Validator: Web SDK v1 to v2 migration - Yuno API Documentation

Drop this file in the root of your project and ask your coding agent:

List what I must change to move my Yuno Web SDK integration to v2, following this file.

It works as CLAUDE.md, AGENTS.md or a pasted prompt, with Claude Code, Cursor, Codex or Copilot. It is read-only: it scans your code and reports, and it changes nothing unless you ask. The target. v2 is the sdk-web 2.x line (“Yuno SDK 2.x”, the unified Transaction API). The latest release is version 2.2.0 (2026-10-27). It is served at https://sdk-web.y.uno/v2.2.0/main.js, and v2.0.0, v2.1.0, v2.1.2 are also live. There is no rolling folder: /v2/, /v2.0/ and /v2.2/ return 404, so you pin a full version and bump it by hand. The EU host sdk-web.prod.eu.y.uno serves up to v2.1.2 and returns 404 for v2.2.0 (at the time of writing). The SRI path is https://prod.y.uno/sdk-static-bundles-ms/sdk-web/v2.2.0/main.js. Public docs: the “SDK” tab (docs/yuno-sdk/*, migration series in docs/yuno-sdk/migration/web/*). The “SDKs” tab is the 1.x line. v1.x stays supported side by side until 2027. The source. v1.11 (window.Yuno, rolling /v1.11/main.js), the current 1.x line.

v1.11                                              v2
<script .../v1.11/main.js>                         <script .../v2.2.0/main.js>
yuno = await Yuno.initialize(key)                  sdk = await SdkPayments.initialize(key)
yuno.startCheckout(cfg)        (or Seamless)       tx = sdk.transaction(cfg)   (session, country, onStatus,
yuno.mountCheckoutLite({...})                           createPayment present = manual, absent = managed)
yuno.mountCheckout()                               tx.start({ paymentMethod })          form or headless
yunoCreatePayment(ott, info, cs)                   tx.getPaymentMethodsViews({...}).paymentMethodList.mount()
yuno.continuePayment()                             createPayment(token)  -> SDK continues by itself
yunoPaymentResult(status) / yunoError(...)         onStatus({ status, substatus, message })
yuno.unmountSdk()                                  await tx.unmount()

What v2 keeps (do not report these as blocking)

v2 keeps no v1 alias. It sets only window.SdkPayments and dispatches only sdk-payments-ready. It does not set window.Yuno and never fires yuno-sdk-ready. Every window.Yuno and yuno-sdk-ready use must change.
v1.11 already exposes the v2 names. It sets both globals and fires both events. So window.SdkPayments and sdk-payments-ready in a v1.11 repo are already correct. That rename can ship on 1.11 first, before the script switch.
Unchanged on v2: the sdk-payments-* CSS prefix; the initialize options keys (cookies, sdkType, apiUrl, assetUrl, plugin); clearApiCache() and setCanaryMode() on the instance; onChange(state); the options onPromotionQuoteUpdated, externalButtons, texts, issuersFormEnable, showPayButton, deviceFingerprints, paymentListConfig, savePaymentMethodEnabled; the card keys styles, type (except 'step'), vaultOnSuccess, texts, documentEnable, isCreditCardProcessingOnly, fonts, onChange, onGetInstallments, onInstallmentSelected.
Silent keys. v2 forwards unknown or v1-only config keys without any error. Most are never read: the feature they controlled just disappears. Mark those rows SILENT. Three v1 keys are still read on 2.2.0: onLoading is still called when no showLoading function is set; paymentMethodSelected and yunoPaymentMethodSelected still fire on every list selection, so keeping one next to onPaymentSelected gives two calls per selection; yunoCreatePayment is merged into createPayment in state. Rename them anyway.
CSS. v2 renders yuno-container-spinner-content and yuno-container-spinner-ring (the loading spinner of every mount) and sets data-yuno-placeholder. These are v2 names: never report selectors on them.

