Seamless Lite mode

Seamless Lite combined two legacy traits: Seamless (the SDK created the payment internally, with no yunoCreatePayment callback exposed) and Lite (the payment method was pre-selected by the merchant; the SDK only rendered the form for that one method). In the unified API transaction.start({ paymentMethod }) mounts the form for the pre-selected method and transaction.submit() pays from your button. No createPayment on the config (Seamless was always managed).

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 Lite 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

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.mountSeamlessCheckoutLite({
    paymentMethodType: 'PIX',
    vaultedToken: null,
})

// 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: '#root',
    showPayButton: false,
    // managed mode: no createPayment wired
    onStatus: (result) => console.log('done:', result.status),
})

// Mount the form for the pre-selected method
await transaction.start({
    paymentMethod: { type: 'PIX' },
})

// Merchant's pay button submits it. SDK does everything else
document.getElementById('pay').addEventListener('click', () => {
    transaction.submit()
})

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 Lite	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. `start({ paymentMethod })` renders the form inside that element and throws without it. Headless flows ignore it.
`showPayButton` on the `startSeamlessCheckout` config	`showPayButton` on the transaction config	Moved	Same meaning. Payment flows only.

Callbacks

Seamless Lite	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`.
`yunoError(message, data?)`	(removed)	Removed	Errors flow through `onStatus`, or a rejected `start()` Promise.
`onLoading({ isLoading, type })`	`showLoading(isLoading)`	Renamed	Optional. Boolean signal only. See `showLoading`.
(none: payment creation was always managed)	`createPayment`	New	Don’t wire it. Its absence keeps the SDK in managed mode, the same model Seamless had.

Entry points

Seamless Lite	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.mountSeamlessCheckoutLite({ paymentMethodType, vaultedToken })` + `yuno.startPayment()` (merchant trigger)	`transaction.start({ paymentMethod: { type, vaultedToken } })` + `transaction.submit()`	Renamed	Same two steps. `start()` mounts the form inside the `elementSelector` set on the transaction config, and the pre-selection becomes its `paymentMethod` argument. `submit()` is your pay trigger. Set `showPayButton: false` to hide the SDK’s button. `Lite` vs `Full` is gone as a method split: it’s now whether you pass `paymentMethod` to `start()` directly (pre-selected) or get it from `onPaymentSelected` inside `getPaymentMethodsViews` (user picks from the list).
`yuno.submitOneTimeTokenForm()`	`transaction.submit()`	Renamed	Submits the form `start()` mounted, from your own button. Use it with `showPayButton: false`. See Web: submit from your own button.

TransactionConfig. Complete field reference.
Seamless mode. For Seamless Full and Seamless External Buttons.
Lite mode. For non-Seamless Lite (which supports yunoCreatePayment for manual mode).

Start here

Guides

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API reference

Upgrade from older SDKs

Before you start

Side-by-side

What changes

Initialization and config

Callbacks

Entry points

​Before you start

​Side-by-side

​What changes

​Initialization and config

​Callbacks

​Entry points

​Related

Before you start

Side-by-side

What changes

Initialization and config

Callbacks

Entry points

Related