BuiltWith Alternatives: What Works for One Site vs. a Whole List

The best BuiltWith alternative depends on one thing: whether you check one website or a whole list.

In 2023, someone handed me 1,200 e-commerce domains and asked which ones ran Shopify. So I started with a browser extension. Sixty tabs later, I quit at row 74 with a headache.

One disclosure up front: CUFinder is the product I work on, so weigh my advice accordingly. Test anything here on your own 20 domains first.

Let’s get into it.

📌 TL;DR: One site → a free browser extension. A handful of sites → a free single-URL lookup page. A whole list → a bulk lookup or an enrichment add-on running on your column of domains. Building software → an API. Historical archives and market-share reports → the big technology-intelligence products, because that part they genuinely do best.

Why Do People Look for a BuiltWith Alternative?

Three reasons: price at list scale, a per-site workflow, and export limits.

Here’s the thing. A single lookup is cheap or free almost everywhere. But the moment you want 500 domains checked and exported, you’re in paid territory.

The second reason is workflow. Most checkers answer one question well: what runs on this one page? So your list of 500 quietly becomes 500 separate visits.

Then there’s export. Free tiers show you an answer on screen. They rarely hand you a file, and nobody can share a browser tab.

So what are people actually trying to do? Four jobs, and they need different tools:

• Check one prospect’s tech stack before a discovery call.
• Filter an existing prospect list by the technology each account runs.
• Monitor a stack over time, so you catch a migration while it’s happening.
• Feed detection into a product you’re building.

Only the first job stays free forever. That’s the honest shape of this market, and every section below assumes it.

How Do Website Technology Checkers Actually Work?

They read the public page and its responses, then match what they find against known patterns.

Nothing magic happens. Five signal types do almost all the work:

• Page HTML and script hosts. A theme path or a script loading from a marketing vendor’s domain is a fingerprint.
• HTTP response headers. Servers announce more than they mean to. MDN’s reference on the X-Powered-By header shows exactly how a backend hint leaks out.
• Cookie names. Platforms set cookies with recognisable names before you ever log in.
• DNS records. Mail and CDN records point straight at the vendors sitting behind them.
• JavaScript globals. Analytics and chat tools drop named objects onto the page.

You can watch all of this yourself. Open any site, press F12, and poke around the Network and Application panels. Google’s Chrome DevTools documentation walks through both. A checker simply automates that inspection and runs the results past a rule set.

Which brings me to the limit almost nobody writes down.

No checker can see your prospect’s database. Or their ERP, their internal admin tools, or anything server-side that leaves no public trace. If it doesn’t reach the browser, it doesn’t reach the report.

🔍 Did You Know? Technology detection reads only what a site shows the public: HTML, script hosts, headers, and cookies. The database behind the login page stays invisible to every checker on the market, including ours.

At web scale, though, detection gets impressively good. W3Techs runs a continuous survey of content management systems. WordPress sits far ahead of every other CMS it can identify. The Web Almanac’s CMS chapter applies the same fingerprinting across a huge public crawl. It lands in the same place.

So detection is dependable for popular, public technology. It thins out as the technology gets rarer or more private. Keep that in mind for every tool below, mine included.

The BuiltWith Alternatives I Tested, by Job

Every tool here exists to check what technology runs a website. The real difference is how many websites you can ask about at once.

So I judged them on four questions. Does it work on ONE domain or a COLUMN of domains? Is the free tier real, or a teaser? Can I export? And does it live where my list already lives?

No scoring rubric. No star ratings. Just those four questions, applied to six categories.

Browser Extensions

Best for: one prospect, right now, free.

Wappalyzer’s extension, WhatRuns, and a handful of similar add-ons sit in your browser toolbar. You land on a site, click the icon, and read the stack. For one check before a call, this is genuinely the right answer. And the best Wappalyzer alternative here is usually another extension, not a platform.

The catch: one tab at a time. No list output. Plus you’re granting an extension permission to read the pages you visit. So check what you’re installing.

And if you check one website a week? Stop here. Install a free extension, close this tab, and pay nobody anything. I mean that.

Free Single-URL Lookup Pages

Best for: a quick check without installing anything.

Plenty of sites give you a box, you paste a URL, and a stack comes back. BuiltWith itself has one. So do several smaller tools built purely as a free lookup page.

The catch: one URL per search, shallower detection than the paid tier, and no clean way to hand a list to a colleague. You copy. Then paste. Then repeat.

Open-Source and Self-Hosted Detectors

Best for: engineers who want to own the pipeline.

People search for this constantly, and almost nobody answers it honestly. Community detection projects live on GitHub. They’re open source, and you can run them on your own infrastructure against your own list.

The catch: you now maintain the detection rules. Platforms change their fingerprints quietly, and stale rules don’t throw errors. They just return confident, wrong answers. So budget engineering time, not zero.

Technology-Intelligence Platforms

Best for: historical data, market-share reporting, and buying lists of sites by technology.

