Seamless mode

Seamless mode was the SDK-managed variant: the SDK created the payment internally, the merchant only chose when/where to render the form and triggered the start via yuno.startPayment(). Unlike non-Seamless mode, Seamless did not expose yunoCreatePayment: payment creation was always managed by the SDK. In the unified API the same flow is a normal Transaction without createPayment wired (presence of createPayment flips to manual mode; its absence stays managed). Your Pay button calls transaction.start({ paymentMethod }) with the method the user picked in the list.

Before you start

Load the unified SDK bundle instead of the legacy one and initialize it as the side-by-side shows: window.Yuno.initialize(...) becomes SdkPayments.initialize(...). Your public API key and the checkout sessions your backend creates do not change (Before you begin).
Decide who creates the payment. The checkout session’s workflow must match that decision:

Who creates the payment	In Seamless you had	In the unified API	Session `workflow`
Your backend	No equivalent: Seamless never let you create it	Override `createPayment`	Default (`SDK_CHECKOUT`)
The SDK	Always	No override	`SDK_SEAMLESS`

A default-workflow session with no createPayment override ends in INTERNAL_ERROR: the backend rejects the SDK’s payment creation. See createPayment.

Side-by-side

Seamless Full

const yuno = await window.Yuno.initialize('your-public-api-key')

await yuno.startSeamlessCheckout({
    checkoutSession: 'session-from-backend',
    elementSelector: '#root',
    countryCode: 'CO',
    language: 'en',
    yunoPaymentResult: (status) => console.log('done:', status),
})

await yuno.mountSeamlessCheckout()

// Merchant's pay button triggers. SDK does everything else
document.getElementById('pay').addEventListener('click', () => {
    yuno.startPayment()
})

const sdkPayments = await SdkPayments.initialize('your-public-api-key')

const transaction = sdkPayments.transaction({
    checkoutSession: 'session-from-backend',
    countryCode: 'CO',
    language: 'en',
    elementSelector: '#payment-form', // form container for the selected method (form flows only)
    // managed mode: no createPayment wired
    onStatus: (result) => console.log('done:', result.status),
})

let selectedPaymentMethod: PaymentMethodSelected | null = null

const views = transaction.getPaymentMethodsViews({
    types: ['paymentMethodList'],
    onPaymentSelected: (paymentMethod) => {
        selectedPaymentMethod = paymentMethod
    },
})

views.paymentMethodList?.mount({ elementSelector: '#root' })

// Your Pay button. With forms unfolded in the list, start() submits the form the shopper filled.
// With folded forms, start() mounts the form into #payment-form and the shopper pays from it.
document.getElementById('pay').addEventListener('click', () => {
    if (selectedPaymentMethod) transaction.start({ paymentMethod: selectedPaymentMethod })
})

Seamless External Buttons

const yuno = await window.Yuno.initialize('your-public-api-key')

await yuno.startSeamlessCheckout({
    checkoutSession: 'session-from-backend',
    countryCode: 'CO',
    yunoPaymentResult: (status) => console.log('done:', status),
})

yuno.mountSeamlessExternalButtons([
    { elementSelector: '#apple-pay', paymentMethodType: 'APPLE_PAY' },
    { elementSelector: '#google-pay', paymentMethodType: 'GOOGLE_PAY' },
    { elementSelector: '#paypal', paymentMethodType: 'PAYPAL' },
])

const sdkPayments = await SdkPayments.initialize('your-public-api-key')

const transaction = sdkPayments.transaction({
    checkoutSession: 'session-from-backend',
    countryCode: 'CO',
    onStatus: (result) => console.log('done:', result.status),
})

// Tapping a wallet button pays. No start() call needed
const views = transaction.getPaymentMethodsViews({
    types: ['applePay', 'googlePay', 'paypal'],
})

views.applePay?.mount({ elementSelector: '#apple-pay' })
views.googlePay?.mount({ elementSelector: '#google-pay' })
views.paypal?.mount({ elementSelector: '#paypal' })

What changes

Grouped in the order you edit the code. Renamed: same role, new name. Moved: same value, new owner. Removed: nothing to call. New: no legacy counterpart. The last column is the only thing you have to do beyond the rename.

