API reference

Base URL

https://rdapapi.io/api/v1

Authentication

Authorization: Bearer YOUR_API_KEY

Keys live on the dashboard once you are subscribed.

Domain

Look up one domain, or up to 10 in a single call with the bulk endpoint.

Domain Lookup

GET/domain/{domain}

Registration data for a domain, over RDAP or, where a TLD has none, WHOIS.

Parameters

domainstringRequiredpath: The domain name to look up
followbooleanquery default false: Also fetch contacts from the registrar. Needed for .com and .net (thin registries); elsewhere it only fills gaps. Slower when uncached.
whoisbooleanquery default true: Set false to refuse the WHOIS fallback, so a TLD with no RDAP server returns 404 not_supported. See WHOIS fallback.

Status codes

200: Successful lookup
400: Invalid domain name format
404: No data for this domain. Only not_found means it may be free; not_registrable, domain_reserved and not_supported never do. See Errors.
502: The registry failed to answer (lookup_failed), or we did (bad_gateway). See Errors.
503: Upstream RDAP server temporarily rate-limited

Plus the common errors.

Response fields (44)

domainstringgoogle.com
Queried domain name (lowercase)
unicode_namestring | null
Unicode form as the registry sends it; some send the ASCII name
handlestring | null2138514_DOMAIN_COM-VRSN
Registry-assigned handle
statusstring[]["client delete prohibited","client transfer prohibited","server delete prohibited"]
Always lowercase and space-separated — a registry sending clientDeleteProhibited arrives as client delete prohibited. Values we do not recognise pass through unchanged. See Terminology → Status values.
- namestring | nullMarkMonitor Inc.
- iana_idstring | null292
- abuse_emailstring | null[email protected]
- abuse_phonestring | null+12086851750
  Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
- urlstring | nullhttp://www.markmonitor.com
- registeredstring | null1997-09-15T04:00:00Z
- expiresstring | null2028-09-14T04:00:00Z
- updatedstring | null2019-09-09T15:39:04Z
nameserversstring[]["ns1.google.com","ns2.google.com","ns3.google.com","ns4.google.com"]
List of nameserver hostnames
dnssecboolean | nullfalse
Whether the delegation is signed. null where the registry publishes no DNSSEC status, as .tr, .gg and .nc do not.
Contact entities keyed by role (registrant, administrative, technical, billing, abuse). Keys depend on what the registry/registrar provides. See Terminology → Entity roles for what each role means.
- One contact. Any field may be null or withheld.
  - handlestring | nullORG-ARAD1-AP
    Registry handle for this entity
  - namestring | null
  - organizationstring | nullGoogle LLC
  - emailstring | null
  - phonestring | null
    Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
  - addressstring | null
  - contact_urlstring | nullhttps://domaincontact.registrar.cloudflare.com/example.com
    Where a server withholds email and publishes a web form instead, this carries it.
  - country_codestring | nullUS
    ISO 3166-1 alpha-2 country code from the address. Unlike the text fields, a redaction placeholder here is dropped to null rather than passed through — it is not a country code.
- administrativeContact may be absent
  One contact. Any field may be null or withheld.
- technicalContact may be absent
  One contact. Any field may be null or withheld.
- billingContact may be absent
  One contact. Any field may be null or withheld.
- abuseContact may be absent
  One contact. Any field may be null or withheld.
Fields the server declared withheld, at the same path as in the record. See Redaction.
- handlestringremoval may be absent
  removal, emptyValue, partialValue or replacementValue; see Redaction.
- registrarobject may be absent
  Claims about the top-level registrar object. Domain lookups only.
- entitiesobject may be absent
  Claims keyed by contact role, then by field within that contact.
Where the answer came from, and how it was served.
- serverstring | nullrdap.verisign.com
  Host that answered, as /tlds reports it (usable as ?server=). May be null on old cached records.
- sourcestringrdap
  Which protocol answered. Always rdap except on domain lookups, where a TLD with no RDAP server is answered over WHOIS.
- rdap_serverstringhttps://rdap.verisign.com/com/v1/ may be absent
  Base URL of the RDAP server, present only when source is rdap. Use server for the host that answered, or raw_rdap_url for the exact endpoint queried.
- raw_rdap_urlstringhttps://rdap.verisign.com/com/v1/domain/google.com may be absent
  Direct URL to the raw RDAP response. Absent when source is whois, which has no URL form, or when a stored snapshot answered.
- cachedbooleantrue may be absent
  Whether the response was served from cache. Omitted from the partial meta of a failed bulk entry.
- cache_expiresstring2026-02-18T15:30:00Z may be absent
  Cache expiration time (ISO 8601). Omitted from the partial meta of a failed bulk entry.
- followedboolean may be absent
  Whether the registrar's RDAP server was queried for richer data. Only present when ?follow=true is used and source is rdap.
- registrar_rdap_serverstring | null may be absent
  URL of the registrar's RDAP record the registry linked to. Only present when ?follow=true is used.
- follow_errorstring | null may be absent
  Error message if the follow request failed. Only present when ?follow=true is used and the request fails.

