Wappalyzer Alternatives (2026): Free, Open-Source and Paid Options Compared

Most people searching for a Wappalyzer alternative are reacting to something specific: in August 2023, Wappalyzer went closed-source. The GitHub repository was taken down, the npm package was deprecated, and the community-contributed fingerprint database — until then GPL-3.0 licensed — was absorbed into the commercial product.

If you are looking for a replacement because of that, this guide covers the open-source continuations, the free tools, and the paid platforms. Every price and figure below was read from the vendor's own page in July 2026 and is linked to its source. Where a vendor does not publish a number, this guide says so instead of estimating one.

A note on what this guide does not contain

Nearly every "Wappalyzer alternatives" article ranks tools by detection accuracy. Almost none of them publish a method, a sample, or a date. One page currently ranking for this term promises "Tested on 50 Real Sites" in its title tag and contains no test data at all.

An earlier version of this article did the same thing, and it was wrong to. It contained accuracy tables presented as head-to-head test results. Those tables have been removed, along with the testing narrative around them, because they were not backed by a test anyone ran. Removing them is the honest correction, and inventing replacement numbers would repeat the original error.

What replaces them is more useful anyway: an explanation of why each tool's detection method determines what it can and cannot see, and a benchmark procedure you can run against your own sites in an afternoon. Your results will be more relevant to your work than anyone else's would be.

Two myths worth clearing up first

"Wappalyzer's extension went paid." It did not. The browser extension still performs technology detection for free with no account required. What is capped is the account — the free plan includes 50 technology lookups per month — and the API. (Wappalyzer pricing, July 2026)

"Wappalyzer was acquired by Dun & Bradstreet." This appears on at least one page currently ranking for this keyword, and there is no completed acquisition on record. Wappalyzer remains independent. The confusion may stem from an unrelated deal: Dun & Bradstreet itself was acquired by Clearlake Capital in 2025.

How technology detection actually works

Every difference in accuracy between these tools traces back to one architectural decision: where the tool looks. Understanding this is more useful than any ranking, because it tells you in advance which tool will fail on which technology.

There are four broad approaches.

Rendered-DOM inspection (browser extensions). The tool runs in your browser and examines the page after JavaScript has executed. Wappalyzer's extension inspects "HTML, scripts, cookies, network requests, and certificates on the pages you visit, looking for unique technology fingerprints" (Wappalyzer extension FAQ). This catches client-side frameworks that inject themselves at runtime — React, Vue, Next.js — which a raw HTML fetch can miss entirely.

Server-side crawling (databases). The vendor crawls the web on a schedule and stores what it finds, so you query a database rather than a live page. BuiltWith describes it plainly: "We index the Internet in the same way that Google does to power their search engine. We don't get data from any third parties" (BuiltWith FAQ). This is what makes historical data and "list every site using X" queries possible — and it is also why the data reflects the last crawl rather than the current moment.

Header, DNS and certificate signals. Some technologies never appear in page markup at all. A Server: or X-Powered-By response header, an MX record, an SPF record, or a TLS certificate issuer can each identify infrastructure that is invisible to any amount of DOM inspection. You can check these yourself — SEOmator's free HTTP header checker shows a site's response headers, and the hosting checker resolves DNS and IP records to a provider.

Inference from external signals. Job postings, public code repositories, and financial filings can indicate internal technology. This is the least reliable category and the hardest to verify.

Why this matters more than a percentage

A browser extension cannot detect your database. Not because it is a weak product, but because your database emits no client-side signal. PostgreSQL, Redis, and internal service frameworks do not announce themselves in the DOM. Any tool that claims strong backend detection is either reading headers and DNS, inferring from job listings, or guessing.

The reverse is also true. A scheduled crawler that fetches raw HTML without executing JavaScript will under-report client-side frameworks — the same asymmetry Googlebot faces between its crawl and render waves, which is precisely why this matters for SEO work and not just prospecting.

Two further complications apply to every tool on this list:

• Production builds strip fingerprints. Minification, bundling, and tree-shaking remove the version strings and comment blocks many signatures rely on. A well-optimized site is genuinely harder to fingerprint.
• A missing detection is not the same as an absent technology. Every one of these tools reports what it recognizes, not what is there. Treat a negative result as "not detected," never as "not present."