How to use

Find the v1 surface. Run over source, server templates, tag-manager snippets and package.json:

grep -rnE "window\.Yuno\b|\bYuno\.initialize|yuno-sdk-ready|YunoSDK|sdk-web\.[a-z.]*y\.uno/v[0-9.]+/main\.js|sdk-static-bundles-ms/sdk-web/|loadScript\(|@yuno-payments/sdk-web(-types)?" --exclude-dir=node_modules --exclude-dir=.git --exclude-dir=dist --exclude-dir=build .
grep -rnE "\.(startCheckout|startSeamlessCheckout|mountCheckout|mountCheckoutLite|mountSeamlessCheckout|mountSeamlessCheckoutLite|mountSeamlessExternalButtons|mountExternalButtons|unmountExternalButton|unmountAllExternalButtons|unmountSeamlessExternalButtons?|mountEnrollmentLite|mountFraud|mountStatusPayment|startPayment|continuePayment|submitOneTimeTokenForm|unmountSdk|showLoader|hideLoader|notifyError|apiClientPayment|apiClientEnroll|continueEnrollment|clickToPay|executeFraudCheck|generateToken\w*|getThreeDSecureChallenge|getContinuePaymentAction|isPaymentMethodAvailable|updateCheckoutSession|refreshPromotionQuote)\(" --exclude-dir=node_modules --exclude-dir=.git --exclude-dir=dist --exclude-dir=build .
grep -rnE "yunoPaymentResult|paymentResult|yunoError|yunoEnrollmentStatus|enrollmentStatus|yunoCreatePayment|createPayment|yunoPaymentMethodSelected|paymentMethodSelected|onLoading|showLoading|showPaymentStatus|renderMode|viewContainer|onlyExpressPaymentMethods|stickyPayButton|__internal|cardSaveEnable|requiredFieldsOrderedEnabled|topLevelDomain|isRetrying|newCheckoutSession|payment_method\.card\.detail|holder_name|enableV2|enableMultiplesCard|\.render\(" --exclude-dir=node_modules --exclude-dir=.git --exclude-dir=dist --exclude-dir=build .
grep -rnE "'(FAIL|REJECT|PROCESSING|READY)'|\"(FAIL|REJECT|PROCESSING|READY)\"|type:\s*['\"]step['\"]|checkout/sessions|workflow" --exclude-dir=node_modules --exclude-dir=.git --exclude-dir=dist --exclude-dir=build .

Find any v2 surface already present: grep -rnE "SdkPayments\.initialize|\.transaction\(|\.start\(\{|getPaymentMethodsViews|transactionStatus|\.antifraud\(|onStatus|saveCardEnabled|showStatusScreen|sdk-web\.[a-z.]*y\.uno/v2". A repo with both is mid-migration: report the v1 leftovers on every page that loads the v2 script. At runtime, typeof sdk.transaction === 'function' means v2; a v1 instance has startCheckout and no transaction.
Classify each flow (Lite, Full, Seamless, Seamless Lite, external buttons, headless, Secure Fields, enrollment, fraud, status screen) as manual (merchant creates the payment) or managed (SDK creates it).
Map every hit with the table below, run checks M1 to M25, and write the report.

Mapping

Sections follow the research table 3.A to 3.H. Kind: KEEP, RENAME, MOVE, BEHAVIOUR, NEW REQUIRED, REMOVED (no replacement), SILENT (v2 accepts and ignores the old key), BLOCKED (parity gap: report “blocked: parity gap, do not migrate this flow yet”, not as a change).

3.A Bootstrap and globals

v1.11	v2	Kind	What to do	Evidence
`window.Yuno`, `new Yuno`, `YunoSDK`	`window.SdkPayments`	RENAME	Replace every reference	`src/main.ts` on 1.11 vs 2.2.0
`yuno-sdk-ready` event	`sdk-payments-ready`	RENAME	Listen to the new event; also check `window.SdkPayments` first	same
`<script .../v1.11/main.js>`	`<script .../v2.x.y/main.js>`	BEHAVIOUR	Pin a full version; no rolling folder	CDN probes at the time of writing
npm `loadScript()`	`loadScript({ baseUrl: 'https://sdk-web.y.uno/v2.x.y' })`	BEHAVIOUR	Pass `baseUrl`; drop `sri: true` (its URL and hashes are fixed to v1.11)	npm loader `get-url.ts`, `inject-script.ts`
`@yuno-payments/sdk-web-types`	none published	REMOVED	Write a local declaration from the public v2 migration pages	`@yuno-payments/sdk-web-types` declares `startCheckout`, no `transaction`
`await Yuno.initialize(key, appSession?, opts?)`	`await SdkPayments.initialize(...)`	RENAME + BEHAVIOUR	Same args; same args return the same instance, new args supersede the old one	`sdk-payments.ts`