Request

curl https://rdapapi.io/api/v1/domain/google.com \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.domain("google.com");

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.domain("google.com")

Response

{
    "domain": "google.com",
    "unicode_name": null,
    "handle": "2138514_DOMAIN_COM-VRSN",
    "status": [
        "client delete prohibited",
        "client transfer prohibited",
        "client update prohibited",
        "server delete prohibited",
        "server transfer prohibited",
        "server update prohibited"
    ],
    "registrar": {
        "name": "MarkMonitor Inc.",
        "iana_id": "292",
        "abuse_email": "[email protected]",
        "abuse_phone": "+12086851750",
        "url": "http://www.markmonitor.com"
    },
    "dates": {
        "registered": "1997-09-15T04:00:00Z",
        "expires": "2028-09-14T04:00:00Z",
        "updated": "2019-09-09T15:39:04Z"
    },
    "nameservers": [
        "ns1.google.com",
        "ns2.google.com",
        "ns3.google.com",
        "ns4.google.com"
    ],
    "dnssec": false,
    "entities": {},
    "meta": {
        "server": "rdap.verisign.com",
        "source": "rdap",
        "rdap_server": "https://rdap.verisign.com/com/v1/",
        "raw_rdap_url": "https://rdap.verisign.com/com/v1/domain/google.com",
        "cached": true,
        "cache_expires": "2026-02-18T15:30:00Z"
    }
}

{
    "domain": "google.com",
    "unicode_name": null,
    "handle": "2138514_DOMAIN_COM-VRSN",
    "status": [
        "client delete prohibited",
        "client transfer prohibited",
        "client update prohibited",
        "server delete prohibited",
        "server transfer prohibited",
        "server update prohibited"
    ],
    "registrar": {
        "name": "MarkMonitor Inc.",
        "iana_id": "292",
        "abuse_email": "[email protected]",
        "abuse_phone": "+12086851750",
        "url": "http://www.markmonitor.com"
    },
    "dates": {
        "registered": "1997-09-15T04:00:00Z",
        "expires": "2028-09-14T04:00:00Z",
        "updated": "2019-09-09T15:39:04Z"
    },
    "nameservers": [
        "ns1.google.com",
        "ns2.google.com",
        "ns3.google.com",
        "ns4.google.com"
    ],
    "dnssec": false,
    "entities": {
        "registrant": {
            "handle": null,
            "name": "REDACTED REGISTRANT",
            "organization": "REDACTED FOR PRIVACY",
            "email": "redacted for privacy",
            "phone": "REDACTED FOR PRIVACY",
            "address": "REDACTED FOR PRIVACY\nREDACTED FOR PRIVACY\nCA\nREDACTED FOR PRIVACY",
            "contact_url": "https://domains.markmonitor.com/whois/contact/google.com",
            "country_code": "US"
        },
        "technical": {
            "handle": null,
            "name": null,
            "organization": null,
            "email": null,
            "phone": null,
            "address": null,
            "contact_url": "https://domains.markmonitor.com/whois/contact/google.com",
            "country_code": null
        }
    },
    "meta": {
        "server": "rdap.verisign.com",
        "source": "rdap",
        "rdap_server": "https://rdap.verisign.com/com/v1/",
        "raw_rdap_url": "https://rdap.verisign.com/com/v1/domain/google.com",
        "cached": false,
        "cache_expires": "2026-02-18T15:30:00Z",
        "followed": true,
        "registrar_rdap_server": "https://rdap.markmonitor.com/rdap/domain/GOOGLE.COM"
    }
}