Free and open-source Wappalyzer alternatives

This is the category most guides skip, and it is what a large share of people searching for alternatives actually want.

The community forks

When Wappalyzer closed its repository in 2023, the last GPL-3.0 fingerprint set was already public, and several projects continued from it. enthec/webappanalyzer describes itself as "a continuation of the iconic Wappalyzer that went private in August 2023" and maintains the technology definitions. dochne/wappalyzer is another continuation of the same lineage.

One caveat applies to this whole category, and it is rarely mentioned: most free technology detectors — including several marketed as independent products — run forks of Wappalyzer's pre-2023 ruleset. They therefore inherit its blind spots exactly. If Wappalyzer's signature set could not see a technology in 2023, a fork of it generally still cannot. Swapping to a fork changes the license and the price, not the detection ceiling.

Check the commit history before relying on one. A fork that has kept pace with new frameworks is genuinely useful; one that was archived in 2024 is a snapshot of a three-year-old web.

WhatWeb

WhatWeb is a long-standing open-source command-line scanner with its own independent signature set rather than a Wappalyzer fork. It suits automation and bulk scanning, and it is a different tool in character from a browser extension — you will be reading terminal output, not a popup panel. For anyone comparing "WhatWeb vs Wappalyzer," the honest summary is that they are built for different jobs: one for scripted scanning, the other for point-and-click research while browsing.

Browser-based lookups

If you would rather not install anything, a hosted lookup answers the one-off "what is this site built with" question without an extension. SEOmator publishes a free website technology checker that does this — it is our own tool, and it is listed here on the same terms as everything else: it handles single-site lookups and does not offer bulk export or historical data.

Commercial Wappalyzer alternatives

BuiltWith

BuiltWith is the closest thing to an opposite of Wappalyzer's extension: a scheduled server-side crawl feeding a queryable database.

Its strongest verifiable differentiator is history. BuiltWith publishes "18+ years of technology history" and includes it from the entry plan, with the Domain API supporting date-range queries. Neither Wappalyzer nor WhatRuns publishes a comparable historical claim. If you need to know when a site adopted or dropped something — a platform migration, an analytics swap, a CDN change — this is the differentiator that matters.

For SEO work specifically, that time dimension is the useful part. A competitor's replatforming date gives you a before-and-after boundary for their ranking history that no live-detection tool can reconstruct.

On coverage figures: BuiltWith's own homepage counter reads 123,451+ technologies and its plans page states data from 491.9 million domains. Both are live counters and will drift, which is why they are cited here with a date.

What BuiltWith does not publish: API pricing (it requires sign-in), and any crawl frequency. The widely repeated claim that BuiltWith "crawls daily" does not appear in its own documentation — it originates in third-party write-ups. Treat crawl recency as unknown unless you test it.

WhatRuns

WhatRuns is free and requires no account. It also offers a forward-looking "follow this site" alert that notifies you when a followed site's stack changes — worth distinguishing from historical data, because it only accumulates from the moment you start following.

A correction: earlier versions of this article, and many others still ranking, list a WhatRuns "Premium" tier at $9/month. That figure could not be verified. The whatruns.com/pricing page loads but contains no plan table or price of any kind, and the homepage presents the product as free. The $9 figure appears to originate in third-party listicles, several of which confuse WhatRuns with WhatRunsWhere, an unrelated advertising-intelligence product with entirely different pricing. If you have seen $9/month quoted for WhatRuns, that is likely where it came from.

WhatRuns publishes no explanation of how it matches signatures, so this guide makes no claim about its detection mechanism beyond the fact that it ships as an extension. Practitioner opinion is mixed; some find it thin compared to Wappalyzer's extension. Since it is free, testing it costs nothing but a few minutes.

ZoomInfo

ZoomInfo is a different category of product. Technology detection is one input into a platform built around contact data, intent signals, and CRM enrichment — you would not buy it to identify a CMS.

On pricing: ZoomInfo publishes no prices. The "~$15,000/year" figure that circulates in comparison articles — including a previous version of this one — is not a ZoomInfo figure and should not be treated as one. Procurement data from Vendr puts the median contract meaningfully higher, around $31,875. The honest answer is that you will not know your price until you speak to their sales team, and it will depend on seats, credits, and modules.

