How to Check if Someone Registered a Domain Similar to Yours

You own your domain. You've built your brand around it. But how do you know if someone else has quietly registered a domain that looks almost identical — and is using it to intercept your customers, send phishing emails, or clone your website?

The uncomfortable truth is that most businesses have no idea how many lookalike domains exist in the shadow of their brand. Attackers register them daily, and the registration process is cheap, fast, and largely anonymous. By the time you discover a lookalike domain through a customer complaint or a suspicious email report, the damage is usually already done.

This guide walks you through exactly how to check for domains similar to yours — from quick manual techniques to automated monitoring that catches threats in real time.

Why Lookalike Domains Are Dangerous

Before diving into the how, it's worth understanding the scale of the problem. Lookalike domains — also known as typosquats, homoglyph domains, or doppelgänger domains — are registered for a variety of malicious purposes:

• Phishing: Sending emails from a domain like yourband.com (missing the "r") to trick recipients into sharing credentials or making payments
• Website cloning: Hosting a near-identical copy of your site to harvest customer data or redirect purchases
• Traffic theft: Capturing visitors who mistype your URL and monetising them through ads or affiliate redirects
• Reputation damage: Hosting offensive or fraudulent content on a domain that looks like yours
• Supply chain attacks: Impersonating your company in communications with your partners, vendors, or employees

Research shows that the average brand has between 50 and 200+ lookalike domains registered against it at any given time. For well-known brands, that number can climb into the thousands. And you don't need to be a household name to be targeted — SMBs are increasingly the primary targets because attackers know they lack the resources to fight back.

Method 1: Manual WHOIS Lookups

The simplest starting point is a WHOIS lookup. WHOIS databases contain registration information for domain names, including when a domain was registered, who registered it (if not privacy-protected), and which registrar was used.

How to do it:

1. Brainstorm variations of your domain — common typos, missing letters, swapped characters, different TLDs (.net, .co, .org)
2. Search each variation using a WHOIS tool (like whois.domaintools.com or your terminal's whois command)
3. Check if the domain is registered and, if so, when it was created and by whom

Limitations: This approach is painfully slow and incomplete. A typical brand name has hundreds — sometimes thousands — of possible misspellings and variations. Checking them one at a time is impractical, and you'll inevitably miss the creative variations attackers actually use. Plus, WHOIS data increasingly shows "REDACTED FOR PRIVACY" thanks to GDPR-era registration policies, limiting its usefulness.

Method 2: Certificate Transparency Logs

Certificate Transparency (CT) logs are public records of every SSL/TLS certificate issued by a trusted Certificate Authority. Since most modern websites — including phishing sites — use HTTPS, CT logs are a surprisingly effective way to discover lookalike domains.

How to do it:

1. Visit a CT log search tool like crt.sh
2. Search for %.yourbrand% (using wildcards) to find certificates issued for domains containing your brand name
3. Review the results for suspicious domains you don't own

Why it works: When an attacker registers a lookalike domain and sets up a website (especially a phishing page), they almost always provision an SSL certificate to make the site appear legitimate. That certificate issuance gets logged in CT logs — often within minutes of the domain going active. This makes CT logs one of the fastest public signals that a lookalike domain has moved from "parked" to "weaponised."

Limitations: CT logs only capture domains with SSL certificates. They won't reveal parked domains, domains used only for email-based attacks, or domains that haven't yet been activated. You also need to check regularly — by the time you manually look, an attack may already be in progress.

Method 3: DNS Enumeration and Passive DNS

Passive DNS databases record historical DNS resolution data — essentially logging which domains resolved to which IP addresses over time. Tools like SecurityTrails, VirusTotal, and Farsight DNSDB allow you to search for domains similar to yours.

This approach can reveal lookalike domains that share hosting infrastructure with known malicious sites, or that were recently activated and pointed at web servers. It's more technical than WHOIS or CT log searches, but it provides deeper visibility into the infrastructure behind a suspicious domain.

Limitations: Passive DNS requires technical expertise to use effectively. The data can be overwhelming, and interpreting whether a similar domain is malicious or benign requires context that raw DNS records don't provide.

Method 4: Google Dorking

A quick and surprisingly effective technique is to use Google's advanced search operators to find websites impersonating your brand.

Try searches like:

• intitle:"Your Brand Name" -site:yourdomain.com — finds pages using your brand name that aren't on your site
• "Your Brand Name" login -site:yourdomain.com — specifically targets fake login pages
• site:yourbrand.net OR site:yourbrand.co OR site:yourbrand.org — checks whether TLD variants have active websites

Limitations: Google only indexes a fraction of the web, and newly created phishing sites may not appear in search results for hours or days. This method catches established threats but misses new ones — exactly the window when they're most dangerous.

Method 5: Automated Domain Monitoring

The methods above are useful for spot checks, but they share a fundamental flaw: they're reactive. By the time you manually discover a lookalike domain, it may have been active for days or weeks — long enough to launch a phishing campaign, defraud customers, or damage your reputation.

Automated domain monitoring solves this by continuously scanning new domain registrations and matching them against your brand in real time. Instead of you searching for threats, the threats come to you — as alerts, the moment they appear.

What good automated monitoring looks like:

• Real-time scanning: New registrations detected within hours, not days
• Comprehensive variation coverage: Not just typos — homoglyphs, TLD variations, combosquats, and character substitutions
• Risk assessment: Distinguishing between a parked domain and one actively hosting phishing content or sending email
• Actionable alerts: Clear notifications with enough context to decide whether to act immediately or monitor further

How DoppelDown Makes This Effortless

DoppelDown automates the entire lookalike domain detection process. Instead of cobbling together WHOIS lookups, CT log searches, and Google dorks, you enter your domain once and DoppelDown handles the rest:

• Continuous monitoring across all major TLDs and registration feeds
• Detection of all variation types — typosquats, homoglyphs, combosquats, TLD swaps, and more
• Intelligent risk scoring that analyses DNS, hosting, email configuration, and active content to separate real threats from dormant registrations
• Instant alerts so you can respond before an attack reaches your customers

The manual methods described in this guide work — but they don't scale, and they don't run while you sleep. DoppelDown does.

Start Checking Today

Every day you're not monitoring for lookalike domains is a day an attacker could be using one against you. The good news: getting started takes less than five minutes.

Sign up for DoppelDown free — no credit card required — and see exactly how many domains similar to yours already exist. You might be surprised by what you find. And you'll definitely be glad you looked.

Want to understand the broader landscape first? Read our guide on how to protect your brand from domain squatting and phishing in 2026 or explore DoppelDown's pricing plans for teams and growing businesses.