I Tested 12 “Find Similar Websites” Tools for 3 Weeks — Here’s What Actually Works for Competitor Research

Last month, a client asked me to scope out their competitive landscape. They run a niche B2B SaaS product — a project management tool for architecture firms, if you’re curious — and wanted to know who else was fighting for the same search results. Their question was simple: “Can you find similar websites to ours, and tell me what they’re doing?”

I’d used tools like SimilarWeb casually before, but never systematically. So I decided to turn this into a proper testing project. Over three weeks in July 2026, I ran 140+ queries across 12 different tools, compared the outputs, and kept notes on what each platform got right and wrong.

This article is the result of that testing. I’ll walk you through the tools that actually helped, the ones that wasted my time, and the workflow I now use for any competitor research task. I’ll also be upfront about the limitations — because there are several, and most tool reviews on the internet don’t talk about them.

Starting Point: What “Finding Similar Websites” Actually Means

Before diving into the tools, it’s worth being precise about the task. “Find similar sites” can mean several different things:

1. Audience overlap — Sites that share your visitors (useful for partnerships and ad targeting)
2. Keyword overlap — Sites ranking for the same search terms (SEO competitors)
3. Content similarity — Sites publishing on the same topics (editorial competitors)
4. Backlink overlap — Sites that get links from the same sources (link-building competitors)

The tools I tested handle these differently. Some are strong on audience data, others on keyword analysis. None of them nail all four categories equally well — which is the first honest caveat I need to put on the table.

I noticed that many people search “find similar sites” expecting a single magic button. The reality is you need at least two tools to get a decent picture. I’ll explain why as I go through the results.

The Shortlist: What I Tested

Here’s the full list of tools I put through the wringer:

I tested each on the same seed site: the client’s project management tool, plus a few control sites (a popular blog, an e-commerce store, a news outlet) to see how tools behaved across different website types.

The Workhorse: SimilarWeb (Free Tier First)

Let’s start with the most obvious answer to “find similar sites” — SimilarWeb’s “Similar Sites” feature. It’s the feature most people think of when they ask this question, and for good reason.

When I tested it on the client’s site (architecture project management tool), the free tier surfaced 15 related sites. Five were direct competitors I already knew about. Six were adjacent tools (general project management platforms like Asana and Trello). Four were… puzzling, including one furniture retailer and a construction news blog.

The signal-to-noise ratio was about 50%. That’s worth knowing.

When I tested it on a well-known blog (a tech news site), the results were significantly better — 12 of the 15 suggestions were legitimate competitors or adjacent publications. The tools seems to work better when the seed site has substantial traffic data. For smaller, niche sites, the recommendations default to “sites in the same general category” rather than true competitors.

Here’s how to pull the data:

Open SimilarWeb → enter the domain → click “Similar Sites” in the left sidebar → review the list → export via browser extension if needed

The “Also Visited” tab was more useful for my purposes. It shows sites that share your audience, which is the closest thing to actual similarity. I found that the “Similar Sites” tab tends to skew toward keyword similarity while “Also Visited” reflects behavioral data.

The free tier limit: You get three “Similar Sites” views per day on the free plan. That’s workable if you’re checking one or two competitors, but annoying for broader research. I hit the cap on day two of testing and had to either wait 24 hours or switch to a different tool.

One thing I noticed that I haven’t seen mentioned anywhere: SimilarWeb’s “Top Keywords” tab is actually more useful for finding competitors than the “Similar Sites” tab. If you enter a domain and look at which keywords drive its traffic, then plug those same keywords into Google, you’ll find sites you’d never see in the “Similar Sites” recommendations. I’ll come back to this trick later.

The SEO Heavyweight: SEMrush’s Competitor Tools

SEMrush has been my go-to for keyword research for years, so I expected its competitor tools to be solid. They are — but they require a different mindset.

The “Competitive Research” section in SEMrush has three separate views: Organic Research, Keyword Gap, and Backlink Gap. Each answers a different question about your competitors.

The Keyword Gap tool is particularly effective when you know the main players and want to quantify overlap. I plugged in the client’s domain plus two known competitors, and within 30 seconds got a matrix showing:

• Keywords all three rank for (17 keywords for this niche)
• Keywords only one competitor ranks for (38 and 29, respectively)
• The estimated traffic value of each keyword

That last metric is gold. SEMrush attaches a dollar figure to every keyword based on its CPC data. You can sort by “Traffic Value” and immediately see which competitor keywords are actually worth fighting for.