3.B Entry points and flow modes

v1.11	v2	Kind	What to do	Evidence
`startCheckout(cfg)` + `mountCheckoutLite({paymentMethodType, vaultedToken})`	`sdk.transaction(cfg)` + `tx.start({paymentMethod:{type, vaultedToken}})`	RENAME	Move config to `transaction()`	docs `migration/web/lite`
`startCheckout(cfg)` + `mountCheckout()`	`transaction(cfg)` + `getPaymentMethodsViews({types:['paymentMethodList'], onPaymentSelected})` + `views.paymentMethodList.mount({elementSelector})`	RENAME + NEW REQUIRED	Your Pay button calls `tx.start({paymentMethod: selected})`	docs `full`
`startSeamlessCheckout` + `mountSeamlessCheckout()` + `startPayment()`	Full flow without `createPayment`; `startPayment()` becomes `start({paymentMethod})`	RENAME	Keep `workflow: SDK_SEAMLESS`	docs `seamless`
`startSeamlessCheckout` + `mountSeamlessCheckoutLite` + `startPayment()`	`transaction({...showPayButton:false})` + `start({paymentMethod})` + `tx.submit()`	RENAME		docs `seamless-lite`
`mountSeamlessExternalButtons([{elementSelector, paymentMethodType}])`	`getPaymentMethodsViews({types:[wallets]})` + `views.<wallet>.mount({elementSelector})`	RENAME	Keys `applePay googlePay samsungPay paypal paypalBraintree revolutPay`	docs `seamless`
`apiClientPayment(...).generateToken(card)` + backend call + `continuePayment()`	`start({paymentMethod:{type:'CARD', data:{card}}})` with `createPayment`	RENAME		docs `headless`
`getThreeDSecureChallenge`, `getContinuePaymentAction`, `generateHeadlessToken`	none (3DS is internal)	REMOVED	Delete custom 3DS code	docs `headless`
`secureFields(args)`	`await tx.secureFields({installmentEnable?})`	MOVE	Session, country, language, fingerprints go to `transaction()`; drop `enableV2`, `enableMultiplesCard`	docs `secure-fields`
`mountEnrollmentLite({customerSession,...})`	`transaction({customerSession,...}).start()`	RENAME		docs `enrollment`
`apiClientEnroll(...).continueEnrollment(...)`	`transaction({customerSession}).start({paymentMethod:{type, data}})`	RENAME		docs `enrollment`
`mountStatusPayment({checkoutSession, language, countryCode})`	`await sdk.transactionStatus({checkoutSession, elementSelector, ...})`	RENAME + NEW REQUIRED	`elementSelector` is now required	docs `status`
`executeFraudCheck(args)`	`await sdk.antifraud(args)`	RENAME + BEHAVIOUR	Never rejects; branch on `result.status`	docs `fraud`
`mountFraud({checkoutSession, language, type, yunoCreatePayment, ...})`: a card UI that creates the payment	`sdk.transaction({checkoutSession, countryCode, deviceFingerprints?, createPayment?, onStatus})` + `tx.start({paymentMethod:{type:'CARD'}})`	RENAME + BEHAVIOUR	Do not delete: it is a payment flow. `yunoCreatePayment(ott, info)` becomes `createPayment(token)`; `yunoError` goes to `onStatus`. The repo’s `docs/NEW_PUBLIC_API.md` row 16 maps it to `sdk.antifraud` and disagrees; follow the public page	v1 `sdk/fraud/mount-fraud.ts`; docs `migration/web/fraud.mdx`
`submitOneTimeTokenForm()`	`tx.submit()`	RENAME	Only after `start()` resolved	docs `lite`
`unmountSdk()`	`await tx.unmount()`	RENAME + BEHAVIOUR	Async; may deliver `USER_CANCEL`; wallets stay	`transaction.ts`
`updateCheckoutSession(cs)`	`tx.updateCheckoutSession(cs)`	MOVE	Payment only	SDK source
`isPaymentMethodAvailable({paymentMethodType, checkoutSession?})`	`tx.isPaymentMethodAvailable({paymentMethodType})`	MOVE	Session comes from the config	SDK source
`refreshPromotionQuote()`	`tx.refreshPromotionQuote()`	MOVE	@alpha, inert today	SDK source
`continuePayment(options?)`	none	REMOVED	Delete; the SDK continues after `createPayment` resolves	docs `lite`
`notifyError()`	reject the `createPayment` promise	RENAME	Listed as a v1-only feature, but rejection covers it	SDK source

