Catalog third-party scripts and estimate their performance impact. Categorize by type (analytics, ads, social) and suggest loading strategies.
A landing page can look lean and still load a dozen third-party scripts. This tool takes the page's HTML, or just its script tags, and turns it into a catalog: every third-party script listed, sorted into a category (analytics, ads, social, tag manager, essential), with a relative impact estimate and a suggested loading strategy for each. The estimate is derived from what your paste shows - script count, synchronous versus async or defer loading - not from network measurements. The usual surprise: a page with one tag-manager snippet can really be running a dozen scripts, none visible until the manager loads.
A concrete input and expected output from the current implementation.
Input
<script src="https://www.google-analytics.com/analytics.js"></script> <script src="https://www.googletagmanager.com/gtm.js"></script> <script async src="https://securepubads.g.doubleclick.net/tag/js/gpt.js"></script> <script async defer src="https://platform.twitter.com/widgets.js"></script>
Expected output
Domain Category Loading Impact Suggestion google-analytics.com Analytics synchronous high load async, or lazy after first paint googletagmanager.com Tag manager synchronous high audit what it injects; keep only needed containers securepubads.g.doubleclick.net Ads async medium keep async; it blocks nothing but still uses bandwidth platform.twitter.com Social async + defer low fine as is; or gate on user interaction
The loading-mode column comes straight from the tags: the first two are plain synchronous tags, which block rendering until they download and run, so they score high, while the ad script is async and the social widget is deferred, so they rank lower. Categories follow the vendor domain.
You paste HTML; the tool extracts every script tag and keeps those whose src points outside the page's own origin. It matches each host against known vendor domains and assigns a category - analytics, ads, social, tag manager, essential, or unknown - and records how the tag loads: plain synchronous, async, or defer. The result is a table of every script with its domain, category, and loading mode.
Each script gets an ordinal impact score - high, medium, or low - from heuristics: a synchronous script blocks parsing until it downloads and runs, so it scores higher than an async one. The tool then suggests a loading strategy per category: defer analytics, load social widgets on interaction, keep tag managers and essential scripts, and audit what a tag manager injects.
Probably, but verify with a real measurement. The score ranks scripts by how they load; it cannot see what they do after loading, and some high-ranked scripts are essential - payments, authentication, the ad code that funds the page. Remove or defer only what the business can live without, then compare timings before and after.
No. The tool works on what you paste - it does not crawl or fetch your site, and nothing is uploaded; the analysis runs entirely in your browser. To audit a live page, copy its script tags or HTML (the network tab shows everything the page loads) and paste that. Remember the same limitation: scripts your own inline JavaScript loads at runtime are invisible unless you paste them too.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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