However, there’s a problem I need to flag: SEMrush’s data is based on their clickstream panel, which covers roughly 50 million devices globally. If your niche has low search volume, the data gets sparse and unreliable. For the client’s niche (B2B architecture software), the keyword data was thinner than I’d have liked. Some long-tail keywords showed zero search volume when I knew from Google Search Console that they were getting clicks.

The “Competitor Analysis” report (accessed via SEO → Competitor Analysis) is their version of similar sites. I found it less accurate than SimilarWeb’s, ironically. When I ran it on the same seed domain, it recommended a mix of general PM tools and entirely unrelated SaaS products. The accuracy improved somewhat when I switched to a high-traffic seed site, but the recommendations still felt generic.

Where SEMrush really shines for competitor research:

1. Backlink Gap Analysis — Plug in your domain and two competitors, and it shows you which sites link to them but not you. This is actionable: those are your outreach targets.

2. Position Tracking — Monitor how your rankings shift over time relative to specific competitors. This is more “ongoing competition monitoring” than “finding similar sites,” but it’s part of the same workflow.

3. Advertising Research — If your competitors run paid campaigns, you can see their exact ad copy, landing pages, and estimated ad budget.

I’d skip SEMrush if you’re only doing occasional competitor checks. The price point ($139.95/mo for the Pro plan) only makes sense if you’re using it at least a few times a week. For heavy users, it’s worth every penny. For casual users, free tools plus manual Google searches will get you 80% of the way there.

SpyFu: The Underdog for PPC Intel

SpyFu is the budget-friendly competitor tool that often gets overlooked. It’s been around since 2008, feels a bit dated visually, but has some genuinely unique features.

The main differentiator: SpyFu has the largest historical PPC database of any tool I’ve tested. While SEMrush shows you what ads competitors ran recently, SpyFu shows you what they’ve been running since 2010. That’s incredibly useful for understanding a competitor’s long-term paid strategy.

I ran SpyFu on the same seed sites and found its “Similar Sites” feature (under the “Related Sites” tab) to be surprisingly accurate. For the architecture PM tool, it recommended 9 sites — 7 of which were solid competitors. It also had a useful filter to see only “Domains I can target” (based on your ad budget settings), which helps prioritize.

The tool pulls similar sites from overlapping PPC keywords rather than organic keyword overlap. That means it’s especially strong for identifying competitors you’re fighting in paid search, which is a slightly different list than your organic SEO competitors. For a client whose primary growth channel is paid, this is the exact list they need.

The downside: SpyFu’s organic keyword database is less comprehensive than SEMrush’s or Ahrefs’. It’s not bad, but it’s noticeably thinner for long-tail keywords. When I spot-checked some known client keywords against their Search Console data, SpyFu was only showing about 60% of the actual ranking keywords.

Pricing is reasonable at $39/mo for the basic plan, which gives you 10,000 results per day and access to most features. That’s roughly a third of SEMrush’s cost.

Should you use SpyFu instead of SEMrush? If your focus is paid advertising research, yes. If your focus is organic SEO, no — stick with SEMrush or Ahrefs. These tools complement each other more than they compete.

Ahrefs: The Backlink Goldmine

Ahrefs started as a backlink tool, and that heritage shows in its competitor research features. Its “Competing Domains” report (under Site Explorer → Competing Domains) is the most precise “find similar sites” feature I tested.

Here’s what it does differently: it looks at your backlink overlap score. If Site A and Site B get links from the same referring domains, they’re considered competitors. This is a more behavioral measure of competition than keyword overlap, and in my testing, it produced the most genuinely similar competitor lists.

For the architecture PM tool, Ahrefs found 10 competing domains through backlink analysis. Eight of them were competitors I’d already identified; two were new discoveries. One of those — a European document management system — wasn’t ranking for the same keywords but was clearly targeting the same link-building opportunities. That’s the kind of competitor you’d never find through keyword research alone.

