Understanding the Flow

Below is a step-by-step explanation of each operation pertaining to the Integration Architecture

Step	Operation	Type	Explanation
Step 1	Prefetch	SDK call (Merchant App -> Payments SDK)	Prefetch all the latest SDK updates. It is recommended to call prefetch from your App’s homescreen.
Step 2	Fetch Signed Payload Token	API call (Merchant App -> Merchant Server)	Merchant App shall fetch a signed payload from Merchant Server. This signed session token is required to perform Step 3 (Initiate).
Step 3	Initiate	SDK call (Merchant App -> Payments SDK)	Merchant App shall initiate the SDK with signed payload of customer details. This operation will start Juspay Payments SDK in the background. It is highly recommended to call initiate SDK from the order summary page (atleast 5 seconds before starting the payment page) for a seamless user experience. This is to optimize background API calls to find / create customer, refresh wallet balances and fetch enabled payment methods.
Step 4	Fetch Signed Order details	API call (Merchant App -> Merchant Server)	Merchant App shall fetch signed order details from Merchant Server. This signed session token is required to perform Step 5 (Process).
Step 5	Process	SDK call (Merchant App -> Payments SDK)	This operation shall open the Payment page for the user.
Step 6	Handle SDK events	SDK response handling	The SDK shall pass all events back to the Merchant’s App using callbacks.
Step 7	Terminate	SDK call (Merchant App -> Payments SDK)	Merchant App shall terminate the Payments SDK. It is an optional call which may be done by a merchant to free up memory once Payments SDK is no longer used.
Step 9	Webhooks	Webhook (Juspay Server -> Merchant Server)	After the completion of every payment/refund call, Juspay will provide direct notification to your server regarding the event. These are called Webhooks. You must configure a valid HTTP endpoint that is reachable from our servers to consume these notifications. Our servers will push data using HTTP POST call to your endpoint. Reference: https://developer.juspay.in/docs/integration#section-webhooks
Step 10	Check Order Status / Refund Statu	S2S API call (Merchant Server -> Juspay Server)	Fetch the order status/ refund status from Juspay Server, post completion of user transaction. Reference: https://developer.juspay.in/reference#get-order-status
Step 11	Initiate Refund	S2S API call (Merchant Server -> Juspay Server)	Initiate refund against any successful order via Juspay Server. Reference: https://developer.juspay.in/reference#refund-order