Flutter SDK for embedded wallet

Embedded Wallets (Web3Auth)
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Thanks — this is an error report (session recovery) so I looked through the Embedded Wallets / web3auth_flutter docs for likely causes.

Short summary of likely causes and quick checklist to try now

  • Missing hand-off of the deep-link payload to the Flutter/Web3Auth SDK after the browser redirect. The SDK needs the returned URL (the #b64Params payload) to complete session reconstruction.
  • initialize() being called before the redirect is processed (order/timing).
  • onNewIntent not actually setting the Activity intent for Flutter (so Dart never sees the deep link).
  • Fragment/params being lost (some Android browsers/flows can strip # fragments) or not logged/forwarded.
  • Secure storage / key store issues (rare) or a clientId / Sapphire network / connection mismatch that would prevent reconstructing the same key.

Checklist (do these in order)

  1. Verify your Android MainActivity.onNewIntent:

    • Call super.onNewIntent(intent) and setIntent(intent). Example minimal pattern:
      onNewIntent(Intent intent) {
      super.onNewIntent(intent);
      setIntent(intent);
      // log intent.getDataString() to confirm full w3a://…#b64Params=…
      }
    • Log intent.getDataString() and intent.getData() to confirm the fragment (b64Params) is present.

  2. Forward the URL to Web3Auth in Flutter immediately after the redirect:

    • If you use the SDK helper, call the redirect handler (eg. Web3AuthFlutter.notifyOnRedirect(uriString) or the SDK’s documented callback handler) so the SDK can finish session recovery.
    • Make sure this hand-off happens before you call any session-dependent methods (getPrivKey / initialize dependent on recovered session).

  3. Handle both warm and cold starts:

    • For cold start (app killed → opened by deep link) ensure you read the initial intent / initialUri on startup (getInitialUri or equivalent) and call the SDK redirect handler.
    • For warm start use onNewIntent + setIntent as above.

  4. Confirm intent contains the fragment (b64Params). If it’s missing, try a browser that preserves fragments or change the redirect sending approach (or confirm the OAuth flow isn’t stripping it).

  5. Sanity checks:

    • Clear app data and retry (rule out stale/corrupt secure storage).
    • Verify Client ID, Sapphire network (devnet vs mainnet), and connection config match the session you started — mismatches make reconstruction fail.
    • Check web3auth_flutter 6.3.0 release notes / GitHub issues for session recovery bugs.

If this doesn’t fix it, please share (paste):

  • MainActivity.onNewIntent implementation (Java/Kotlin)
  • Dart code where you call Web3AuthFlutter.initialize() and any redirect-handling call (notifyOnRedirect or similar)
  • The logs you see right after redirect (intent log and the initialize() PlatformException stack if available)

I searched the Embedded Wallets / web3auth_flutter docs for redirect & session-handling guidance while preparing this; if you want, paste the two code snippets above and I’ll review them quickly.

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