Receive a hosted submission URL
Save intent ID, submission URL, and status to Shopify order metafields
Email customer with submission link
Customer completes submission on the external hosted page (photos etc handled externally)
External service sends webhook events to our backend:
initial submission received
extra photos required
extra photos submitted
authentication completed
On each webhook event, backend should:
Update Shopify order metafields (status, result, certificate link)
Send customer email notifications
Customer can view authentication status and certificate inside Shopify order history.
Required Technical Work
Build Shopify custom app or secure backend service
Shopify webhooks: orders/paid
External REST API integration (Bearer auth)
External webhooks receiver + processing
Store data in Shopify order metafields
Email sending integration (SendGrid, Klaviyo, or similar)
Order page UI block showing status + buttons
What is NOT required
No front-end upload UI
No brand/model selector UI
No certificate system
(All handled by external service)
Skills Required
Shopify custom app development
Webhooks (Shopify + external service)
REST API integration
Shopify metafields
Email API integration
Deliverables
Fully automated Shopify → API → Webhook workflow
Clean documented code
Basic setup instructions
Estimated Scope
Small integration project (not full platform build)
Optional question
“Have you built Shopify custom apps using webhooks and external APIs before? Please share example.”
This is a glue/automation project — the external service already handles all UI and workflows. We only need backend integration.
Customer Flow
Customer purchases an “Authentication Service” product on Shopify (category-based pricing)
After order is paid, our backend should:
Call external API to create an authentication intent
Receive a hosted submission URL
Save intent ID, submission URL, and status to Shopify order metafields
Email customer with submission link
Customer completes submission on the external hosted page (photos etc handled externally)
External service sends webhook events to our backend:
initial submission received
extra photos required
extra photos submitted
authentication completed
On each webhook event, backend should:
Update Shopify order metafields (status, result, certificate link)
Send customer email notifications
Customer can view authentication status and certificate inside Shopify order history.
Required Technical Work
Build Shopify custom app or secure backend service
Shopify webhooks: orders/paid
External REST API integration (Bearer auth)
External webhooks receiver + processing
Store data in Shopify order metafields
Email sending integration (SendGrid, Klaviyo, or similar)
Order page UI block showing status + buttons
What is NOT required
No front-end upload UI
No brand/model selector UI
No certificate system
(All handled by external service)
Skills Required
Shopify custom app development
Webhooks (Shopify + external service)
REST API integration
Shopify metafields
Email API integration
Deliverables
Fully automated Shopify → API → Webhook workflow
Clean documented code
Basic setup instructions
Estimated Scope
Small integration project (not full platform build)
Optional question
“Have you built Shopify custom apps using webhooks and external APIs before? Please share example.”