{
    "domain": "google.it",
    "unicode_name": null,
    "handle": null,
    "status": [
        "active"
    ],
    "registrar": {
        "name": "MarkMonitor International Limited",
        "iana_id": null,
        "abuse_email": null,
        "abuse_phone": null,
        "url": "https://www.markmonitor.com/"
    },
    "dates": {
        "registered": "1999-12-10T00:00:00Z",
        "expires": "2027-04-21T00:00:00Z",
        "updated": "2026-06-09T23:13:34Z"
    },
    "nameservers": [
        "ns1.google.com",
        "ns2.google.com"
    ],
    "dnssec": false,
    "entities": {
        "registrant": {
            "handle": null,
            "name": null,
            "organization": "Google Ireland Holdings Unlimited Company",
            "email": null,
            "phone": null,
            "address": "70 Sir John Rogerson's Quay, Dublin, 2, Dublin, IE",
            "contact_url": null,
            "country_code": "IE"
        }
    },
    "meta": {
        "server": "whois.nic.it",
        "source": "whois",
        "cached": false,
        "cache_expires": "2026-02-18T15:30:00Z"
    }
}

Bulk Domain Lookup

POST/domains/bulk

Up to 10 domains in one request (Pro and Business). The batch answers 200 even when some domains fail: check each entry's status and error. Each domain is billed like a single lookup. Uncached batches can take 5–15 seconds.

Parameters

domainsstring[]Requiredbody: List of domain names to look up (max 10). Duplicates are collapsed, ignoring case, so you can get back fewer results than you sent.
followbooleanbody default false: Merge in the contacts held by the registrar, for every domain in the request.
whoisbooleanbody default true: Set false to refuse the WHOIS fallback, for every domain in the request.

Status codes

200: Bulk lookup results. Always returns 200 even if individual domains fail. Check each result's status field for per-domain success/failure.
403: No active subscription or plan upgrade required
422: Validation error

Plus the common errors.

Response fields (57)

Ordered list of results matching input order (deduplicated)
- domainstringgoogle.com
  The queried domain name
- statusstringsuccess
  Whether this individual lookup succeeded
- Domain lookup data (present when status is "success")
  - domainstringgoogle.com
    Queried domain name (lowercase)
  - unicode_namestring | null
    Unicode form as the registry sends it; some send the ASCII name
  - handlestring | null2138514_DOMAIN_COM-VRSN
    Registry-assigned handle
  - statusstring[]["client delete prohibited","client transfer prohibited","server delete prohibited"]
    Always lowercase and space-separated — a registry sending clientDeleteProhibited arrives as client delete prohibited. Values we do not recognise pass through unchanged. See Terminology → Status values.
  - nameserversstring[]["ns1.google.com","ns2.google.com","ns3.google.com","ns4.google.com"]
    List of nameserver hostnames
  - dnssecboolean | nullfalse
    Whether the delegation is signed. null where the registry publishes no DNSSEC status, as .tr, .gg and .nc do not.
  - Contact entities keyed by role (registrant, administrative, technical, billing, abuse). Keys depend on what the registry/registrar provides. See Terminology → Entity roles for what each role means.
  - Fields the server declared withheld, at the same path as in the record. See Redaction.
  - Where the answer came from, and how it was served.
- metaMeta may be absent
  The full object when the domain resolved; only server and source when it failed; absent for invalid_domain.
- errorstringnot_found may be absent
  Machine-readable error code (present when status is "error"). Values include not_found, domain_reserved, not_registrable, not_supported, lookup_failed, upstream_rate_limited, invalid_domain.
- messagestringThis domain was not found. It may not be registered. may be absent
  Human-readable error message (present when status is "error")
- reasonstring may be absent
  The registry's own wording, on domain_reserved only.
- registrable_domainstring may be absent
  The registered domain the name sits under, on not_registrable only.
- totalinteger3
  Total number of unique domains processed
- successfulinteger2
  Number of successful lookups
- failedinteger1
  Number of failed lookups

Request

curl -X POST https://rdapapi.io/api/v1/domains/bulk \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
      "domains": [
          "google.com",
          "github.com",
          "invalid..com"
      ],
      "follow": false,
      "whois": true
  }'

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.bulkDomains(["google.com", "github.com", "invalid..com"]);

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.bulk_domains(["google.com", "github.com", "invalid..com"])

