Universal Coupon Code Auto-Tester

WHAT IT DOES

This script automatically tests coupon codes on any e-commerce checkout page, saving you the hassle of manually typing and applying each code. You enter a list of coupon codes (separated by semicolons or new lines) in the settings panel, and the script sequentially enters each code into the coupon input field, clicks the "Apply" button, and checks whether a discount was applied. Results show which codes worked, which failed, and the discount amount if detected. A "Quick test" button lets you test a single code instantly. A history section tracks all successfully tested coupon codes for future reference. The script works on any site with a coupon input field.

WHERE IT RUNS

The script runs on all websites (*://*/*), making it truly universal. It works on checkout and cart pages from Amazon, Walmart, Target, Best Buy, eBay, and any other e-commerce site. It supports both desktop and mobile views.

HOW TO USE

After installation, the settings panel appears on the left side of the screen with the gear emoji (⚙️). Open the panel to configure the script:

- The "Enable auto-tester" toggle enables or disables the script.

- Enter your coupon codes in the "Coupon codes" text area, separated by semicolon (;) or new line.

- Click "Test All Coupons" to start testing all codes automatically.

- For a single code, enter it in the "Quick Test" input and click "Quick Test."

- The "Results" section shows which codes worked and which failed.

- The "History" section shows previously successful codes.

The script runs automatically on the current page—just go to any checkout page and start testing.

TECHNICAL SECTION — REAL MECHANISM

The script detects the coupon code input field using a comprehensive set of selectors including input[name="coupon_code"], input[name="discount_code"], input[name="promo_code"], input[placeholder*="coupon"], input[aria-label*="coupon"], and many others. It detects the "Apply" button using selectors like button[type="submit"], button[value="Apply"], .apply-button, and by finding buttons near the coupon input. For each coupon code, the script sets the input value and dispatches "input," "change," "keydown," and "keyup" events to trigger React/Vue event listeners. It then clicks the apply button and waits 3 seconds for the page to update. To determine success, the script compares the total price before and after applying the code, checks for success messages like "applied" or "discount," and looks for error messages like "invalid" or "expired." The results are displayed in the panel with green checkmarks for successful codes and red crosses for failures. The test runs sequentially with a 1.5-second delay between codes to avoid rate limiting.

THE PANEL

The settings panel is built with BotGentz's BGPanel component. It is draggable via its header, allowing you to reposition it anywhere on the screen. The panel snaps to the left edge by default but can be moved freely. Click the gear emoji to collapse the panel into a small bubble, and click the bubble to expand it again. The panel remembers its position per page session. Press the Escape key to quickly close or minimize the panel. The panel includes a status flash bar that provides visual feedback when settings are changed or actions are performed. All settings and history save automatically via GM_setValue.

PLEASE NOTE

This script requires the free BotGentz browser extension to run. It does not function as a standalone Chrome extension and does not use chrome.* APIs. Some e-commerce sites may have anti-bot measures or CAPTCHAs that prevent automated coupon testing. The script works on most sites but may not work on sites with non-standard coupon input behavior. The "Test All Coupons" function sequentially tests codes and may take time for large lists. The script stores coupon history locally—this data is not synced across devices. The script never reads or writes password fields, hidden inputs, or file inputs. All DOM operations use safe methods (style properties, textContent, appendChild) and never use innerHTML.