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Payment Sandbox Helper is intended only for development and sandbox environments. Generated card numbers are test data and must not be used for real payments or production checkout attempts.
Payment Sandbox Helper is an open-source browser extension for developers testing card-payment flows. It provides PayPal Sandbox cards, PayPal error triggers, Stripe test cards, automatic form filling, and input-level context-menu actions from a persistent browser sidebar.

PayPal Sandbox testing

Generate Luhn-valid Visa, Mastercard, American Express, Diners Club, Maestro, CUP, and JCB test data, or select PayPal-specific failure triggers.

Stripe test scenarios

Browse predefined Stripe cards grouped by successful payment, decline, and 3D Secure scenarios.

Automatic form filling

Fill card number, expiry, CVV, cardholder name, and country into supported payment forms.

Developer-friendly sidebar

Keep test data visible while working in Chrome or Firefox without repeatedly switching tabs.

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Supported environments

The content script currently runs on:
  • PayPal and PayPal Sandbox pages.
  • Stripe pages.
  • localhost and 127.0.0.1 development sites.
  • Google App Engine applications under *.appspot.com.
A Luhn-valid number is not automatically accepted by every sandbox. Use cards and error triggers that match the payment provider and scenario being tested. Secure cross-origin iframes may also require manual copy and paste.

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Main capabilities

  • Generate randomized PayPal-style test cards with valid checksums.
  • Trigger common PayPal decline and validation responses.
  • Select Stripe success, decline, and 3DS cards.
  • Fill an entire detected card form from the sidebar.
  • Fill the currently focused field through the browser context menu.
  • Configure the default country, cardholder name, card appearance, and interface language.
  • Store preferences locally through the browser extension storage API.

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Get started

Install

Build the Chrome or Firefox package and load it in the browser.

Use the helper

Open the sidebar, choose a provider, and fill a sandbox checkout form.

View source

Review the source code, releases, and project issues.

Related topics

FAQInstallationePlus.DEV Browser ExtensionsUsageFeatures