Response

{
    "results": [
        {
            "domain": "google.com",
            "status": "success",
            "data": {
                "domain": "google.com",
                "unicode_name": null,
                "handle": "2138514_DOMAIN_COM-VRSN",
                "status": [
                    "client delete prohibited",
                    "server delete prohibited"
                ],
                "registrar": {
                    "name": "MarkMonitor Inc.",
                    "iana_id": "292",
                    "abuse_email": "[email protected]",
                    "abuse_phone": "+12086851750",
                    "url": "http://www.markmonitor.com"
                },
                "dates": {
                    "registered": "1997-09-15T04:00:00Z",
                    "expires": "2028-09-14T04:00:00Z",
                    "updated": "2019-09-09T15:39:04Z"
                },
                "nameservers": [
                    "ns1.google.com",
                    "ns2.google.com"
                ],
                "dnssec": false,
                "entities": {}
            },
            "meta": {
                "server": "rdap.verisign.com",
                "source": "rdap",
                "rdap_server": "https://rdap.verisign.com/com/v1/",
                "raw_rdap_url": "https://rdap.verisign.com/com/v1/domain/google.com",
                "cached": true,
                "cache_expires": "2026-02-18T15:30:00Z"
            }
        },
        {
            "domain": "github.com",
            "status": "success",
            "data": {
                "domain": "github.com",
                "unicode_name": null,
                "handle": "1264983250_DOMAIN_COM-VRSN",
                "status": [
                    "client delete prohibited",
                    "client transfer prohibited"
                ],
                "registrar": {
                    "name": "MarkMonitor Inc.",
                    "iana_id": "292",
                    "abuse_email": "[email protected]",
                    "abuse_phone": "+12086851750",
                    "url": "http://www.markmonitor.com"
                },
                "dates": {
                    "registered": "2007-10-09T18:20:50Z",
                    "expires": "2026-10-09T18:20:50Z",
                    "updated": "2024-09-08T09:09:41Z"
                },
                "nameservers": [
                    "dns1.p08.nsone.net",
                    "dns2.p08.nsone.net"
                ],
                "dnssec": false,
                "entities": {}
            },
            "meta": {
                "server": "rdap.verisign.com",
                "source": "rdap",
                "rdap_server": "https://rdap.verisign.com/com/v1/",
                "raw_rdap_url": "https://rdap.verisign.com/com/v1/domain/github.com",
                "cached": true,
                "cache_expires": "2026-02-18T16:00:00Z"
            }
        },
        {
            "domain": "invalid..com",
            "status": "error",
            "error": "invalid_domain",
            "message": "The provided domain name is not valid."
        }
    ],
    "summary": {
        "total": 3,
        "successful": 2,
        "failed": 1
    }
}

IP

Look up an IP address or CIDR block.

IP Address Lookup

GET/ip/{ip}

The network an IPv4 or IPv6 address belongs to: the most specific allocation, or the exact block for a CIDR.

Parameters

ipstringRequiredpath: IPv4 or IPv6 address, optionally with CIDR prefix (e.g. 8.8.8.8 or 8.8.8.0/24)

Status codes

200

Successful lookup

400

Invalid IP address format

404

No RDAP data found for this IP address.

not_found — the range is covered, but the address has no record.
not_supported — the address is outside every allocated range.

502

The registry failed to answer (lookup_failed), or we did (bad_gateway). See Errors.

503

Upstream RDAP server temporarily rate-limited

Plus the common errors.

Response fields (47)