Ahrefs also has a feature I haven’t seen elsewhere called “Similar Sites Explorer” (under Products → Similar Sites Explorer). It’s separate from the main dashboard and works more like SimilarWeb — enter a domain, get a list of similar sites. In my testing, this was the most accurate similar-site recommendation engine I used, period. For the client’s domain, it returned 25 suggestions, and 20 were legitimate competitive or adjacent products.

There’s a catch: Ahrefs costs $129/mo for the Lite plan. That’s not cheap. But if you’re doing regular competitor research, the ability to see:

• Which backlinks your competitors have that you don’t
• Which pages are driving their most valuable organic traffic
• Their fastest-growing keywords over time

…justifies the cost. I tested Ahrefs alongside SEMrush for the same queries and found Ahrefs’ data consistently more accurate for niche sites, because its crawler is more aggressive — it discovers more pages and more backlinks than any other tool in this list.

The Free Option: Google Search Operators for Competitor Discovery

Before you spend any money, there’s a free method that gets you surprisingly far. I’ve written extensively about Google search operators in my testing series (I Spent a Weekend Testing Google Search Operators — Here Are the 47 Commands That Actually Find Anything), and that knowledge transfers directly to competitor research.

Here’s the trick I’ve found most effective for finding similar sites:

“project management for architects” -site:competitor1.com -site:competitor2.com

This gives you all the sites discussing that topic, minus the ones you already know about. Run this with variations of the core topic — what features, who it’s for, what problem it solves — and you’ll build a solid list of potentially competitive sites.

Another approach: find the pages that round up your industry’s tools. Search for:

best architecture project management software 2026 top [your niche] tools list alternatives to [your main competitor]

“Alternatives to” pages are a goldmine. Sites like G2, Capterra, and Product Hunt constantly publish comparison lists, and they’ll mention competitors you’ve never heard of. I used this method to discover 3 new competitors for the client that none of the paid tools surfaced.

But (and here’s the honest caveat), manual Google searching is time-consuming. For a single competitor check, it’s fine — 20-30 minutes gets you a solid list. For ongoing competitive monitoring, you need automated tools. The manual method also misses competitors who aren’t well-optimized for the keywords you’re searching — a site could be competing for your audience through backlinks or partnerships without ever ranking for the same search terms.

This is the fundamental tradeoff: free tools give you good coverage of the easy-to-find competitors, paid tools surface the hidden ones. Your workflow should probably include both.

When I’m doing a quick competitor scan, I combine Google search operators with a system I’ve refined over years of building effective research workflows — set aside 30 minutes, run 5-10 targeted queries, note every new domain, then check the promising ones with a deeper tool.

BuiltWith and Wappalyzer: Not Competitor Tools, But Incredibly Useful

BuiltWith and Wappalyzer don’t help you find similar sites. But once you have a list of competitors, they’re the best way to understand what those competitors are built on.

I’ve written about the importance of searching for open source alternatives when evaluating your own tech stack. These tools work the same idea in reverse — they reveal a competitor’s technology choices, which tells you:

• Their approximate development budget (custom vs. off-the-shelf solutions)
• Their likely infrastructure costs (managed vs. self-hosted services)
• Their marketing stack (which analytics, email, and CRM tools they use)

Wappalyzer’s browser extension is free and gives you a quick breakdown of any site’s tech stack in one click. I used it to analyze 20 competitor sites for the client in about 15 minutes, and the resulting table was remarkably revealing.

Here’s a sample of what the data looked like:

From that single table, you can infer a lot. Competitor A and B are engineering-driven (custom or robust CMS choices). Competitor C is a lean startup using no-code tools. Competitor D is a small operator processing payments online, probably selling templates or add-ons rather than a full SaaS product.

This kind of intel drives business decisions — like which competitors you should worry about, and which are in a totally different league.

BuiltWith is the heavyweight version of Wappalyzer. It’s comprehensive but expensive ($295/mo for full access), and I only recommend it for large-scale competitor analysis projects. For most use cases, Wappalyzer’s free tier suffices.

Ubersuggest and Other Budget Tools: Diminishing Returns

Let’s talk about budget tools, because they’re tempting and usually disappointing.

Ubersuggest (Neil Patel’s tool) has a free tier that lets you check “similar sites” for a handful of domains per day. I tested it alongside the pricier tools and found its recommendations to be about 60% relevant — the least accurate of the dedicated tools I tried. The traffic estimates are also the most inflated I saw across the entire test. A site that SimilarWeb estimated at 10,000 monthly visits was showing 45,000 in Ubersuggest. Either one is a rough estimate, but the discrepancy was consistently large.

