What Are Website Spy Tools?
"Website spy tools" is a broad term, and the right tool depends entirely on what you want to learn about a competitor's website. In practice, website spy tools fall into three distinct categories, and confusing them is the most common reason marketers pick the wrong software:
- Traffic & audience spy tools — estimate a site's visits, traffic sources, top pages and audience demographics.
- Technology & SEO spy tools — reveal the tech stack, plugins, keywords and backlinks a website uses.
- Ad intelligence (ad spy) tools — show the actual ads, creatives and landing pages a website is running to acquire customers.
If your goal is to reverse-engineer how a competitor acquires paid traffic — which is what most performance marketers and affiliates actually want — you need the third category. That is where a dedicated ad spy tool like Anstrex fits, and where generic "website traffic" tools cannot help.
The 3 Categories of Website Spy Tools (and the Best of Each)
1. Traffic & audience intelligence
These tools estimate how much traffic a website gets and where it comes from. SimilarWeb and Semrush are the best-known options. Use them to size a competitor's overall audience and channel mix (search, social, referral, paid). They are estimates, not exact numbers, and they do not show you the actual ad creatives behind paid traffic.
2. Technology & SEO footprint
BuiltWith and Wappalyzer reveal a site's technology stack — CMS, analytics, pixels, checkout and apps. Ahrefs and Semrush cover the SEO side: keywords, rankings and backlinks. These answer "how is this site built and how does it rank," not "what ads is it running."
3. Ad intelligence (the ad spy layer)
To see the ads a website actually runs, you need an ad spy tool. Anstrex covers native (Taboola, Outbrain, Revcontent, MGID), TikTok, push and pop; AdSpy and PowerAdSpy cover Facebook and Instagram; SpyFu covers Google Search. This is the category that shows creatives, headlines and full landing pages — the blueprint you can model your own campaigns on.
How to Spy on a Competitor Website's Ads
Once you know a competitor is buying paid traffic, an ad spy tool lets you see exactly what they run. Using Anstrex as the example:
- Search by advertiser domain: enter the competitor's website to pull their ad history across native, push and pop.
- Sort by campaign duration: long-running ads are the profitable ones worth studying.
- Study the creative and funnel: review the image, headline and offer, then download the full landing page with the ripper.
- Expand cross-channel: check whether the same offer is running on TikTok or native to spot channels the competitor has not saturated yet.
This is the practical core of "spying on a website" for anyone who cares about paid acquisition. For the full tool-by-tool breakdown, see the best ad spy tools comparison, or the native ads spy tool guide for Taboola and Outbrain specifically.
Which Website Spy Tool Should You Use?
- Want traffic estimates? Use SimilarWeb or Semrush.
- Want the tech stack or backlinks? Use BuiltWith, Wappalyzer or Ahrefs.
- Want the actual ads and landing pages driving their sales? Use an ad spy tool — Anstrex for native/TikTok/push/pop, AdSpy or PowerAdSpy for Meta, SpyFu for Google Search.
Most serious competitor research combines two: one traffic/SEO tool to size the opportunity, and one ad spy tool to reverse-engineer the paid funnel. If paid acquisition is your priority, start with the ad intelligence layer.
Evidence Notes
Checked against public sources: the advertised category, coverage and starting price of each tool named at time of writing.
Not independently tested: database sizes, data freshness and support quality of third-party tools.
Reader should verify: current pricing and plan details directly on each vendor's website before subscribing.
Last checked: August 2026.