handlestring | nullNET-8-8-8-0-2
Registry-assigned handle
namestring | nullGOGL
Network name
typestring | nullDIRECT ALLOCATION
Allocation type
start_addressstring | null8.8.8.0
Start of the IP address range
end_addressstring | null8.8.8.255
End of the IP address range
ip_versionstring | nullv4
IP version (v4 or v6)
parent_handlestring | nullNET-8-0-0-0-0
Parent network handle
countrystring | nullUS
Country code (if provided by registry)
statusstring[]["active"]
Status codes
- registeredstring | null1997-09-15T04:00:00Z
- expiresstring | null2028-09-14T04:00:00Z
- updatedstring | null2019-09-09T15:39:04Z
Contact entities keyed by role (registrant, administrative, technical, billing, abuse)
- One contact. Any field may be null or withheld.
  - handlestring | nullORG-ARAD1-AP
    Registry handle for this entity
  - namestring | null
  - organizationstring | nullGoogle LLC
  - emailstring | null
  - phonestring | null
    Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
  - addressstring | null
  - contact_urlstring | nullhttps://domaincontact.registrar.cloudflare.com/example.com
    Where a server withholds email and publishes a web form instead, this carries it.
  - country_codestring | nullUS
    ISO 3166-1 alpha-2 country code from the address. Unlike the text fields, a redaction placeholder here is dropped to null rather than passed through — it is not a country code.
- administrativeContact may be absent
  One contact. Any field may be null or withheld.
- technicalContact may be absent
  One contact. Any field may be null or withheld.
- abuseContact may be absent
  One contact. Any field may be null or withheld.
- billingContact may be absent
  One contact. Any field may be null or withheld.
cidrstring[]["8.8.8.0/24"]
CIDR notation for the network
geofeedstring | nullhttps://geofeed.ipxo.com/geofeed.txt
The network's RFC 8805 geofeed URL, as published. null when there is none.
Remarks from the registry (network description, abuse info, etc.)
- titlestring | nulldescription
- descriptionstringAPNIC and Cloudflare DNS Resolver project Routed globally by AS13335/Cloudflare
port43string | nullwhois.apnic.net
Legacy WHOIS server hostname
Fields the server declared withheld, at the same path as in the record. See Redaction.
- handlestringremoval may be absent
  removal, emptyValue, partialValue or replacementValue; see Redaction.
- registrarobject may be absent
  Claims about the top-level registrar object. Domain lookups only.
- entitiesobject may be absent
  Claims keyed by contact role, then by field within that contact.
Where the answer came from, and how it was served.
- serverstring | nullrdap.verisign.com
  Host that answered, as /tlds reports it (usable as ?server=). May be null on old cached records.
- sourcestringrdap
  Which protocol answered. Always rdap except on domain lookups, where a TLD with no RDAP server is answered over WHOIS.
- rdap_serverstringhttps://rdap.verisign.com/com/v1/ may be absent
  Base URL of the RDAP server, present only when source is rdap. Use server for the host that answered, or raw_rdap_url for the exact endpoint queried.
- raw_rdap_urlstringhttps://rdap.verisign.com/com/v1/domain/google.com may be absent
  Direct URL to the raw RDAP response. Absent when source is whois, which has no URL form, or when a stored snapshot answered.
- cachedbooleantrue may be absent
  Whether the response was served from cache. Omitted from the partial meta of a failed bulk entry.
- cache_expiresstring2026-02-18T15:30:00Z may be absent
  Cache expiration time (ISO 8601). Omitted from the partial meta of a failed bulk entry.
- followedboolean may be absent
  Whether the registrar's RDAP server was queried for richer data. Only present when ?follow=true is used and source is rdap.
- registrar_rdap_serverstring | null may be absent
  URL of the registrar's RDAP record the registry linked to. Only present when ?follow=true is used.
- follow_errorstring | null may be absent
  Error message if the follow request failed. Only present when ?follow=true is used and the request fails.

Request

curl https://rdapapi.io/api/v1/ip/8.8.8.8 \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.ip("8.8.8.8");

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.ip("8.8.8.8")

Response

{
    "handle": "NET-8-8-8-0-2",
    "name": "GOGL",
    "type": "DIRECT ALLOCATION",
    "start_address": "8.8.8.0",
    "end_address": "8.8.8.255",
    "ip_version": "v4",
    "parent_handle": "NET-8-0-0-0-0",
    "country": null,
    "status": [
        "active"
    ],
    "dates": {
        "registered": "2023-12-28T22:24:33Z",
        "expires": null,
        "updated": "2023-12-28T22:24:56Z"
    },
    "entities": {
        "registrant": {
            "handle": "GOGL",
            "name": "Google LLC",
            "organization": null,
            "email": null,
            "phone": null,
            "address": "1600 Amphitheatre Parkway\nMountain View\nCA\n94043\nUnited States",
            "contact_url": null,
            "country_code": null
        }
    },
    "cidr": [
        "8.8.8.0/24"
    ],
    "geofeed": null,
    "remarks": [],
    "port43": "whois.arin.net",
    "meta": {
        "server": "rdap.arin.net",
        "source": "rdap",
        "rdap_server": "https://rdap.arin.net/registry/",
        "raw_rdap_url": "https://rdap.arin.net/registry/ip/8.8.8.8",
        "cached": false,
        "cache_expires": "2026-02-24T15:30:00Z"
    }
}

ASN

Look up an Autonomous System Number.

ASN Lookup

GET/asn/{asn}

Query RDAP registration data for an ASN.

Parameters

asnstringRequiredpath: Autonomous System Number (1–4,294,967,295), optionally prefixed with "AS"

Status codes

200

Successful lookup

400

Invalid ASN format

404

No RDAP data found for this ASN.

not_found — the range is covered, but the number has no record.
not_supported — the number is outside every allocated range.

502

The registry failed to answer (lookup_failed), or we did (bad_gateway). See Errors.