BuiltWith and its direct rivals belong here, and for that job they’re genuinely good. Very few tools keep a years-deep archive of what a domain used to run.

The catch: the list-building side is the part that costs real money, and it’s priced for teams. Pricing moves constantly, so check the current plans yourself instead of trusting a number in a blog post. Including this one.

Technographic Data Providers and Enrichment Tools

Best for: a column of domains you already own.

This is CUFinder’s category, so mark it accordingly. Technographic just means data about the technology a company uses. Firmographic covers size, revenue, and industry, which is a separate company enrichment job. These tools take your existing list and return a stack per row. I compared the field properly in my rundown of technographic data providers.

The catch: coverage varies by segment and region, runs cost credits, and unmatched rows come back empty. Empty is the honest outcome. It’s still an empty cell.

APIs and DIY

Best for: putting detection inside your own product.

If the answer belongs in your app rather than your spreadsheet, you want an API. BuiltWith sells one, and so do most technographic providers, ours included. I put the API-first options head to head in our tech stack APIs compared guide.

The catch: you own the retries, the quotas, the rate limits, and the maintenance forever.

So here’s the decision rule I hand everyone who asks. Count your rows FIRST, then pick:

→ 1 row → browser extension → 10 rows → free lookup page → 100+ rows → bulk lookup or an add-on → inside your product → API

Which BuiltWith Alternative Is Actually Free?

Extensions and single-URL pages are free. Nothing that handles a whole list stays free forever.

That’s the entire answer, and I wish someone had said it to me in 2023.

Because free tools don’t cost nothing. They price your TIME instead. Twenty seconds per domain sounds harmless. But multiply it out: 1,200 domains at twenty seconds each is over six hours of clicking. That was my afternoon.

So a free BuiltWith alternative is real, and at low volume it’s the right call. Same story for a free Wappalyzer alternative. The extension does the job beautifully, one site at a time.

What about free credits? Every provider offers them, ours included. But let’s say the quiet part plainly: a free tier is a sample. It exists so you can test coverage on twenty of your own domains. That’s exactly what you should do with it.

And the open-source route? Free in licence, never free in hours. Someone still has to keep the rules current.

📌 Example: My 2023 file: 1,200 domains, 60 open tabs, quit at row 74. The same file the next quarter: one ranged run, then filtered down to Shopify in a single click.

How Do You Check a Whole List of Websites at Once?

Put the domains in one column, then run a tech-stack enrichment across your row range.

Disclosure again: CUFinder is the product I work on, so read this section with that in mind. Test it on your own 20 domains before you trust me. Here’s the exact loop:

1. Install the add-on. Grab the CUFinder add-on from the Google Workspace Marketplace. New to add-ons? Google’s help page explains how they install and where they show up.
2. Copy your API key. Open your CUFinder dashboard and copy the API key from there.
3. Enter the key in the add-on. Paste it once and you’re connected.
4. Pick the tech-stack service. Open the add-on from the Google Sheets menu. It opens as a right panel listing all the enrichment services. The one you want is find technology stack.
5. Map columns, set the range, run. Set the input column to your domains and the output column to wherever the stack should land. Then choose the row range (rows 2 to 1201 for my old file) and run it.

💡 Pro Tip: Clean your domains before any bulk run. No https://, no /pricing paths, no UTM tails. Just northwindceramics.com. Messy inputs are the number one reason rows come back empty.

Now the honest limits, before you spend a credit.

Detection is a snapshot, not a subscription record. Coverage varies by segment and by region. Unmatched rows come back empty rather than guessed, and every run costs credits. And we don’t sell the historical archive or market-share reporting. The big technology-intelligence products own that job.

One more input problem worth catching early. If your rows hold company NAMES instead of domains, convert them first. You can find each company’s website in the same sheet, then point the tech-stack run at that column.

Want the deeper mechanics? Manual checks, DevTools, filtering afterwards: I wrote a full bulk tech stack lookup guide for that. This page is about choosing. That one is about running it well.

A Worked Example: 5 Rows, Before and After

Say your sheet looks like this. Company names in column A, clean domains in column B, and an empty column C waiting for the stack:

	A	B	C
1	Company	Domain	Tech Stack
2	Northwind Ceramics	northwindceramics.com
3	Kestrel Outdoor	kestreloutdoor.com
4	Vellum Publishing	vellumpublishing.com
5	Ridgeline Fitness	ridgelinefitness.com
6	Saltbox Coffee	saltboxcoffee.com

Then you pick the tech-stack service in the panel, set the input to column B, the output to column C, and the range to rows 2 to 6. Run it. A moment later, the same sheet reads like this:

	A	B	C
1	Company	Domain	Tech Stack
2	Northwind Ceramics	northwindceramics.com	Shopify, Klaviyo
3	Kestrel Outdoor	kestreloutdoor.com	WordPress, GA4
4	Vellum Publishing	vellumpublishing.com	Webflow, HubSpot
5	Ridgeline Fitness	ridgelinefitness.com	Magento, Cloudflare
6	Saltbox Coffee	saltboxcoffee.com	Squarespace, Mailchimp

Now the step that turns a filled column into an actual list. Select your header row, open the Data menu, and choose Create a filter. Then click the little arrow on column C and filter for “Shopify”.