On the "95% accuracy" claim: this one is real but narrower than it is usually quoted. It is a contractual guarantee in ZoomInfo's licence terms that 95% of contacts work at the company stated. It explicitly does not cover email deliverability, phone-number accuracy, or job titles. Quoting it as general data accuracy overstates it.

On contact volume: ZoomInfo's own published figures conflict across pages, so this guide omits a contact count rather than picking the most flattering one.

SimilarTech

SimilarTech's distinguishing feature is its relationship with Similarweb's traffic dataset — technology detection alongside traffic estimates and audience data, which is genuinely useful context when profiling a competitor.

Its 10-year historical claim is plausible on its face; the company has operated since 2012.

Proceed with some caution on the current state of the product. As of July 2026 the pricing page returns a 404 and the www subdomain does not resolve, though the main site is up. Any specific price you find quoted for SimilarTech — the $290/month figure appears in several articles — comes from a page that no longer exists. Confirm current terms directly before planning around it.

Newer entrants

TechnologyChecker.io markets historical technology data bundled with contact information, at published prices of Free, $89/month (Pro) and $249/month (Scale) — notably more transparent pricing than ZoomInfo or SimilarTech currently offer.

It is, however, very new: the domain was registered in August 2025, making the product roughly eleven months old at the time of writing, and its Chrome extension currently shows 5.0 stars from 3 ratings. A 5.0 average from three reviews is not comparable to WhatRuns' 4.2 from 828, and presenting those side by side without the counts would be misleading.

Its marketing describes a 20-year historical dataset. Its own documentation indicates that recent years come from its own crawls while prior years are reconstructed from public web archives such as Common Crawl — which is a legitimate technique, but it is archive reconstruction rather than two decades of first-party observation, and an eleven-month-old company could not have the latter. Its published technology count also differs between its homepage and its Chrome Web Store listing.

None of this makes it a bad tool; it may well be a good one. It means its claims are not yet independently verifiable, and it does not belong in the same tier as platforms with a decade or more of public track record. Evaluate it on a trial against your own sites.

Pricing: what you will actually pay in 2026

All figures read from vendor pricing pages in July 2026. Anything a vendor does not publish is marked as such rather than estimated.

Three things this table corrects, because they are widely repeated:

1. Wappalyzer has no "Starter" plan. The ladder is Free / Pro / Business / Enterprise. If you have read that 5,000 lookups cost $149/month, the current figure is $250/month at the Pro tier.
2. BuiltWith's entry price is $295/month, not $199. And the $995 plan is named Team; BuiltWith publishes no plan called "Business."
3. API credits expire after 60 days on every paid Wappalyzer tier. This is published on their pricing page and rarely mentioned in comparisons, but it matters if your usage is seasonal — credits bought for a quarterly research push do not roll forward indefinitely.

Cost per lookup

At Wappalyzer's published rates, Pro works out to $0.05 per lookup ($250 ÷ 5,000) and Business to $0.0225 ($450 ÷ 20,000). Cost per lookup falls as volume rises, which is the normal shape — but only counts if you actually use the allowance before the credits expire.

BuiltWith is not directly comparable, since its plans meter technologies and reports rather than lookups.

How to benchmark detection accuracy yourself

Rather than trusting anyone's accuracy table, including one on this page, run this. It takes an afternoon and produces results that are actually about your work.

1. Build a ground-truth set of 20–30 sites you can verify. This is the part that makes the exercise valid, and the reason most published benchmarks are worthless — you must know the right answer independently. Good sources: your own properties, current and former clients, sites whose engineering blogs document their stack, and sites whose public repositories reveal it.

2. Include deliberately hard cases. A benchmark of ten WordPress sites tells you nothing, because everything detects WordPress. Include at least a few of each:

• A JavaScript-heavy SPA (tests rendered-DOM vs. raw-fetch detection)
• A headless CMS with a decoupled front end
• A site behind a CDN or reverse proxy (tests whether headers are obscured)
• A site on a niche or regional platform
• A recently migrated site (tests data freshness)

3. Record three things separately, not one. Every comparison article collapses these, and they are different properties:

• Coverage — did it name the technology at all?
• Accuracy — was the name correct and specific? "React" when the answer is "Next.js" is a partial credit, not a hit.
• Freshness — does it reflect the current stack or a stale crawl? Your recently migrated site answers this.

4. Note false positives, not just misses. A tool that reports six technologies a site does not use is worse than one that reports three fewer and is right. Most benchmarks only count hits, which rewards over-reporting.