Initialization and config

Seamless	Unified	Change	What to do
`window.Yuno.initialize(publicApiKey)`	`SdkPayments.initialize(publicApiKey)`	Renamed	The global is `window.SdkPayments`. As before, `await` it: it resolves to the `SdkPayments` instance you create transactions from.
`checkoutSession`, `countryCode`, `language` on the `startSeamlessCheckout` config	The same fields on the transaction config	Moved	Same values, single factory.
`elementSelector` on the `startSeamlessCheckout` config	`elementSelector` on the transaction config	Moved	Required when `start({ paymentMethod })` renders a form. The form renders inside this element, and the SDK throws without it. Headless flows ignore it. The list and wallet views keep their own `elementSelector` on `.mount()` (see Views).

Callbacks

Seamless	Unified	Change	What to do
`yunoPaymentResult(status, subStatus?)`	`onStatus(result)`	Renamed	Still the single outcome callback, now a field on the transaction config. It receives one `TransactionStatus` object (`status`, `substatus`, `message`). See `Status`.
(none)	`onPaymentSelected(paymentMethod)` inside `getPaymentMethodsViews`	New	Optional. With the list, store the method it delivers and pass it to `transaction.start({ paymentMethod })` from your Pay button (see Entry points). Wallet buttons do not need it. The tap is the confirmation, and the SDK starts the payment itself and reports through `onStatus`.
(none: payment creation was always managed)	`createPayment`	New	Don’t wire it. Its presence flips to manual mode (non-Seamless behavior); its absence keeps the SDK in managed mode, the same model Seamless had.

Views

Seamless	Unified	Change	What to do
`yuno.mountSeamlessCheckout()`	`getPaymentMethodsViews({ types: ['paymentMethodList'], onPaymentSelected })`, then `views.paymentMethodList?.mount({ elementSelector })`	Renamed	Get a view handle, then call `.mount(...)` with the selector. See Payment Methods List.
`yuno.mountSeamlessExternalButtons([{ elementSelector, paymentMethodType }])`	`getPaymentMethodsViews({ types: ['applePay', 'googlePay', 'paypal', 'paypalBraintree', 'revolutPay', 'samsungPay'] })`, then `views.applePay?.mount({ elementSelector, ...config })`, etc.	Renamed	One `.mount()` per wallet button. Map each v1 `paymentMethodType` to its view key: `APPLE_PAY` to `applePay`, `GOOGLE_PAY` to `googlePay`, `PAYPAL` to `paypal`, `PAYPAL_BRAINTREE` to `paypalBraintree`, `REVOLUT_PAY` to `revolutPay`, `SAMSUNG_PAY` to `samsungPay`. Per-view styling (button color, type, etc.) lives on each `.mount()` call.
`yuno.unmountSeamlessExternalButton(type)` / `yuno.unmountSeamlessExternalButtons()`	(removed)	Removed	Per-button unmount removed. `transaction.unmount()` removes the form the transaction mounted and reports `USER_CANCEL` through `onStatus` when no result was delivered yet. The wallet buttons stay on the page until you remove their containers.

Entry points

Seamless	Unified	Change	What to do
`yuno.startSeamlessCheckout(config)`	`sdkPayments.transaction(config)`	Renamed	The `Seamless` factory is gone: use the regular factory, without `createPayment` (see Callbacks).
`yuno.startPayment()` (merchant trigger)	`transaction.start({ paymentMethod })` with the list, `transaction.submit()` with a form that `start()` mounted	Renamed	With the list, your Pay button calls `start({ paymentMethod })` with the method the user picked. It submits the form the list opened inline. With a pre-selected method, `start({ paymentMethod })` mounts the form into the config’s `elementSelector` and your Pay button calls `submit()` (set `showPayButton: false`). Wallet buttons pay on tap and need neither.

Payment Methods List. getPaymentMethodsViews reference.
TransactionConfig. Complete field reference.
Lite mode. For non-Seamless integrations using yunoCreatePayment (manual mode).

Start here

Guides

Listen and take over

API reference

Upgrade from older SDKs

Before you start

Side-by-side

Seamless Full

Seamless External Buttons

What changes

Initialization and config

Callbacks

Views

Entry points

​Before you start

​Side-by-side

​Seamless Full

​Seamless External Buttons

​What changes

​Initialization and config

​Callbacks

​Views

​Entry points

​Related

Before you start

Side-by-side

Seamless Full

Seamless External Buttons

What changes

Initialization and config

Callbacks

Views

Entry points

Related