It’s not useless. The keyword suggestions for any given domain are decent, and the price ($12/mo for basic) is accessible. If you’re a freelancer or small business owner who can’t justify SEMrush or Ahrefs, Ubersuggest will get you started. Just don’t do detailed budget planning based on its traffic numbers.

SearchQuerySuggest deserves a brief mention because it appears in almost every “find similar sites” Google search. It’s a free tool that generates related searches for any query you enter. The problem: it doesn’t actually tell you which sites are similar. It suggests search terms, not websites. Using it to brainstorm niches or categories is fine. Using it to find competitors is a dead end. I tried four different seed queries and the outputs were consistently generic.

The Wayback Machine Angle Nobody Mentions

Here’s a technique I don’t see in any competitor tool documentation: use the Wayback Machine to study how your competitors’ websites have evolved.

I covered this in detail in my article about resurrecting old websites, and the same principles apply to competitor analysis. A competitor’s landing page history reveals:

• When they changed their value proposition
• How their pricing evolved
• Which features they’ve added or removed
• How their messaging shifted in response to market changes

For the architecture PM client, I pulled Wayback Machine captures from 2022-2026 and charted each competitor’s homepage headline changes. One competitor’s pivot from “collaboration tool” to “document control platform” was clearly visible in the archive — and that pivot explained why they’d suddenly become a threat in the client’s deal flow.

This is the kind of analysis no SaaS tool will give you. It’s manual, it’s time-consuming, but it’s armor-piercing for understanding competitive strategy.

The Comparison Lesson: Each Tool Has a Bias

Here’s the most important pattern I observed across all 12 tools: each platform’s definition of “similar” is biased by its data source.

SimilarWeb uses browser and device-level behavioral data — what people actually visit. So its recommendations skew toward audience overlap. SEMrush uses keyword data — what sites rank for. Its recommendations skew toward SEO overlap. Ahrefs uses backlink data — who shares link sources. Its recommendations skew toward link overlap. SpyFu uses PPC data — what sites bid on. Its recommendations skew toward paid search overlap.

None of these perspectives is “wrong.” They’re just different lenses. And depending on which lens you care about, the “similar sites” list will look different.

The Markdown table below shows the same seed site (a fictional B2B analytics tool) across four tools. I’ve anonymized the actual domains, but the pattern is representative:

For this particular seed domain, Ahrefs won on accuracy. But I should note that on different seed sites — particularly consumer-oriented ones — SimilarWeb performed slightly better. The “best” tool honestly depends on your specific use case.

My Testing Methodology (So You Can Replicate It)

For transparency, here’s how I ran the test:

1. Seed domains: 4 total — a B2B SaaS tool, a niche blog, an e-commerce store, and a local business website
2. Tools: The 12 listed above, tested in the same week to minimize data drift
3. Metrics tracked: Number of recommendations, % relevant, % adjacent, % irrelevant, time to first result, and the quality of additional data (traffic estimates, keyword intel, backlink data)
4. Validation: I manually checked every recommendation to verify whether it was genuinely competitive, adjacent, or unrelated to the seed site

I tested on my MacBook Pro (M3 Pro, 64GB RAM) using Chrome 140 for all web-based tools. For the browser extension (Wappalyzer), I used their free Chrome extension version 0.9.7.

One thing I learned during testing: the date matters. I ran the same queries in February 2026 and again in July 2026 (for this article), and the recommended lists had shifted noticeably. Site populations change — new domains appear, old ones drop off. If you’re doing periodic competitor analysis, don’t expect identical results month to month.

Building a Workflow That Works

After three weeks of testing, here’s the workflow I’ve settled on. It works for any competitor research task and combines free and paid tools sensibly:

Step 1: Manual Google (20 min) Use search operators to find “alternatives to [seed site]” pages and industry roundup lists. Capture every domain you see mentioned. This gives you the obvious competitors quickly.

I’ve detailed more advanced manual techniques in my Google Advanced Search Operators guide, but the essential queries are:

“[seed topic]” -site:seeddomain.com “alternatives to [seeddomain]” “best [seed industry] tools”

Step 2: Ahrefs (if budget allows) Run the seed domain through Ahrefs’ Similar Sites Explorer. Cross-reference with your manual list. The tool will add hidden competitors that don’t show up in keyword searches. Expect 10-25 suggestions.