5. Test the categories you actually care about. If you evaluate stacks for technical SEO, weight CMS, CDN, tag manager, and JS framework detection heavily and ignore CRM detection. If you prospect, weight the reverse.

The result will not be publishable as a universal ranking — a 25-site sample is not one, and neither was any table it replaces. It will be a reliable answer to the only question that matters: which tool is right most often on sites like yours.

Which alternative fits your workflow

You want free, and you want it now. WhatRuns or the Wappalyzer extension. Both are free; the extension's detection remains free without an account.

You want open-source or self-hosted. Start with the maintained community forks, checking commit recency first. Use WhatWeb if you need CLI and automation.

You need historical data. BuiltWith, at $295/month. Its 18+ years of history is the strongest verifiable differentiator of any tool here, and it is available from the entry tier.

You need bulk lookups or an API. Wappalyzer Pro at $250/month, or BuiltWith — noting that BuiltWith does not publish API pricing and Wappalyzer's credits expire after 60 days.

You need technographics inside a sales platform. ZoomInfo, if enterprise budget is available and you have use for the rest of the platform.

You want traffic context alongside the stack. SimilarTech, after confirming current pricing directly.

For SEO and technical audit work specifically

If you are here for SEO rather than prospecting, the tool matters less than what you do with the output:

• Framework detection is a rendering diagnostic. Finding React or Next.js tells you to check whether content exists in the raw HTML or only after hydration — which determines what Googlebot indexes on the first pass.
• CDN and header detection is a performance lead. Response headers reveal caching behavior and compression; you can inspect them directly with a header checker.
• Stack changes over time explain ranking changes. A CMS migration in a competitor's history is often the missing explanation for a traffic shift.
• Third-party script inventory is Core Web Vitals triage. The tag managers and analytics tools a detector lists are the same scripts inflating load time.

For any of these, start by identifying who your actual SERP competitors are — profiling the stack of a site you do not compete with is wasted effort.

Frequently asked questions

Is Wappalyzer still free?

Yes. The browser extension detects technologies for free with no account. A free account adds 50 lookups per month. Paid plans start at $250/month (Pro) for 5,000 lookups and API access. (Pricing, July 2026)

Why did Wappalyzer go closed-source?

Wappalyzer moved its previously GPL-3.0 fingerprint database into its commercial product in August 2023, deleting the public repository and deprecating the npm package. The company has not published a detailed rationale. Community forks continue from the last open release.

What is the best free Wappalyzer alternative?

For zero-cost browser lookups, WhatRuns, or Wappalyzer's own extension. For self-hosting or automation, a maintained community fork or WhatWeb. Note that most free detectors derive from Wappalyzer's pre-2023 signature set and share its blind spots.

What is the difference between WhatWeb and Wappalyzer?

WhatWeb is an open-source command-line scanner with its own signature set, suited to automation and bulk scanning. Wappalyzer is a commercial product delivered primarily as a browser extension for interactive research. Different tools for different jobs.

Why do these tools disagree about the same website?

Because they look in different places. A browser extension reads the rendered DOM; a database tool reports its last crawl; header- and DNS-based lookups see infrastructure that never appears in markup. Disagreement usually reflects different methods rather than one tool being broken.

Can any of them reliably detect backend technology?

Not from client-side signals alone. Databases, server frameworks, and internal services generally emit nothing a browser can read. Tools that do better here are reading HTTP headers, DNS records and certificates, or inferring from sources like job postings. Treat all backend detection as lower-confidence than front-end detection, whatever the vendor claims.

How current is the data?

It depends entirely on method. Browser extensions read the live page, so they are current by construction. Database products reflect their last crawl — and BuiltWith, for one, does not publish a crawl frequency, so recency is best established by testing a site you know recently changed.

The short version

Wappalyzer going closed-source in 2023 is why this search exists, but the extension is still free and still good at what it does. Most people looking for an alternative need one of three specific things it does not provide: historical data (BuiltWith), bulk API access at lower cost (compare Wappalyzer Pro against BuiltWith directly), or an open-source implementation they control (the community forks).

Before committing to any paid plan, run the benchmark procedure above on your own sites. Every tool here has a free tier or a trial, and twenty-five sites you can verify will tell you more than any published comparison — this one included.