🛡️ Ads.txt / App-ads.txt & Sellers.json Validator (Chrome Extension)

A comprehensive AdOps utility tool built for Chrome (Manifest V3). It automates the validation of ads.txt and app-ads.txt files, cross-references inventory against a sellers.json registry, and highlights syntax errors or configuration mismatches in real-time.

Key Features

1. Advanced Parsing & Validation

• Smart Brand Parsing: Intelligently extracts the core brand name from complex sellers.json URLs (e.g., handles api.applovin.com or cdn.pubmatic.com correctly by ignoring subdomains).
• Soft 404 Detection: Automatically detects when a server returns an HTML error page masquerading as a text file (prevents false positives).
• Syntax Highlighting: Flags critical errors, such as commented-out lines or invalid characters that would cause crawlers to ignore the record.
• Owner Domain Validation: Validates the OWNERDOMAIN field against the actual site URL (Returns: MATCH, MISMATCH, or NOT FOUND).

2. Sellers.json Cross-Reference

• Inventory Matching: Automatically fetches sellers.json (defaults to adwmg.com, configurable) with local caching (1-hour TTL) to optimize performance.
• Discrepancy Detection: Highlights ads.txt entries where the Seller ID is missing from the associated sellers.json file.
• Real-time Filtering: Filters lines to show only those related to the configured SSP/Brand.

3. UI & UX

• Live Line Counters: Tabs now display the exact count of valid lines for ads.txt and app-ads.txt.
• Smart Status Badges: Visual indicators for every line:
  • (X) Critical Syntax Error.
  • (!) ID Mismatch (Warning).
• Last Modified Date: Displays when the file was last updated on the server.
• Configurable Settings: Users can set a custom sellers.json URL via the settings panel.

Technical Stack

• JavaScript (ES6+): Pure Vanilla JS, modular architecture with shared utilities.
• Chrome APIs:
  • chrome.scripting: For injecting analysis scripts into the active tab.
  • chrome.storage.local: For caching the sellers.json file.
  • chrome.action: For updating the dynamic badge counter.
• CSS3: Custom responsive layout with Flexbox and dark/light mode compatibility elements.

Installation (Developer Mode)

1. Clone or download this repository.
2. Open Chrome and navigate to chrome://extensions.
3. Enable Developer mode (toggle in the top right corner).
4. Click Load unpacked.
5. Select the folder containing manifest.json.

Usage

1. Navigate to any website (e.g., nytimes.com).
2. The extension icon will update with a number indicating valid lines found for the configured SSP.
3. Click the icon to open the popup:
   • Tab 1 (sellers.json): Shows matched records from the SSP's registry.
   • Tab 2 (ads.txt): Shows the site's ads.txt content with syntax highlighting.
   • Tab 3 (app-ads.txt): Same analysis for mobile app inventory.
4. Settings: Click the ⠸ icon to change the target sellers.json URL or force refresh the cache.

Validation Logic Details

The extension performs the following checks on every line:

// Simplified Logic Flow based on popup.js
lines.forEach(line => {
    // 1. Filter by Brand (e.g., "adwmg")
    if (line.toLowerCase().includes(brandName)) {
        
        // 2. Critical Syntax Check
        // Detects valid data that is accidentally commented out (e.g., "# adwmg.com, 12345...")
        if (startsWithSpecialChar(line) && line.includes(",")) {
            markAsCriticalError("Error: Data line is commented out!");
        }

        // 3. Sellers.json Cross-Reference
        const sellerId = extractSellerId(line); // Extracts the 2nd field
        if (sellerId && !isIdInSellersJson(sellerId)) {
            // Checks if this specific ID exists in the fetched sellers.json cache
            markAsWarning("Warning: ID not found in sellers.json");
        }
    }
});
}```

## Project Structure

├── manifest.json      # Extension configuration (Manifest V3)
├── background.js      # Service Worker: Handles fetching, caching (sellers.json), and badge updates
├── overlay.js         # Content Script: Injects the "Domains Found" overlay directly onto .txt pages
├── popup.html         # Main Extension UI: Tabs layout and container
├── popup.css          # Styling: Dark/Light theming, badges, and scrollbars
├── popup.js           # Core Logic: Parses text files, runs validation, and renders results
└── utils.js           # Shared Utilities: URL cleaning and Brand Name extraction logic