Understanding Flows

In Yuno SDKs, payment flows and enrollment flows are separate. Payment is the process of completing a transaction; enrollment is the process of saving a payment method (e.g. a card) to a customer account for future use. This page explains both flows at a high level with diagrams and step sequences. Use the Quickstart guide and platform flow pages for implementation details.

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Payment flow

The SDK provides a unified payment experience: customers complete transactions using multiple payment methods within a single integration. The diagram below illustrates the main payment workflow.

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Payment flow steps

1. Merchant Server: Create Customer → Yuno Server: Creates Customer
2. Merchant Client: Initiate Checkout → Merchant Server: Create Checkout session
3. Merchant Server: Create Checkout session → Yuno Server: Creates Checkout session
4. Merchant Client: Initiate Checkout → Initiate SDK to continue payment flow
5. Merchant Client: Initiate SDK to continue payment flow → Yuno SDK: Receive checkout session
6. Yuno SDK: Receive checkout session → List payment methods
7. Yuno SDK: List payment methods → User selects payment methods
8. Yuno SDK: User selects payment methods → Callback with the one-time token
9. Yuno SDK: Callback with the one-time token → Merchant Client: Receive one-time token (single use)
10. Merchant Client: Receive one-time token (single use) → Initiate payment
11. Merchant Client: Initiate payment → Initiate SDK to continue payment flow
12. Merchant Client: Initiate SDK to continue payment flow → Yuno SDK: Continue with the payment flow
13. Yuno SDK: Continue with the payment flow → Show screen for the user to complete payment
14. Yuno SDK: Show screen for the user to complete payment → Display payment result (optional)
15. Merchant Client: Initiate payment → Merchant Server: Create payment
16. Merchant Server: Create payment → Yuno Server: Creates payment in the payment provider

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Payment flow using a vaulted token

If a customer has an enrolled payment method, they can use a vaulted token to pay without entering payment details again.

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Vaulted token flow steps

1. Merchant Client: Initiate checkout → Merchant Server: Create Customer
2. Merchant Server: Create Customer → Yuno Server: Create Customer
3. Merchant Client: Initiate SDK with the checkout session → Yuno SDK: Receive checkout session
4. Yuno SDK: Receive checkout session → List payment methods
5. Yuno SDK: List payment methods → User selects payment methods
6. Yuno SDK: User selects payment method → Callback with the one-time token
7. Yuno SDK: Callback with the one-time token → Merchant Client: Initiate payment
8. Merchant Client: Initiate payment → Merchant Server: Create payment
9. Merchant Server: Create payment → Yuno Server: Creates payment in the payment provider
10. Merchant Client: Show payment result → Merchant Server: Receive payment result
11. Merchant Server: Receive payment result → Yuno Server: Provides payment result

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Enrollment flow

Enrollment is the process of saving a payment method (e.g. a card) to a customer’s account so it can be used later (e.g. with a vaulted token). full-checkout supports enrollment; the diagram below describes the enrollment workflow.

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Enrollment flow steps

1. Merchant Server: Create Customer → Yuno Server: Creates Customer
2. Merchant Client: Add payment method → Merchant Server: Create customer session
3. Merchant Server: Create customer session → Yuno Server: Creates customer session
4. Merchant Client: Display payment methods to enroll → Merchant Server: Request available payment methods to enroll
5. Merchant Server: Request available payment methods to enroll → Yuno Server: Returns available payment method
6. Merchant Client: Display payment methods to enroll → Merchant Client: User selects payment method to enroll
7. Merchant Client: User selects payment method to enroll → Merchant Client: Initiate enrollment
8. Merchant Client: Initiate enrollment → Merchant Client: Initiate SDK to continue enrollment
9. Merchant Client: Initiate SDK to continue enrollment → Yuno SDK: Continue enrollment flow
10. Yuno SDK: Continue enrollment flow → Yuno SDK: Shows screens for the user to complete enrollment
11. Merchant Server: Receive enrollment result via webhook → Yuno Server: Receive enrollment results from payment provider
12. Yuno Server: Receive enrollment results from payment provider → Yuno SDK: Display enrollment result (optional)

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Headless SDK flow

The Headless SDK provides maximum flexibility by allowing you to manage the entire user interface while Yuno handles the complex payment logic and security (like 3DS).

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Headless flow steps

1. Merchant Server: Create Customer → Yuno Server: Creates Customer
2. Merchant Client: Initiate Checkout → Merchant Server: Create Checkout session
3. Merchant Client: Collect Information → User enters card/payment details in your custom UI.
4. Merchant Client: Generate Token → Yuno SDK: Call generateToken(details) to receive a one-time token.
5. Merchant Client: Process Payment → Merchant Server: Send one-time token to your backend.
6. Merchant Server: Create Payment → Yuno Server: Call Create Payment API.
7. Merchant Client: Handle Actions → If API response returns sdk_action_required: true, use the SDK to handle 3DS or other Payment Actions.