> ## Documentation Index
> Fetch the complete documentation index at: https://ext.eplus.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Payment Sandbox Helper

> Generate and fill PayPal Sandbox and Stripe test card data from a browser sidebar

<Info>
  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.
</Info>

**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.

<CardGroup cols={2}>
  <Card title="PayPal Sandbox testing" icon="paypal" href="/payment-sandbox-helper/usage">
    Generate Luhn-valid Visa, Mastercard, American Express, Diners Club, Maestro, CUP, and JCB test data, or select PayPal-specific failure triggers.
  </Card>

  <Card title="Stripe test scenarios" icon="stripe">
    Browse predefined Stripe cards grouped by successful payment, decline, and 3D Secure scenarios.
  </Card>

  <Card title="Automatic form filling" icon="wand-magic-sparkles">
    Fill card number, expiry, CVV, cardholder name, and country into supported payment forms.
  </Card>

  <Card title="Developer-friendly sidebar" icon="sidebar">
    Keep test data visible while working in Chrome or Firefox without repeatedly switching tabs.
  </Card>
</CardGroup>

## 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`.

<Warning>
  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.
</Warning>

## 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.

## Get started

<CardGroup cols={3}>
  <Card title="Install" icon="download" href="/payment-sandbox-helper/installation">
    Build the Chrome or Firefox package and load it in the browser.
  </Card>

  <Card title="Use the helper" icon="play" href="/payment-sandbox-helper/usage">
    Open the sidebar, choose a provider, and fill a sandbox checkout form.
  </Card>

  <Card title="View source" icon="github" href="https://github.com/ePlus-DEV/payment-sandbox-helper">
    Review the source code, releases, and project issues.
  </Card>
</CardGroup>


## Related topics

- [FAQ](/payment-sandbox-helper/faq.md)
- [Installation](/payment-sandbox-helper/installation.md)
- [ePlus.DEV Browser Extensions](/index.md)
- [Usage](/payment-sandbox-helper/usage.md)
- [Features](/payment-sandbox-helper/features.md)