3.C Option and callback names

v1.11	v2	Kind	What to do	Evidence
`yunoPaymentResult` / `paymentResult(status, subStatus, details)`	`onStatus({status, substatus, message})`	RENAME + SILENT	Old key is ignored: no result ever arrives	docs `lite`
statuses `'FAIL' 'REJECT' 'PROCESSING' 'READY'`	backend statuses + `INTERNAL_ERROR` + `USER_CANCEL`	BEHAVIOUR	Rewrite every comparison	v1 SDK source
`details.isRetrying`, `details.newCheckoutSession`	`token.checkout_session` in `createPayment`	REMOVED		docs `create-payment`
`yunoError` / `error(message, data)`	`onStatus` `INTERNAL_ERROR` or a rejected `start()`	REMOVED + SILENT		v2 has no read of `yunoError`
`yunoEnrollmentStatus` / `enrollmentStatus({status, vaultedToken})`	`onStatus`; no `vaultedToken`	RENAME + BEHAVIOUR	Fetch the vaulted token server-side	docs `enrollment`
`yunoCreatePayment` / `createPayment(ott, info, checkoutSession)`	`createPayment(token)`, returns a Promise	RENAME + BEHAVIOUR	`token.token` = old `ott`; `token.checkout_session` = old third arg. A lone `yunoCreatePayment` is merged into `createPayment`, but rename it	core `types/handlers.ts` `CreatePaymentCallback`; `lib/callback-aliases.ts`
`yunoPaymentMethodSelected` / `paymentMethodSelected({type,name})`	`onPaymentSelected` in `getPaymentMethodsViews`	RENAME + BEHAVIOUR	Store it and pass it to `start()`. Remove the old key: it still fires on list selections, so both give two calls	docs `full`; SDK source
`onLoading({isLoading, type})`	`showLoading(isLoading)`	RENAME	Not silent: v2 still calls `onLoading` when no `showLoading` function is set. Move to `showLoading`, which replaces the SDK loader	docs `show-loading`; SDK source
`showLoading: true/false`	`showLoading` must be a function	BEHAVIOUR	`true` throws a TypeError that names a minified function, not `showLoading`; `false` is treated as no handler and silently brings back the SDK loader	SDK source
`showPaymentStatus`	`showStatusScreen`	RENAME + SILENT		v2 SDK source
`elementSelector` on `startCheckout`	on `transaction()`, `string \| HTMLElement`	MOVE	Required for a form, ignored by headless	`view-bridge.ts`
`language`, `countryCode`, `checkoutSession`	same keys on `transaction()`	MOVE	`countryCode` required; TypeScript also requires `language`, `showStatusScreen`	`transaction-config.ts`
none	`autoContinuePayment`, `cardFormUnfoldedEnable`	new, optional	No action	SDK source
`enableRedesign`, `isDynamicViewEnabled`, `enabledRequiredFields`	not in the public v2 type	REMOVED (type)	Remove for TypeScript	`PaymentOnlyConfigFields`