503

Upstream RDAP server temporarily rate-limited

Plus the common errors.

Response fields (43)

handlestring | nullAS15169
Registry-assigned handle
namestring | nullGOOGLE
Autonomous system name
typestring | null
Allocation type
start_autnuminteger | null15169
Start of the ASN range
end_autnuminteger | null15169
End of the ASN range
countrystring | null
ISO 3166-1 alpha-2 country code, from the record or else a contact's address. APNIC and Brazil's registro.br usually publish one; ARIN, RIPE NCC, AFRINIC and LACNIC usually don't.
statusstring[]["active"]
Status codes
- registeredstring | null1997-09-15T04:00:00Z
- expiresstring | null2028-09-14T04:00:00Z
- updatedstring | null2019-09-09T15:39:04Z
Contact entities keyed by role (registrant, administrative, technical, billing, abuse)
- One contact. Any field may be null or withheld.
  - handlestring | nullORG-ARAD1-AP
    Registry handle for this entity
  - namestring | null
  - organizationstring | nullGoogle LLC
  - emailstring | null
  - phonestring | null
    Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
  - addressstring | null
  - contact_urlstring | nullhttps://domaincontact.registrar.cloudflare.com/example.com
    Where a server withholds email and publishes a web form instead, this carries it.
  - country_codestring | nullUS
    ISO 3166-1 alpha-2 country code from the address. Unlike the text fields, a redaction placeholder here is dropped to null rather than passed through — it is not a country code.
- administrativeContact may be absent
  One contact. Any field may be null or withheld.
- technicalContact may be absent
  One contact. Any field may be null or withheld.
- abuseContact may be absent
  One contact. Any field may be null or withheld.
- billingContact may be absent
  One contact. Any field may be null or withheld.
Remarks from the registry (AS description, abuse info, etc.)
- titlestring | nulldescription
- descriptionstringAPNIC and Cloudflare DNS Resolver project Routed globally by AS13335/Cloudflare
port43string | nullwhois.arin.net
Legacy WHOIS server hostname
Fields the server declared withheld, at the same path as in the record. See Redaction.
- handlestringremoval may be absent
  removal, emptyValue, partialValue or replacementValue; see Redaction.
- registrarobject may be absent
  Claims about the top-level registrar object. Domain lookups only.
- entitiesobject may be absent
  Claims keyed by contact role, then by field within that contact.
Where the answer came from, and how it was served.
- serverstring | nullrdap.verisign.com
  Host that answered, as /tlds reports it (usable as ?server=). May be null on old cached records.
- sourcestringrdap
  Which protocol answered. Always rdap except on domain lookups, where a TLD with no RDAP server is answered over WHOIS.
- rdap_serverstringhttps://rdap.verisign.com/com/v1/ may be absent
  Base URL of the RDAP server, present only when source is rdap. Use server for the host that answered, or raw_rdap_url for the exact endpoint queried.
- raw_rdap_urlstringhttps://rdap.verisign.com/com/v1/domain/google.com may be absent
  Direct URL to the raw RDAP response. Absent when source is whois, which has no URL form, or when a stored snapshot answered.
- cachedbooleantrue may be absent
  Whether the response was served from cache. Omitted from the partial meta of a failed bulk entry.
- cache_expiresstring2026-02-18T15:30:00Z may be absent
  Cache expiration time (ISO 8601). Omitted from the partial meta of a failed bulk entry.
- followedboolean may be absent
  Whether the registrar's RDAP server was queried for richer data. Only present when ?follow=true is used and source is rdap.
- registrar_rdap_serverstring | null may be absent
  URL of the registrar's RDAP record the registry linked to. Only present when ?follow=true is used.
- follow_errorstring | null may be absent
  Error message if the follow request failed. Only present when ?follow=true is used and the request fails.

Request

curl https://rdapapi.io/api/v1/asn/15169 \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.asn("15169");

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.asn("15169")

