Errors

onError fires when a run never reaches a settled outcome at all. This is distinct from onClose, which means the person dismissed a run that did open. Every message today is a plain string. There is no error code to branch on.

VerifyYou.vycheck(
    context = this,
    session = sessionId,
    onComplete = { result -> /* ... */ },
    onError = { message ->
        // An empty session, a run already in progress, or the hosted
        // page failed to load or start. Mint a fresh session and let them retry.
        Log.e("MyApp", "verifyyou: $message")
    },
)

VerifyYou.vycheck(
    from: self,
    session: sessionId,
    onComplete: { result in /* ... */ },
    onError: { message in
        // An empty session, a run already in progress, or the hosted
        // page failed to load or start. Mint a fresh session and let them retry.
        print("verifyyou:", message)
    }
)

try {
  const { token } = await vycheck({ session: sessionId });
  if (!token) {
    // They closed it without finishing. Not an error. Let them retry.
  }
} catch (err) {
  // An empty session, a run already in progress, or the hosted page
  // failed to load or start. Mint a fresh session and let them retry.
  const message = err instanceof Error ? err.message : String(err);
  console.error("verifyyou:", message);
}

When it fires

Cause	Message names
`session` is empty or blank	that it must not be empty
A run is already presenting	that a verification is already in progress
`appBase` produced an unbuildable URL	that the hosted URL failed to build
The hosted page failed to load, answered with an HTTP error, or its WebView crashed	that the page failed to load, returned an error, or crashed
The hosted flow did not load within 20 seconds of the `vycheck()` call	`the verification page did not start`
The device’s WebView is too old (Android only)	`this device's WebView is too old to run verification`
The verification screen did not open. On Android, the system refused to start it. On iOS, the screen you passed as `from` is not on screen, or is being dismissed.	`could not open the verification screen`

The Android only row also reaches a React Native app running on Android. An empty session reports an error. A bad, expired or already used session does not. The web SDK makes no network call when it opens a session by id, so nothing rejects at call time. The problem shows up on the hosted page itself, inside the screen. The person can close that screen, which calls onClose. The flow itself runs on the browser SDK inside the native screen, so anything the browser SDK rejects with reaches onError with the same message.

Dismissal is not an error

Closing the screen without finishing calls onClose, or on React Native resolves the promise with { token: null, verified: false, vyc: null }. Look for a missing token instead. Do not treat this as a rejection.

React Native: onError and the promise both fire

A native error calls onError and rejects the returned promise with a real Error, so err.message reads the same string onError receives. Use whichever fits your code: the callback for a component that never awaits the handle, catch for one that does.

Integrating

Server API

Browser SDK

Mobile SDKs

Reference

When it fires

Dismissal is not an error

React Native: onError and the promise both fire

​When it fires

​Dismissal is not an error

​React Native: onError and the promise both fire

When it fires

Dismissal is not an error

React Native: onError and the promise both fire