3.D Required or new behaviour

v1.11	v2	Kind	What to do	Evidence
none	exactly one of `checkoutSession` / `customerSession`	NEW REQUIRED	Both or neither throws	`transaction.utils.ts`
secure field `.render('#sel')`	`.mount('#sel')`	RENAME		core 9.4.1 `SecureFieldV2Instance.mount`
`generateTokenWithInformation` + POST + `continuePayment()`	`tx.start({paymentMethod:{type:'CARD', data:{card:{holderName}}}})`	RENAME	No PCI keys in `data.card` (it throws)	`transaction.utils.ts`
`payment_method.card.detail.{holder_name,number,security_code,expiration_month,expiration_year}`	`paymentMethod.data.card.{holderName,number,securityCode,expirationMonth,expirationYear}`	RENAME	camelCase envelope	docs `headless`
who creates the payment: Seamless = SDK, `startCheckout` + `yunoCreatePayment` = merchant	presence of `createPayment` decides; managed needs session `workflow: "SDK_SEAMLESS"`	NEW REQUIRED	Match each flow to its session workflow	docs `create-payment.mdx`
new payment on the same session after a final result	`The payment on this checkout session already finished...`	BEHAVIOUR	New session and new transaction per retry after a final result	`settled-checkout-session.ts`

3.E CSS, DOM and white label

v1.11	v2	Kind	What to do	Evidence
class prefix `sdk-payments-*`	`sdk-payments-*`	KEEP	Keep selectors; re-check overrides visually (only three classes compared)	the SDK core `STYLE_CLASS_PREFIX`
no `yuno-*` class in 1.11	`yuno-container-spinner-content`, `yuno-container-spinner-ring`, `<style id="yuno-container-spinner-style">`, `data-yuno-placeholder`	KEEP (v2 renders them)	Never report selectors on these. A white-label page on v2 always contains these `yuno` strings	SDK source
`HTMLElement` container without `id`	gets `yuno-view-<random>`	BEHAVIOUR	Give it an `id` on white-label pages	SDK source
`apiUrl`, `assetUrl`	same keys	KEEP	Set them together; proxy `/sdk-static-bundles-ms/*`	`sdk-payments.ts`, white-label docs

3.F `card` option and nested config

v1.11	v2	Kind	What to do	Evidence
`card.cardSaveEnable`	`card.saveCardEnabled`	RENAME + SILENT	Old key hides the save-card checkbox	SDK source
`card.requiredFieldsOrderedEnabled`	none	REMOVED	Delete (unread in both lines)	core `CardStore`
`externalButtons.applePay.topLevelDomain`	not in the public type	REMOVED + SILENT	Ignored: v2 always calls `setApplePayTopLevelDomain({ option: undefined })` and auto-detects the top frame. Delete it	`ApplePayButtonConfig`; SDK source

3.G Behaviour that differs and is easy to miss

v1.11	v2	Kind	What to do	Evidence
`createPayment` first argument is a string	it is an object; the string is `token.token`	BEHAVIOUR	Sending the object as the token fails Create Payment (inferred)	core `types/handlers.ts` `CreatePaymentCallback`
session is the third `createPayment` argument	`token.checkout_session`; the config session goes stale after a retryable decline	BEHAVIOUR	Read the session from the token	SDK source
result callback fires on final results	`onStatus` also fires on non-final retryable results in manual mode	BEHAVIOUR	Do not redirect on every call	SDK source
modal checkout	inline form in the host page	BEHAVIOUR	Size the container	SDK source
mount resolves when shown	`start()` resolving means form mounted, not paid	BEHAVIOUR	Never show success after `await start()`	`transaction.ts`

3.H Features in v1 and absent from v2 (BLOCKED: parity gap)

v1.11	v2	Kind	What to do	Evidence
`unmountSeamlessExternalButtons()`, `unmountSeamlessExternalButton(t)`	none	BLOCKED if the flow needs per-wallet removal	Otherwise delete; wallets stay until the container is removed	docs `seamless` “Removed”
`mountExternalButtons`, `unmountExternalButton`, `unmountAllExternalButtons`	none	BLOCKED	Non-seamless wallet buttons have no v2 form	SDK source
`showLoader()`, `hideLoader()`	none	BLOCKED if the merchant drives the loader by hand	`showLoading(handler)` is the only hook	SDK source
`clickToPay(args)` standalone	none	BLOCKED	In-form Click to Pay via `c2p` config only	SDK source
`renderMode: {type:'modal'\|'element'}`	none; forms render inline at `elementSelector`	SILENT; BLOCKED if a modal is required		SDK source
`card.type: 'step'` (step-by-step form)	none	BLOCKED	Removed; the SDK core `CardDisplayMode` has only `extends`. Verify at runtime what a stray `'step'` renders	core `CardDisplayMode` type
`onlyExpressPaymentMethods`	none	BLOCKED		zero reads on v2
`stickyPayButton`, single or sticky Yuno Pay button	none	BLOCKED		removed from v2
`__internal`	none	BLOCKED		SDK source
`onChange` on the card enrollment form, `submit()` for enrollment	never reports; throws	BLOCKED		SDK source
redirect-return handling, `PaymentStatus` registry	none (`sdk.handleRedirect` was removed before release)	BLOCKED	Verify at runtime which v1 call the merchant relies on	SDK source

