Domain, WHOIS, IP and DNS data APIs and research tools.
Best for: Developers and analysts needing WHOIS and DNS data programmatically.
Top-rated in WHOIS ToolsDomains & DNS
From $30/mo (varies by queries)Free plan
WHOIS Tools
Look up who registered a domain, when it was created, and when it expires, including past WHOIS records.
Best WHOIS Tools
WHOIS tools retrieve available domain registration information, such as registrar, creation and expiry dates and nameservers. The buyer decision is whether one current RDAP or WHOIS result is sufficient or whether historical snapshots, reverse registrant searches and DNS changes need to be analyzed together. Some providers supply structured APIs for automated investigations; others favor direct browser lookups. Privacy redaction and incomplete historical capture limit what any of them can reveal about actual ownership. These choices are organized by investigation type, not an accuracy ranking.
By SEM Solutions Editorial Team. Researched from vendor documentation, not hands-on testing. Ordered by Overall Score. Checked October 17, 2026. How we research
Historical Registration APIs
WhoisXML API
Overall Score57/1003.8Editor RatingMarket Signal 43#1 of 5 in WHOIS Tools
WhoisXML API exposes structured WHOIS History and Reverse WHOIS services for integration into investigation tools. Analysts can retrieve previously captured registration records, while reverse searches connect domains that share specified registration identifiers. JSON and XML responses make the output easier to process than raw WHOIS text, which matters for scheduled checks or multi-domain research.
- WHOIS History API
- Reverse WHOIS API
- Structured API responses
- Best for
- Developers integrating registration snapshots and related-domain discovery into security or domain research systems.
- Consider
- The history reflects records collected by the provider rather than an exhaustive legal ownership ledger.
Domain Identity and Typosquats
WhoisFreaks
Overall Score56/1002.9Editor RatingMarket Signal 66#2 of 5 in WHOIS Tools
WhoisFreaks supports historical WHOIS queries alongside reverse searches based on registration fields. Its typosquatting service can surface registered variations of a brand domain, adding a protection use case beyond reading individual records. Downloadable datasets and API access allow teams to combine historical registration changes with broader domain monitoring rather than repeating manual browser searches.
- WHOIS History API
- Reverse WHOIS
- Domain Typosquats API
- Best for
- Brand protection teams examining related registrations and suspicious spelling variations of known domains.
- Consider
- Historical identity matches need verification because shared registrant details do not necessarily establish common ownership.
Infrastructure Relationship Research
DomainTools
Overall Score43/1002.2Editor RatingMarket Signal 55#3 of 5 in WHOIS Tools
DomainTools joins registration records with infrastructure-oriented research. An investigator can examine historical WHOIS information, then move to reverse registrant searches and hosting history to investigate other connected assets. Monitoring capabilities add change awareness after a domain is identified. Its value in this setting comes from following multiple lines of domain evidence rather than checking one expiry date.
- WHOIS History
- Reverse WHOIS
- Hosting History
- Best for
- Threat analysts tracing domains through registration identifiers, nameservers and historical hosting information.
- Consider
- Some historical and reverse-search capabilities require authenticated access beyond a public domain lookup.
DNS History Correlation
SecurityTrails
Overall Score42/1003.2Editor RatingMarket Signal 31#4 of 5 in WHOIS Tools
SecurityTrails provides historical DNS lookups alongside WHOIS information, allowing an analyst to examine changes in domain infrastructure and registration over time. Separate endpoints return earlier DNS record types and registration history. These can be cross-referenced to investigate changes of nameservers, mail infrastructure or address records without assuming that a DNS change proves a transfer of ownership.
- WHOIS history endpoint
- DNS record history
- REST API
- Best for
- Researchers investigating domain history alongside changes to mail, nameserver and hosting records.
- Consider
- WHOIS and historical DNS use different endpoints, so a combined timeline requires joining separate result sets.
Browser Registration Lookups
Who.is
Market Signal 62#5 of 5 in WHOIS Tools
Who.is offers direct domain lookups with access to RDAP information and an archive of past WHOIS records. Visitors can begin with a domain name and inspect available registration details before deciding whether to obtain a historical report. API documentation also covers programmatic access to selected information, but the browser workflow is easier to approach for individual research tasks.
- RDAP lookup
- Domain History Archive
- History reports
- Best for
- Website owners and domain researchers inspecting occasional registrations and available historical snapshots.
- Consider
- The initial lookup does not expose every detailed historical snapshot without using the archive-report workflow.
How to choose
- Separate current RDAP data from captured historical WHOIS records.
- Check reverse WHOIS support when linking domains by past registrant identifiers.
- Use DNS history when infrastructure movements matter as much as registration changes.
- Treat privacy-redacted data as unavailable, not evidence of the absence of ownership.
All WHOIS Tools (5)
Ranked by Overall Score: our Editor Rating and Market Signal, 50/50. Market Signal uses Ahrefs and Semrush data through September 2026, pulled October 6 to 13, 2026. How we score
Domain and IP intelligence APIs and databases covering WHOIS history, DNS and newly registered domains.
Best for: Threat intelligence and brand protection teams that need bulk WHOIS and DNS data piped into their own tools.
Domains & DNS
From $9 per month (annual billing), 5,000 API credits/mo
Domain and DNS intelligence, including WHOIS history.
Best for: Security and research teams investigating domains and their ownership history.
Domains & DNS
Historical DNS and WHOIS data via API.
Best for: Researchers needing historical DNS and WHOIS records.
Domains & DNS
From $500/mo
Domain lookup site for WHOIS, RDAP, DNS and IP records, with downloadable history reports.
Best for: Domain investors and investigators who need a quick registration lookup or a dated ownership timeline for a single domain.
Domains & DNS
Frequently Asked Questions
Is WHOIS the same as RDAP?⌄
WHOIS is the older domain registration query protocol. RDAP provides a more structured web-based approach to registration information. A current RDAP result and a historical WHOIS archive serve different purposes: the archive can preserve earlier public details, but cannot necessarily reconstruct records hidden by later redaction or missing collection periods.
Can historical WHOIS identify every previous domain owner?⌄
No. Providers may have recorded earlier registrant fields, including names or organizations that are no longer public. However, domain privacy services, inaccurate submissions and missing collection intervals limit completeness. A historical snapshot is evidence about a recorded registration at a given time, not necessarily proof of beneficial ownership.
Do any of the tools listed under WHOIS Tools have a free plan?⌄
Yes, WhoisXML API offers a free plan. Free tiers usually come with usage limits, so check whether they cover your volume before relying on them long-term.
Which tool listed under WHOIS Tools has the lowest starting price?⌄
Among the tools listed here whose main product is in this category and whose pricing we've verified, WhoisFreaks has the lowest listed starting price: $9 per month (annual billing), 5,000 API credits/mo. Starting price isn't the whole picture, so check what's included at that tier before deciding.