Invalid API Key provided

[axiftaj]

Describe the bug
I am trying to collect credit card information from user using stripe package flutter_stripe: ^11.5.0 when I try to store credit card on stripe server it send below exception, my publish key is 100% correct.

StripeException(error: LocalizedErrorMessage(code: FailureCode.Failed, localizedMessage: There was an unexpected error -- try again in a few seconds, message: Invalid API Key provided: pk_test_***********************************************************************************************fyDZ, stripeErrorCode: , declineCode: null, type: invalid_request_error))

To Reproduce
Steps to reproduce the behavior:

1. Add the stripe package and mention your key in main function as showing below

void main() async {

  WidgetsFlutterBinding.ensureInitialized();
  Stripe.publishableKey = 'pk_test_your_key' ;
  await Stripe.instance.applySettings();
  runApp(const MyApp());
}

2. here is my code to help in details

  const AddCardScreen({super.key});

  @override
  State<AddCardScreen> createState() => _AddCardScreenState();
}

class _AddCardScreenState extends State<AddCardScreen> {
  CardFieldInputDetails? _cardFieldInputDetails;
  bool _loading = false;

  void _createPaymentMethod() async {
    if (_cardFieldInputDetails == null || !_cardFieldInputDetails!.complete) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text("Please enter complete card details")),
      );
      return;
    }

    setState(() => _loading = true);

    try {
      final paymentMethod = await Stripe.instance.createPaymentMethod(
        params: PaymentMethodParams.card(
          paymentMethodData: PaymentMethodData(billingDetails: BillingDetails(
            name: 'Asif Taj',
            email: 'asif@example.com',
          )),
        ),
      );

      setState(() => _loading = false);

      showDialog(
        context: context,
        builder: (_) => AlertDialog(
          title: const Text("Payment Method Created"),
          content: Text("ID: ${paymentMethod.id}"),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: const Text("OK"),
            )
          ],
        ),
      );

      // Optional: send to your backend for saving
      // await sendPaymentMethodToServer(paymentMethod.id);

    } catch (e) {
      print(e);
      setState(() => _loading = false);
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text("Error: $e")),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Stripe Save Card')),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            const Text("Enter your card details:"),
            const SizedBox(height: 16),
            CardField(
              onCardChanged: (card) {
                setState(() => _cardFieldInputDetails = card);
              },
              decoration: const InputDecoration(border: OutlineInputBorder()),
            ),
            const SizedBox(height: 24),
            ElevatedButton(
              onPressed: _loading ? null : _createPaymentMethod,
              child: _loading
                  ? const CircularProgressIndicator()
                  : const Text("Save Card"),
            ),
          ],
        ),
      ),
    );
  }
}```


4. Observe a failure with exception (including the part of the stack trace, belonging to this package): 

`StripeException(error: LocalizedErrorMessage(code: FailureCode.Failed, localizedMessage: There was an unexpected error -- try again in a few seconds, message: Invalid API Key provided: pk_test_***********************************************************************************************fyDZ, stripeErrorCode: , declineCode: null, type: invalid_request_error))`


**Expected behavior**
Expected behavior, it should have been returning me **paymentMethod.id** 

**Smartphone / tablet**
 -  Heppening on all phone

[Labeebkhan]

Hi @axiftaj ,

Gonna Let You Know that I am Using LLM to Answer Your Query

After reviewing the reported issue:
StripeException(error: ... Invalid API Key provided: pk_test_************************)

It’s clear that the root cause of the problem is due to an invalid or improperly configured `publishableKey being set in the app. Let me walk through the problem and solution step by step.

Root Cause

The error message:
Invalid API Key provided: pk_test_***************

occurs when the publishableKey provided to Stripe.publishableKey is:

• Incorrect (copied partially or with formatting issues)
• Expired, revoked, or deleted from the Stripe dashboard
• Restricted (e.g., key has limited scopes or IP restrictions)
• Used in the wrong environment (test key used in live mode, or vice versa)

Even if the key appears correct, this error means Stripe could not authenticate it during your call to Stripe.instance.createPaymentMethod(...).

---

Solution Steps

1. Use Correct and Complete pk_test_... Key

Please follow these steps:

• Go to [Stripe Dashboard → Developers → API Keys](https://dashboard.stripe.com/test/apikeys)
• Copy the full Publishable key (starts with pk_test_)
• Paste it directly in your main.dart like so:

void main() async { WidgetsFlutterBinding.ensureInitialized(); Stripe.publishableKey = 'pk_test_51YourRealKeyCopiedFromDashboard'; await Stripe.instance.applySettings(); runApp(const MyApp()); }

Avoid copy-pasting from emails, chats, or documents that may truncate the key or mask it with asterisks.

2. Ensure You Are in Test Mode

If using a pk_test_... key, ensure you are using Stripe’s test environment and test card numbers, for example:

Card Number: 4242 4242 4242 4242 Expiry: 12/34 CVC: 123 ZIP: 12345

3. No Backend Needed for Basic PaymentMethod Creation

If your only goal is to create a PaymentMethod (not save the card), then your existing frontend logic is mostly correct — provided the key is valid.

However, if you want to save cards for future payments, Stripe requires a SetupIntent, which must be created from a backend server (Node.js, Firebase, Python, etc.).

Frontend-only saving of cards is not supported.

🛠️ Example Working Integration (Frontend Only - Test Mode)

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  Stripe.publishableKey = 'pk_test_51YourRealKey';
  await Stripe.instance.applySettings();
  runApp(const MyApp());
}

With the following test card:

Card: 4242 4242 4242 4242  
Exp: 12/34  
CVC: 123

This will allow successful creation of a PaymentMethod.

Summary

To resolve the issue:

• Use the correct, full pk_test_... publishable key
• Confirm that the key is not expired or deleted
• Use test cards in the test environment
• Use backend for SetupIntent if saving cards for reuse

Issue Status: Resolved (Pending Key Correction)

Please replace the publishable key with the valid one from your dashboard and re-test. If you’re still facing issues, feel free to share the masked version of your key (pk_test_51XXXX...) and I’d be happy to double-check the setup.

Thanks!
Labeeb Khan
Flutter Developer & Stripe Integration Specialist