adWMG Checker: ads.txt/sellers.json

Lines Checker is an essential, zero-dependency Chrome Extension built specifically for AdOps engineers, publishers, and QA teams. It streamlines the validation of ads.txt and app-ads.txt inventories by cross-referencing seller IDs against a configurable sellers.json registry directly in your browser.

Instead of manually parsing complex text files or running external scripts, this extension surfaces syntax errors, configuration mismatches, and supply path optimization (SPO) insights in real-time.

Key Features:
• Comprehensive Validation: Instantly check ads.txt and app-ads.txt files for the active tab.
• sellers.json Cross-Referencing: Automatically verify seller IDs against a customizable sellers.json endpoint to ensure registry alignment and highlight missing entries.
• Advanced Error Detection: Identify critical syntax errors and commented-out data lines that generic crawlers often miss.
• Soft-404 Protection: Smart detection algorithms catch false-positive text files returned as HTML.
• Consistency Checks: Validates OWNERDOMAIN and MANAGERDOMAIN against the active tab's domain.
• In-Depth Analyzer Workspace: Get instant access to line statistics, duplicate detection, and DIRECT vs. RESELLER ratios to understand your SPO metrics.
• Smart Filtering: In-popup controls allow you to filter and display specific brand-matching lines or the complete dataset.
• On-Page Overlay: Injects a lightweight overlay for direct ads.txt and app-ads.txt page inspection, immediately surfacing contact and domain fields.
• Freshness Indicators: Extracts HTTP metadata (Last-Modified) so you always know when the file was last updated by the operator.
• Dynamic Badge Updates: Real-time extension badge counters show per-tab line match counts at a glance.

Built for Performance and Privacy:
This tool is built on Manifest V3 and requires zero external UI frameworks or runtime dependencies. It executes locally in your isolated browser context, utilizing a retry-aware fetch pipeline to handle unstable endpoints gracefully. All custom configurations, including your preferred sellers.json URL, are stored locally on your device.
Simplify your AdOps troubleshooting, reduce manual checks, and ensure your programmatic inventory is configured perfectly with this powerful validator.