Domain Availability API - Check If a Domain Is Registered
Queries RDAP (the modern successor to WHOIS) for a domain and reports whether it is registered. Returns available: true when RDAP responds 404 and registered: true with the registrar name when a record exists. Works across all gTLDs and most ccTLDs supported by public RDAP servers.
Code examples
curl -X POST https://api.botoi.com/v1/domain/availability \
-H "Content-Type: application/json" \
-d '{"domain":"botoi.com"}'When to use this API
Domain-name suggestion tools
When a user types a product name, generate variant domain candidates (add -app, -hq, -io) and call this endpoint in parallel. Show only the ones with available: true.
Brand monitoring and defensive registration
Check typo-squatted variants of your brand domain on a schedule. Get notified the moment a lookalike registers so you can take action through UDRP or a cease-and-desist.
Bulk availability checks for portfolio resellers
Feed a list of candidate domains through this endpoint from a batch job. Combine available and registrar fields with your own valuation rules to surface expired or dropped domains worth acquiring.
Frequently asked questions
How does this differ from a WHOIS lookup?
Does available: true guarantee I can register the domain?
Which TLDs are supported?
Is the registrar field always present?
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