Headless mode

Headless was a pure-tokenization client: the merchant collected card data in their own UI, generated a token, and made their own backend call to create the payment. In the unified API the same scenario is a headless start(). Pass the pre-collected data inside data on the paymentMethod you give to start(), override createPayment to POST to your backend (manual mode), and let the SDK orchestrate tokenization, 3DS, and status polling automatically. If you don’t want the SDK to continue the flow after creating the payment, set autoContinuePayment to false on the TransactionConfig object.

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 Headless you had	In the unified API	Session `workflow`
Your backend	Always: `generateToken`, then your own backend call	Override `createPayment`	Default (`SDK_CHECKOUT`)
The SDK	No equivalent: Headless never created the payment	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')

const apiClientPayment = await yuno.apiClientPayment({
    checkout_session: 'session-from-backend',
    country_code: 'CO',
})

// Merchant collects card data in their own UI, then:
const oneTimeToken = await apiClientPayment.generateToken({
    payment_method: {
        type: 'CARD',
        card: {
            detail: {
                holder_name: 'John Doe',
                number: '4111111111111111',
                security_code: '123',
                expiration_month: 12,
                expiration_year: 28,
            },
        },
        third_party_data: null,
    },
})

// Merchant POSTs to their backend
const paymentId = await myBackend.pay({ oneTimeToken, checkoutSession })

// If 3DS needed, merchant calls SDK again to challenge (bespoke per integration)

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

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

await transaction.start({
    paymentMethod: {
        type: 'CARD',
        data: {
            card: {
                holderName: 'John Doe',
                number: '4111111111111111',
                securityCode: '123',
                expirationMonth: 12,
                expirationYear: 28,
            },
        },
    },
})

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

Headless	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.
`checkout_session`, `country_code` arguments of `apiClientPayment`	`checkoutSession`, `countryCode` on the transaction config	Moved	Set them once in the config.
`holder_name`, `number`, `security_code`, `expiration_month`, `expiration_year` under `payment_method.card.detail` (argument of `generateToken`)	`holderName`, `number`, `securityCode`, `expirationMonth`, `expirationYear` under `paymentMethod.data.card`	Moved	Card data goes inline on `start()`, nested under `data.card`, in the unified `TransactionData` shape. That shape supports more fields to cover not only cards but also alternative payment methods (APMs) such as bank transfers, tickets, wallets, and more. See the full shape in `TransactionData`.
(none)	`paymentMethod.vaultedToken`	New	For vaulted cards, pass `vaultedToken` on `paymentMethod` and only `securityCode` under `data.card`: `transaction.start({ paymentMethod: { type: 'CARD', vaultedToken: 'tok_saved_abc', data: { card: { securityCode: '123' } } } })`.

Callbacks

Headless	Unified	Change	What to do
Your own backend call after `generateToken`	`createPayment(token)`	Moved	Wire it on the transaction config: `token` is the same token `generateToken` used to return directly to your code, now delivered as the argument of your override; there’s no separate call to fetch it. POST it to your backend and resolve the Promise: the SDK continues from there. See `createPayment` and `OneTimeToken`.
(no result callback)	`onStatus(result)`	New	The SDK now drives the full lifecycle (tokenization, 3DS, status polling) and reports the final status here. See `Status`.

Entry points

Headless	Unified	Change	What to do
`yuno.apiClientPayment({ checkout_session, country_code })`	`sdkPayments.transaction({ checkoutSession, countryCode, createPayment })`	Renamed	The factory consolidates the API-client and Transaction surfaces: no separate `apiClientPayment` surface, one `sdkPayments.transaction(config)`.
`apiClientPayment.generateToken(cardData)`	`transaction.start({ paymentMethod: { type: 'CARD', data: { card } } })`	Renamed	You no longer tokenize yourself: build the `paymentMethod` with your pre-collected card data (see Initialization and config), then `start`. The SDK tokenizes and calls `createPayment` with the token.
`apiClientPayment.getThreeDSecureChallenge(...)` (rare)	(removed)	Removed	Delete the call. Headless used to require bespoke 3DS handling per integration; the SDK orchestrates 3DS internally once `createPayment` resolves.
`yuno.continuePayment()` after backend POST	(removed)	Removed	Delete the call: the Promise contract drives progression. Resolve `createPayment` and the SDK continues.

createPayment. The mode-flip callback.
TransactionData. Per-method headless data shape.
OneTimeToken. Token payload sent to your backend.

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