Checks

Report each as PASS / FAIL / N/A with file:line, and quote the line. Each title ends with the research check id and a severity: B blocking (no payment or no result), H high (feature silently lost or wrong outcome), M medium (degraded UX), L low (hygiene), P parity gap (report as blocked, never as a change to make).

1. Global and ready event (M1, B)

Look: window.Yuno, Yuno.initialize, yuno-sdk-ready. Still v1: any hit. Change: window.SdkPayments, sdk-payments-ready, check the global before listening. Symptom: Yuno is not defined, init never runs.

2. Script URL and loader (M2, B)

Look: script tags, loadScript, sdk-static-bundles-ms. Still v1: /v1.11/, loadScript() without baseUrl, sri: true; also wrong: /v2/, /v2.2/. Change: full v2.x.y URL; EU pages check the EU host has the version. A v2.0.0 pin that matches the public docs sample is valid, not a finding. Symptom: sdk.transaction is not a function, or 404.

3. v1 entry points (M3, B)

Look: the second grep. Still v1: any call. Change: per Mapping; REMOVED rows say “no replacement”. Symptom: yuno.startCheckout is not a function.

4. Mode and session workflow (M4, B)

Look: v1 mode (Seamless = managed; startCheckout with yunoCreatePayment = manual) and the backend POST /v1/checkout/sessions body. Change: managed has no createPayment and uses workflow: "SDK_SEAMLESS"; manual has createPayment and the default workflow. Symptom: onStatus INTERNAL_ERROR.

5. `createPayment` signature (M5, B)

Look: (yuno)?[cC]reatePayment, continuePayment. Still v1: two or three parameters, the first used as a string, the config session used, continuePayment(), notifyError(). Change: one token; send token.token and token.checkout_session; return a Promise that settles on every path; reject on failure. Rename yunoCreatePayment: the 2.2.0 code keeps an alias, but mode selection reads only createPayment (verify at runtime). Symptom: Create Payment 4xx, stale-session payment, form stuck.

6. Result callbacks and statuses (M6, B)

Look: yunoPaymentResult, paymentResult, yunoError, enrollmentStatus, the v1 status strings. Change: one onStatus(result) on backend statuses plus INTERNAL_ERROR and USER_CANCEL; SDK error codes (FORM_INVALID, MERCHANT_CREATE_PAYMENT_FAILED, ELEMENT_NOT_FOUND) are in message.code and substatus is null, so never branch on substatus for them; FORM_INVALID and retryable declines are not final. Symptom: no result handled, console warns ...created without an onStatus function....

7. Rendering model (M7, H)

Look: renderMode, viewContainer, overlay CSS. Change: a sized container and elementSelector on transaction(). Symptom: form inline instead of modal; Wrong element selector. Blocked if the merchant requires a modal.

8. Status screen option (M8, H)

Look: showPaymentStatus. Change: showStatusScreen. Symptom: the SDK result screen shows anyway and onStatus waits for the shopper to dismiss it. The public v2.1.0 changelog still says showPaymentStatus (doc drift).

9. Loading (M9, M)

Look: onLoading, showLoading, showLoader, hideLoader. Change: showLoading: (isLoading) => void, drop type; a boolean must go. Symptom: a kept onLoading still runs, so nothing breaks until both are set; showLoading: true throws a minified TypeError; showLoading: false silently shows the SDK loader. Blocked where the loader is driven by hand with showLoader/hideLoader.

