How to Find a Website’s Subdomains — and Which Ones Bring Search Traffic
Finding subdomains serves two needs: security audits want every subdomain, SEO wants the ones with search traffic. The methods for each, and real data showing how Shopify uses subdomains for its app store, help center and community.
Finding subdomains serves two needs: security audits want every subdomain, SEO wants the ones with search traffic. The methods for each, and real data showing how Shopify uses subdomains for its app store, help center and community.
People look up a site’s subdomains for two reasons: security or operations audits, which need as many subdomains as possible, and SEO or competitor research, which cares about the subdomains that rank on Google and how much traffic they bring. The methods differ.
1. Two Kinds of Methods
| Goal | Method | What you see |
|---|---|---|
| Security / operations | Certificate transparency logs, DNS records, a site:example.com search | As many subdomains as possible, including internal systems with no traffic |
| SEO / competitor research | Data on subdomains with organic rankings | Only subdomains with traffic, with estimated traffic and ranking keyword counts |
The subdomain finder is built on search ranking data and lists only subdomains with organic Google traffic. It is for understanding a competitor’s traffic structure, not for a security asset inventory.
2. Real Example: shopify.com
On 9 October 2026 we checked shopify.com (United States) with the subdomain finder: 32 subdomains have organic search traffic. Sorted by estimated monthly traffic:
| Subdomain | Est. monthly traffic | Ranking keywords |
|---|---|---|
| shopify.com | 2,214,692 | 246,008 |
| apps.shopify.com | 427,430 | 21,049 |
| help.shopify.com | 321,359 | 9,018 |
| community.shopify.com | 76,712 | 18,360 |
| themes.shopify.com | 32,171 | 3,667 |
- The app store and help center together bring about 750,000 monthly visits, a third of the main site: they absorb a huge number of "how do I do X on Shopify" searches.
- The community ranks for twice as many keywords as the help center (18,360) with a quarter of the traffic: forums cover a long tail of questions, each with small volume.
- For competitor research, this shows Shopify’s SEO is not just the main-site blog but also apps, themes and user-generated content.
3. Subdomain or Subdirectory?
Google says it can crawl and rank either structure. In practice the choice is mostly technical and organisational: separate systems (help center, community, app store) are easier to deploy on subdomains, while most sites keep blogs in a subdirectory so the content shares the main site’s brand and link signals.
Subdomain Finder
List a site’s subdomains with organic Google traffic, with estimated traffic and ranking keyword counts. One free check a day.