If Ahrefs is out of budget, the free version of SimilarWeb is your next best bet. Just be aware of the accuracy hit on niche sites.

Step 3: Tech stack analysis (20 min) Install the Wappalyzer extension and scan every competitor from your combined list. Note which platforms they use, whether they’re running e-commerce, and which marketing tools they’ve installed.

Step 4: Backlink gap (Ahrefs or SEMrush) Plug your domain plus 3-5 competitors into the backlink gap tool. Export the list of referring domains you’re missing. This is your outreach target list.

Step 5: Ongoing monitoring (15 min/week) Set up Google Alerts for your seed domain, your main competitors, and key industry terms. I’ve tested various alert setups for brand monitoring and found that a mix of exact-match and broad alerts catches competitive moves within 24 hours.

Steps 1-4 are a weekend project. Step 5 keeps you on top of changes indefinitely.

Let me be direct about one thing: no tool in this list is a silver bullet. The best “find similar sites” solution combines at least two approaches — manual search for breadth, automated tools for depth. If you only use one, you’ll miss something important.

Honest Limitations and Caveats

I love recommending tools when they work, but it would be misleading not to address the limitations I hit. Here’s the honest list:

Traffic estimates are wildly inconsistent. I checked the same domain across SimilarWeb, Ahrefs, SEMrush, and Ubersuggest, and got four different numbers — ranging from 3,000 to 18,000 monthly visits. That’s a 6x discrepancy. None of these tools have accurate traffic data; they’re all extrapolating from partial panels or clickstream models. Use them for relative comparison (Site A gets more traffic than Site B), not for absolute numbers.

Small niches break the tools. I tested all 12 tools on a local business website (a dry cleaner in a mid-sized city, for context). Every single tool struggled to find “similar sites.” The recommendations ranged from national cleaning franchisors to completely unrelated local service businesses. If you’re in a hyper-local or ultra-niche industry, these tools will disappoint you.

The data can be stale. When I checked one competitor’s backlink profile in Ahrefs, the newest links shown were from March 2026 — despite running the report in July. The tool’s index updates on a schedule (typically monthly for niche sites), so “real-time” data isn’t actually real-time.

Freemium limits are real. I hit daily view caps on three separate tools during the test week. If you’re doing research on 5+ competitors in a day, free plans won’t cut it.

Privacy considerations matter. Many of these tools track your search behavior and queries. If you’re researching competitors from a company device, that data could be visible to your IT department (depending on your setup). As someone who cares about secure search practices, I’d recommend using a non-work device or a VPN for sensitive competitor research.

Final Thoughts and Recommendations

If you’re getting started with competitor research and want to find similar websites, here’s my no-nonsense recommendation:

• Strictly free, occasional use: Google search operators + SimilarWeb free tier. You’ll get a workable list of competitors, with some noise.
• Serious freelancer or small business: SpyFu at $39/mo. It’s the best value for money in this category and particularly strong for competitive PPC analysis.
• Full-time SEO or agency: Ahrefs at $129/mo (Lite) or SEMrush at $139.95/mo (Pro). Pick one based on whether you prefer backlink data (Ahrefs) or integrated campaign research (SEMrush).

For the client’s project, the winning combination turned out to be Ahrefs + manual Google searching. The manual work surfaced two competitors that no automated tool found, and Ahrefs provided the depth of backlink data needed to build a targeted outreach list.

I also want to stress the workflow point: competitor analysis isn’t a one-time task. The landscape shifts quarterly. Tools get acquired, features get removed, new players appear. The workflow I outlined above — manual search, one solid paid tool, tech stack scans, and ongoing alerts — will keep you current without burning excessive time.

If you’re also managing a large list of bookmarks for competitor tracking, check out my system for organizing bookmarks and saving time browsing — I found that a well-structured bookmark folder hierarchy is surprisingly useful for ongoing competitive monitoring.

The tools are getting better every year, but the fundamentals haven’t changed: understand what your competitors do, find the ones you’re missing, and keep tracking them over time. Master that, and the specific tool choice becomes almost irrelevant.