10. List selection and Pay (M10, B)

Look: paymentMethodSelected, startPayment, mountCheckout. Change: getPaymentMethodsViews, store onPaymentSelected, Pay calls start({paymentMethod: selected}), ignore selectionSource: 'auto'. Symptom: the list shows and nothing pays.

11. External buttons (M11, H)

Look: mount(Seamless)?ExternalButtons, unmount*ExternalButton*. Change: one view mount per wallet, awaited or caught. Symptom: wallet missing, unhandled rejection. The non-seamless family is blocked.

12. `card` keys (M12, H)

Look: cardSaveEnable, requiredFieldsOrderedEnabled, type: 'step'. Change: saveCardEnabled; drop the other. Symptom: save-card checkbox silently gone. 'step' is blocked.

13. Removed options (M13, H)

Look: onlyExpressPaymentMethods, stickyPayButton, __internal, renderMode. Change: report each; decide with the merchant. Symptom: behaviour silently missing. onLoading is not in this list: it is still called (M9). The parity-gap items are blocked.

14. Secure Fields (M14, B)

Look: secureFields(, .render(, generateToken*, enableV2, enableMultiplesCard. Change: tx.secureFields(), .mount, pay with start and only non-PCI keys in data.card (holderName, type, installment, customer, vaultOnSuccess); gate Pay on !error && isDirty. Symptom: render is not a function, PCI-keys error.

15. Headless (M15, B)

Look: apiClientPayment, generateToken, getThreeDSecureChallenge, payment_method.card.detail, holder_name. Change: camelCase data.card plus createPayment; delete 3DS code; one headless start() per transaction. Symptom: tokenization error, empty fields.

16. Enrollment (M16, B)

Look: mountEnrollmentLite, apiClientEnroll, continueEnrollment, vaultedToken in callbacks. Change: transaction({customerSession}).start(...); success is ENROLLED (UI) or CREATED (headless); vaulted token from the backend. Symptom: undefined token stored.

17. Fraud and status screen (M17, H)

Look: executeFraudCheck, mountFraud, mountStatusPayment. Change: executeFraudCheck becomes sdk.antifraud, checked on status === 'success'; mountFraud is a card payment UI, so it becomes a normal transaction({...}) plus start({paymentMethod:{type:'CARD'}}) with its yunoCreatePayment moved to createPayment(token), per the public fraud migration page; transactionStatus with elementSelector. Symptom: undefined fingerprints sent; not a function; a deleted mountFraud removes a payment flow.

18. Utility calls (M18, H)

Look: isPaymentMethodAvailable, updateCheckoutSession, refreshPromotionQuote, unmountSdk on the instance. Change: move them to the transaction; keep clearApiCache, setCanaryMode. Symptom: ... is not a function.

19. `initialize` lifecycle (M19, H)

Look: where and how often initialize runs (render bodies, effects, per checkout, changing applicationSession). Change: one instance per page with stable args, one transaction per checkout. Symptom: This SdkPayments instance is no longer active: a later initialize() replaced it... and the form vanishes. Two calls on a superseded instance do not throw: antifraud() resolves {status:'error'} and isPaymentMethodAvailable() resolves false.

20. Unmount (M20, M)

Look: unmountSdk(, effect cleanups. Change: await tx.unmount(); treat the USER_CANCEL it delivers as teardown, not abandonment. Symptom: error screen on navigation. React StrictMode remounts are untested in v2: verify at runtime.

21. Retry (M21, H)

Look: isRetrying, newCheckoutSession, custom retry code. Change: manual mode keeps the form after a retryable decline (session in token.checkout_session); after a final result, new session and new transaction. Symptom: retry broken; The payment on this checkout session already finished....

22. CSS, DOM, white label (M22, M)

Look: CSS and JS selectors on SDK class names and attributes. Still v1: a selector on a v1.11 name that v2 does not render. Exempt: yuno-container-spinner-content, yuno-container-spinner-ring and data-yuno-placeholder, which v2 renders. Change: keep sdk-payments-; re-check each override visually (only three classes were compared); give an HTMLElement container an id, or v2 adds yuno-view-<random>. A white-label page on v2 always contains the spinner yuno names; report that as a note, not a failure. Symptom: lost styling.

