Home › Websites, SEO and tech › SSL Certificate Subdomain Finder
Find every subdomain of a domain with this SSL certificate finder, which searches public Certificate Transparency logs. Each hostname comes with first seen, last seen, expiry, issuer, certificate count and a freshness score. No login, no proxy.
| Field | Name | Required | What it does |
|---|---|---|---|
domains | Domains | no | Domains to look up, for example example.com. Subdomains of each domain are found from public certificate logs. A full URL also works. Leave empty to use the two example domains. |
hostnameContains | Hostname contains | no | Keep hostnames that contain at least one of these words (case-insensitive). Example: ["staging", "dev", "admin", "vpn"]. Leave empty for all hostnames. |
newWithinDays | First seen within (days) | no | Keep only hostnames whose first certificate was issued in the last N days. Good for spotting new services. 0 = no limit. |
statusFilter | Certificate status | no | active keeps hostnames whose newest certificate has not expired. expiring_soon keeps those that expire within 30 days. |
includeExpired | Include expired certificates | no | Turn off to read only certificates that are still valid. Hostnames that only ever had expired certificates are then missing. |
maxItems | Max hostnames | no | Stop after this many hostnames. You pay only for hostnames delivered. |
One row per result. These are the 18 fields declared in the actor's dataset schema (field list from the schema, not a sample run).
| Field | Type | Meaning |
|---|---|---|
subdomain | string | |
rootDomain | string | |
depth | integer | |
status | string | |
newScore | integer | |
firstSeenAt | string | |
lastSeenAt | string | |
expiresAt | string | |
daysSinceFirstSeen | integer | |
daysToExpiry | integer | |
certCount | integer | |
issuers | array | |
coveredByWildcard | boolean | |
latestCertId | string | |
certUrl | string | |
sourceUrl | string | |
source | string | |
checkedAt | string |
Public data only, no login. Fields a source does not publish come back empty rather than guessed. Coverage and freshness follow the underlying public source.
Pay on Apify, no subscription: $0.00047 per hostname (pay per event). The live price is on the actor page.
Disclosure: we build and maintain this actor.