Query 4.5 Billion Subdomains.
Instantly.

The world's largest subdomain intelligence API. One GET request. Every subdomain ever observed.

Enter a root domain like example.com

4.5B+ subdomains indexedUpdated daily<100ms response time
Get Free API KeyView API Docs
terminal
$ curl https://subdomains.jsmon.sh/api/domain/tesla.com \
    -H 'Api-Key: YOUR_API_KEY'

{
  "domain": "tesla.com",
  "total": 4521,
  "subdomains": [
    "mail.tesla.com",
    "api.tesla.com",
    "vpn.tesla.com",
    ...
  ]
}

Used by security researchers, red teams, and bug bounty hunters worldwide

4.5B+

Subdomains indexed

<100ms

Average response time

24/7

Continuous data collection

Three steps. That's it.

From sign-up to subdomain data in under a minute.

01

Sign up

Create your free account. No credit card required.

02

Get your API key

One key. One endpoint. Unlimited possibilities.

03

Query any domain

GET request returns every known subdomain. Paginated. Fast.

Works with everything

One endpoint. Every language.

curl -s "https://subdomains.jsmon.sh/api/domain/example.com" \
  -H "Api-Key: YOUR_API_KEY" | jq .

Simple, transparent pricing

Start free. Scale when you're ready.

Free

$0forever
  • 3 queries per day
  • Up to 100 results per query
  • Community support
Get Started
Most Popular

Pro

$20/ month
  • 5,000 queries per month
  • Up to 10,000 results per query
  • No rate limiting
  • Priority support
Start Pro

Max

$100/ month
  • 50,000 queries per month
  • Up to 10,000 results per query
  • No rate limiting
  • Priority support

10x the queries, 5x the price

Start Max

Enterprise

Custom
  • Full commercial data access
  • For ASM vendors, MSSPs, and security providers
  • Bulk data exports
  • Dedicated support
  • SLA guarantees
Contact Sales

Subdomains are just the surface.

Found interesting subdomains? Jsmon's AI-powered Attack Surface Management platform goes deeper — exposed secrets, vulnerable APIs, misconfigurations, and continuous monitoring. See what's hiding in your attack surface.

Explore Jsmon

Questions? Answers.

Our infrastructure continuously collects subdomain data from certificate transparency logs, DNS records, web crawling, and other OSINT sources. The database is updated daily.

The database is updated continuously. Most subdomains are observed within 24-48 hours of appearing in public sources.

Absolutely. Many of our users are bug bounty hunters and security researchers. The Free plan gives you 3 queries per day to get started.

This product is a focused subdomain lookup API. Jsmon is a full Attack Surface Management platform that includes subdomain enumeration plus vulnerability detection, secret scanning, JS analysis, and continuous monitoring.

Not yet, but it's coming. Contact [email protected] for custom billing arrangements.

Free accounts are limited to 3 queries per day. Pro and Max plans have no rate limits.