And there it is. Here that’s one row out of five. In a 1,200-row file, it’s the difference between a prospect list and a lost afternoon.

That filter beat is the whole reason to get this data into a spreadsheet. Segmenting accounts by stack is a technographic data in Google Sheets job, and it feeds your targeting directly. A prospect running a competing tool is a buying signal. And repeated stack patterns sharpen your ideal customer profile faster than any survey.

Two things usually happen next. You want more accounts like the Shopify ones, which means a find similar companies run on your best five. And you want a sharper angle for the outreach, which is where B2B technographic data earns its keep.

What Mistakes Should You Avoid When Checking Tech Stacks in Bulk?

The big ones: treating detection as proof of purchase, dirty inputs, stale data, and chasing free too far.

I’ve made most of these personally, so read this as a scar map.

• Treating detection as proof of purchase. A tag can easily outlive the contract. Someone cancelled the tool and left the script behind. So treat every hit as a hypothesis you confirm on the call.
• Enriching the header row. Start your range at row 2. Otherwise you’ll burn a credit asking what technology runs on a domain called “Domain”.
• Feeding URLs instead of domains. Paths and tracking parameters break matching. Strip everything back to the bare domain before you run anything.
• Assuming the backend is visible. It isn’t. If a prospect’s CRM or database matters to your pitch, ask them, because no website technology checker will tell you.
• Never refreshing. Stacks change all the time. Add a “checked on” date column beside the output, so future-you knows whether to trust column C or re-run it.
• Chasing free past the point where it pays. Once your hours cost more than the run, free stopped being free. Mine stopped at roughly row 74.

FAQ: BuiltWith Alternatives

Is BuiltWith free?

Partly. There’s a free single-site lookup, which covers the casual check just fine. But the lists, the historical data, and the exports are the paid product. Pricing and packaging move often, so check the current plans yourself rather than trusting a figure quoted in an article.

What is the best free BuiltWith alternative?

A browser extension, as long as you only check one site at a time. Wappalyzer’s extension and WhatRuns both sit in your toolbar and answer instantly. Free stops where lists begin, though. Once you need 200 domains checked and exported, every route costs money or hours.

Is there an open-source Wappalyzer alternative?

Yes. Community detection projects live on GitHub, and you can self-host them. You supply the infrastructure and you maintain the detection rules, which is the real cost. Platforms change their fingerprints without announcing it, and stale rules fail quietly instead of loudly. So plan for regular upkeep.

What is the difference between BuiltWith and Wappalyzer?

Both answer the same question and differ mostly in packaging. The BuiltWith vs Wappalyzer choice comes down to what each sells around the detection: extensions, lookups, list building, history, APIs. Those line-ups shift regularly, so compare the current plans yourself instead of an old comparison table.

Can I check the technology of a list of websites at once?

Yes, with a bulk lookup or an enrichment add-on running on a column of domains. Single-site checkers and browser extensions can’t do it, because they’re built for one tab. Anything list-shaped needs a tool that accepts a column, processes a row range, and writes results back.

How accurate are website technology checkers?

Accurate about public signals, blind to the backend, and always a snapshot. They catch popular front-end technology well: CMS, analytics, ecommerce platform, chat widgets. Anything server-side stays hidden. And they report what sits on the page today, which isn’t proof that anyone is still paying for it.

Can I use a BuiltWith alternative inside Google Sheets?

Yes. An add-on runs on your column of domains and writes the results straight back. You install it from the Marketplace, connect your API key, and pick the tech-stack service. Then set the input column, the output column, and the row range. The stack lands in your sheet, ready to filter.

Does BuiltWith have an API?

Yes, it sells one, and so do most technographic providers, ours included. If detection belongs inside your own product, an API is the right shape for the job. Compare coverage on your own sample of domains and the cost per lookup, not the marketing copy. Then budget for maintenance.

It’s Time to Pick the One That Fits Your Row Count

So count your rows first, then choose. One site → a free extension, and no guilt about closing this tab. A handful → a free lookup page. A real list → an add-on that runs on your column.

Picture the version I wanted back in 2023. That 1,200-domain file open. One ranged run going while I make coffee, column C filling itself, and a Shopify list waiting when I sit down. That’s a normal Tuesday now. It cost me one embarrassing afternoon to learn.

Tech stack is only one column, too. The whole data enrichment in Google Sheets hub covers what else belongs beside it: websites, revenue, contacts, funding. That’s B2B data enrichment in practice, one column at a time.

You’ve got this. Tell me in the comments: how many domains are sitting in your file right now?