23. TypeScript types (M23, L)

Look: @yuno-payments/sdk-web-types, YunoSDK types. Change: a local v2 declaration written from the public v2 migration pages. Symptom: compile errors or silent any.

24. Parity-gap review (M24, P)

Look: every BLOCKED row. Report the flow as “blocked: parity gap, do not migrate this flow yet” and keep it on v1.11. Ask your Yuno contact for the current parity-gap list and cross-check it.

25. Rollout and rollback (M25, M)

Look: a flag or per-environment switch for the script URL. Change: keep the v1.11 path, roll v2 by flag, test on sandbox first. Symptom: no way back.

Report format

PART 1  Migration list (B first, then H, M, L)
B  M5   src/checkout/pay.ts:41    yunoCreatePayment(ott, info, cs) -> createPayment(token), send token.token
B  M6   src/checkout/pay.ts:58    yunoPaymentResult -> onStatus; 'FAIL' -> DECLINED/REJECTED/INTERNAL_ERROR
H  M12  src/checkout/config.ts:9  card.cardSaveEnable -> card.saveCardEnabled
KEEP    src/index.html:12         window.SdkPayments / sdk-payments-ready already v2-compatible

PART 2  Parity gaps (flows that cannot migrate yet)
P  M11  src/wallets.ts:20  mountExternalButtons (non-seamless wallets): blocked: parity gap, do not migrate this flow yet
P  M13  src/cart.ts:77     stickyPayButton: blocked: parity gap, do not migrate this flow yet

One line per finding: severity, check, file:line, the one-line change. End with the v1 and v2 script versions found and whether the repo is v1-only or mixed.

Diagnostics to capture

The script URL actually loaded (Network tab) and the value of typeof sdk.transaction (function on v2 only).
The checkout session id, its workflow, and the UTC time of the attempt.
Every onStatus payload received (status, substatus, message.code, message.reason).
Console lines starting with SdkPayments, and any thrown message from transaction(), start() or mount().
The createPayment request your backend sent (token field and session, personal data removed).

Verify at runtime

These could not be confirmed by reading code; test them before relying on them: what a lone yunoCreatePayment (v1 signature) does once merged into createPayment; what card.type: 'step' renders; transaction.unmount() under a React StrictMode remount; the full CSS class list; EU availability of v2.2.0. Part of this was read from unreleased v2 code, so some behaviour may not be in the 2.2.0 bundle yet. Sources: the Web SDK 1.11.47 and 2.2.0 source code, the v2 API report, the npm loader @yuno-payments/sdk-web, @yuno-payments/sdk-web-types and the public Yuno docs (the “SDK” tab, its migration guides and changelog, and the white-label page); CDN probes. Research date 2026-10-29.

​What v2 keeps (do not report these as blocking)

​How to use

​Mapping

​3.A Bootstrap and globals

​3.B Entry points and flow modes

​3.C Option and callback names

​3.D Required or new behaviour

​3.E CSS, DOM and white label

​3.F card option and nested config

​3.G Behaviour that differs and is easy to miss

​3.H Features in v1 and absent from v2 (BLOCKED: parity gap)

​Checks

​1. Global and ready event (M1, B)

​2. Script URL and loader (M2, B)

​3. v1 entry points (M3, B)

​4. Mode and session workflow (M4, B)

​5. createPayment signature (M5, B)

​6. Result callbacks and statuses (M6, B)

​7. Rendering model (M7, H)

​8. Status screen option (M8, H)

​9. Loading (M9, M)

​10. List selection and Pay (M10, B)

​11. External buttons (M11, H)

​12. card keys (M12, H)

​13. Removed options (M13, H)

​14. Secure Fields (M14, B)

​15. Headless (M15, B)

​16. Enrollment (M16, B)

​17. Fraud and status screen (M17, H)

​18. Utility calls (M18, H)

​19. initialize lifecycle (M19, H)

​20. Unmount (M20, M)

​21. Retry (M21, H)

​22. CSS, DOM, white label (M22, M)

​23. TypeScript types (M23, L)

​24. Parity-gap review (M24, P)

​25. Rollout and rollback (M25, M)

​Report format

​Diagnostics to capture

​Verify at runtime