99.99%
Uptime
Production-ready endpoints are designed for 99.99% uptime and documented status handling.
Category
Security
Endpoints
1
Key Features
8
Frequently Asked Questions
5
Used by people at amazing companies
Trust signals before you integrate
Transparent docs, authenticated requests, and visible reliability details make it easier to evaluate DomScan before you ship.
OpenAPI
API artifacts
OpenAPI, Swagger, Postman, CLI, SDK, and MCP links are one click away.
API keys
Protected access
Authenticated endpoints use API keys with clear credit costs before you call them.
10,000
Free allowance
Start with 10,000 monthly credits and upgrade only when usage grows.
What this API helps you ship
Use this page as a production brief: endpoints, examples, response shape, and the workflow pieces needed to plug DomScan into your own product.
Embed domain checks, DNS intelligence, risk signals, or enrichment into onboarding, search, and internal tools.
Replace repeated manual lookups with scheduled jobs, alerting, and reproducible investigation steps.
Use predictable fields, documented status codes, and credit costs instead of scraping provider pages.
Feed agents, dashboards, SOAR playbooks, and CRMs through OpenAPI, SDK, Postman, or MCP.
Integration workflow
A simple path from first request to repeatable production usage.
Authenticate once
Send your API key with the documented header and keep requests consistent across services.
Query with examples
Start from the curl and HTTP samples, then map the parameters into your application code.
Operate and monitor
Use status codes, credit costs, and response fields to build retries, logs, and alerts.
Developer kit
Jump from this page into machine-readable docs, request collections, SDKs, or agent tooling.
OpenAPI schema
Generate clients or inspect every request and response shape.
Postman collectionImport ready-made requests for manual testing and team handoff.
SDKs and CLIUse maintained packages and command-line workflows instead of writing boilerplate.
MCP integrationExpose domain intelligence to AI agents and internal assistant workflows.
Parameters and response map
Scan the inputs, output fields, and status codes before wiring the endpoint into your client.
Parameter
domain
Example Response
domainsubdomainssummarysummary.total_foundsummary.returnedsummary.verified_countsummary.unverified_countsummary.sources_usedmetameta.query_time_msmeta.cached
HTTP Status Codes
200202400402429500502503504
Endpoints
GET
/v1/subdomains
domain
Trust signals before you integrate
Transparent docs, authenticated requests, and visible reliability details make it easier to evaluate DomScan before you ship.
Uptime
API artifacts
OpenAPI, Swagger, Postman, CLI, SDK, and MCP links are one click away.
API keys
Protected access
Authenticated endpoints use API keys with clear credit costs before you call them.
Free allowance
Sign Up for Free
Start with 10,000 monthly credits and upgrade only when usage grows.
Active
Example Request
Start from the curl and HTTP samples, then map the parameters into your application code.
Key Features
CT Log Discovery
Find subdomains from Certificate Transparency logs.
Cache-first Polling
Use prefer_cache=1 to avoid blocking on CT logs; cold misses return 202 and queue a refresh.
Passive Reconnaissance
Non-intrusive discovery without touching target servers.
Asset Discovery
Find forgotten or shadow IT subdomains.
Security Assessment
Map attack surface for penetration testing.
Historical Data
Discover subdomains from historical certificate records.
Fast Results
Cached results return immediately; cold cache-only misses include Retry-After guidance.
API Integration
Easy to integrate into security workflows and tools.
Example Request
curl -H "X-API-Key: $DOMSCAN_API_KEY" "https://domscan.net/v1/subdomains?domain=example.com"Example Response
{
"domain": "example.com",
"subdomains": [
{
"name": "api.example.com",
"source": "ct",
"first_seen": "2026-01-18T09:24:00Z",
"verified": false,
"dns_records": null
},
{
"name": "www.example.com",
"source": "ct",
"first_seen": "2025-11-04T14:10:00Z",
"verified": false,
"dns_records": null
}
],
"summary": {
"total_found": 2,
"returned": 2,
"verified_count": 0,
"unverified_count": 2,
"sources_used": ["crtsh"]
},
"meta": {
"query_time_ms": 842,
"cached": false
}
}Frequently Asked Questions
How do you find subdomains?
We query public Certificate Transparency sources such as crt.sh and normalize the certificate names into deduplicated subdomain results. Optional DNS verification can confirm which returned hosts resolve.
Is this legal?
Yes. We use publicly available data sources (CT logs are public by design, DNS is public). We do not perform active scanning or brute-force enumeration.
How complete is the discovery?
CT logs capture hostnames that have appeared on public certificates. This is strong passive coverage, but it will not reveal internal-only hosts or names that never used public TLS.
What does a 202 response mean?
A 202 means no cached subdomain result was ready for a cache-only request. We queued a background refresh, returned Retry-After, and charged 0 credits for that pending response.
Can this find vulnerabilities?
Subdomain discovery is the first step in security assessment. Finding forgotten dev/staging subdomains or shadow IT often reveals security weaknesses.
Related Tools & Resources
HTTP Status Codes
We document the HTTP status codes you should handle so you can distinguish successful responses, auth issues, credits, rate limits, missing data, and upstream failures.
OK
200
Request successful
Accepted
202
Cache-only subdomain miss accepted for background refresh. No credits are charged; retry after the Retry-After delay.
Bad Request
400
Invalid parameters
Payment Required
402
Not enough credits to run this request.
Too Many Requests
429
Rate limit exceeded
Server Error
500
Internal error
Bad Gateway
502
Upstream RDAP error
Service Unavailable
503
Upstream service unavailable or temporarily rate limited.
Gateway Timeout
504
Upstream lookup timed out.
Discover Subdomains