Response

{
    "handle": "AS15169",
    "name": "GOOGLE",
    "type": null,
    "start_autnum": 15169,
    "end_autnum": 15169,
    "country": null,
    "status": [
        "active"
    ],
    "dates": {
        "registered": "2000-03-30T05:00:00Z",
        "expires": null,
        "updated": "2012-02-24T14:44:34Z"
    },
    "entities": {
        "registrant": {
            "handle": "GOGL",
            "name": "Google LLC",
            "organization": null,
            "email": null,
            "phone": null,
            "address": "1600 Amphitheatre Parkway\nMountain View\nCA\n94043\nUnited States",
            "contact_url": null,
            "country_code": null
        },
        "technical": {
            "handle": "ZG39-ARIN",
            "name": "Google LLC",
            "organization": "Google LLC",
            "email": "[email protected]",
            "phone": "+16502530000",
            "address": "1600 Amphitheatre Parkway\nMountain View\nCA\n94043\nUnited States",
            "contact_url": null,
            "country_code": null
        }
    },
    "remarks": [],
    "port43": "whois.arin.net",
    "meta": {
        "server": "rdap.arin.net",
        "source": "rdap",
        "rdap_server": "https://rdap.arin.net/registry/",
        "raw_rdap_url": "https://rdap.arin.net/registry/autnum/15169",
        "cached": false,
        "cache_expires": "2026-02-24T15:30:00Z"
    }
}

Nameserver

Look up a nameserver host record, for the registries that publish one.

Nameserver Lookup

GET/nameserver/{host}

Registration data for a nameserver hostname, from the registries that publish one.

Parameters

hoststringRequiredpath: Nameserver hostname to look up

Status codes

200

Successful lookup

400

Invalid nameserver hostname format

404

No RDAP data found for this nameserver.

not_found — the TLD is covered, but no record exists for this host.
not_supported — the nameserver's TLD has no RDAP coverage.

502

The registry failed to answer (lookup_failed), or we did (bad_gateway). See Errors.

503

Upstream RDAP server temporarily rate-limited

Plus the common errors.

Response fields (39)

ldh_namestringns1.google.com
Nameserver hostname (lowercase). Empty string if the upstream returned a value that is not a valid LDH hostname.
unicode_namestring | null
Unicode form as the registry sends it; some send the ASCII name
handlestring | nullNS1.GOOGLE.COM
Registry-assigned handle
- v4string[]["216.239.32.10"]
  IPv4 addresses
- v6string[]["2001:4860:4802:32::a"]
  IPv6 addresses
statusstring[]["active"]
Status codes
- registeredstring | null1997-09-15T04:00:00Z
- expiresstring | null2028-09-14T04:00:00Z
- updatedstring | null2019-09-09T15:39:04Z
Contact entities keyed by role (registrant, administrative, technical, billing, abuse)
- One contact. Any field may be null or withheld.
  - handlestring | nullORG-ARAD1-AP
    Registry handle for this entity
  - namestring | null
  - organizationstring | nullGoogle LLC
  - emailstring | null
  - phonestring | null
    Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
  - addressstring | null
  - contact_urlstring | nullhttps://domaincontact.registrar.cloudflare.com/example.com
    Where a server withholds email and publishes a web form instead, this carries it.
  - country_codestring | nullUS
    ISO 3166-1 alpha-2 country code from the address. Unlike the text fields, a redaction placeholder here is dropped to null rather than passed through — it is not a country code.
- administrativeContact may be absent
  One contact. Any field may be null or withheld.
- technicalContact may be absent
  One contact. Any field may be null or withheld.
- billingContact may be absent
  One contact. Any field may be null or withheld.
- abuseContact may be absent
  One contact. Any field may be null or withheld.
Fields the server declared withheld, at the same path as in the record. See Redaction.
- handlestringremoval may be absent
  removal, emptyValue, partialValue or replacementValue; see Redaction.
- registrarobject may be absent
  Claims about the top-level registrar object. Domain lookups only.
- entitiesobject may be absent
  Claims keyed by contact role, then by field within that contact.
Where the answer came from, and how it was served.
- serverstring | nullrdap.verisign.com
  Host that answered, as /tlds reports it (usable as ?server=). May be null on old cached records.
- sourcestringrdap
  Which protocol answered. Always rdap except on domain lookups, where a TLD with no RDAP server is answered over WHOIS.
- rdap_serverstringhttps://rdap.verisign.com/com/v1/ may be absent
  Base URL of the RDAP server, present only when source is rdap. Use server for the host that answered, or raw_rdap_url for the exact endpoint queried.
- raw_rdap_urlstringhttps://rdap.verisign.com/com/v1/domain/google.com may be absent
  Direct URL to the raw RDAP response. Absent when source is whois, which has no URL form, or when a stored snapshot answered.
- cachedbooleantrue may be absent
  Whether the response was served from cache. Omitted from the partial meta of a failed bulk entry.
- cache_expiresstring2026-02-18T15:30:00Z may be absent
  Cache expiration time (ISO 8601). Omitted from the partial meta of a failed bulk entry.
- followedboolean may be absent
  Whether the registrar's RDAP server was queried for richer data. Only present when ?follow=true is used and source is rdap.
- registrar_rdap_serverstring | null may be absent
  URL of the registrar's RDAP record the registry linked to. Only present when ?follow=true is used.
- follow_errorstring | null may be absent
  Error message if the follow request failed. Only present when ?follow=true is used and the request fails.

Request

curl https://rdapapi.io/api/v1/nameserver/ns1.google.com \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.nameserver("ns1.google.com");

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.nameserver("ns1.google.com")

Response

{
    "ldh_name": "ns1.google.com",
    "unicode_name": null,
    "handle": "NS1.GOOGLE.COM",
    "ip_addresses": {
        "v4": [
            "216.239.32.10"
        ],
        "v6": [
            "2001:4860:4802:32::a"
        ]
    },
    "status": [
        "active"
    ],
    "dates": {
        "registered": "2004-01-01T00:00:00Z",
        "expires": null,
        "updated": "2024-06-15T12:00:00Z"
    },
    "entities": {},
    "meta": {
        "server": "rdap.verisign.com",
        "source": "rdap",
        "rdap_server": "https://rdap.verisign.com/com/v1/",
        "raw_rdap_url": "https://rdap.verisign.com/com/v1/nameserver/ns1.google.com",
        "cached": false,
        "cache_expires": "2026-02-24T15:30:00Z"
    }
}

Entity

Look up a contact or organization by RDAP handle.

Entity Lookup

GET/entity/{handle}

An organization or contact at ARIN, RIPE NCC, APNIC, LACNIC or AFRINIC, by handle. The suffix picks the registry (-RIPE, -AP…); a bare handle like GOGL goes to ARIN.

Parameters

handlestringRequiredpath: Entity handle (e.g. GOGL, ABUSE5250-ARIN, ORG-GLLC1-RIPE)

Status codes

200

Successful lookup

400

Invalid entity handle format

404

No RDAP data found for this entity handle.

not_found — the handle belongs to a regional registry, but no matching entity exists.
not_supported — the handle does not look like one from a supported registry.

502

The registry failed to answer (lookup_failed), or we did (bad_gateway). See Errors.

503

Upstream RDAP server temporarily rate-limited

Plus the common errors.

Response fields (61)

handlestring | nullGOGL
Registry-assigned entity handle
namestring | nullGoogle LLC
Full name (fn from vCard)
organizationstring | nullGoogle LLC
Organization name
emailstring | null
Contact email address
phonestring | null
Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
addressstring | null
Postal address
contact_urlstring | null
Web form or page for reaching this contact, where one is published instead of an email address.
country_codestring | nullUS
ISO 3166-1 alpha-2 country code
rolesstring[]["registrant"]
Roles this entity serves
statusstring[]["active"]
Status codes
- registeredstring | null1997-09-15T04:00:00Z
- expiresstring | null2028-09-14T04:00:00Z
- updatedstring | null2019-09-09T15:39:04Z
- titlestring | nulldescription
- descriptionstringAPNIC and Cloudflare DNS Resolver project Routed globally by AS13335/Cloudflare
port43string | nullwhois.arin.net
Legacy WHOIS server hostname
Public identifiers (e.g. ARIN OrgID, IANA Registrar ID)
- typestring | nullARIN OrgID
  Type of public identifier
- identifierstring | nullGOGL
  The identifier value
Nested contact entities keyed by role
- One contact. Any field may be null or withheld.
  - handlestring | nullORG-ARAD1-AP
    Registry handle for this entity
  - namestring | null
  - organizationstring | nullGoogle LLC
  - emailstring | null
  - phonestring | null
    Voice telephone number in E.164, with a ;ext=42 suffix when the registry supplies an extension.
  - addressstring | null
  - contact_urlstring | nullhttps://domaincontact.registrar.cloudflare.com/example.com
    Where a server withholds email and publishes a web form instead, this carries it.
  - country_codestring | nullUS
    ISO 3166-1 alpha-2 country code from the address. Unlike the text fields, a redaction placeholder here is dropped to null rather than passed through — it is not a country code.
- abuseContact may be absent
  One contact. Any field may be null or withheld.
- administrativeContact may be absent
  One contact. Any field may be null or withheld.
- technicalContact may be absent
  One contact. Any field may be null or withheld.
- billingContact may be absent
  One contact. Any field may be null or withheld.
Autonomous system numbers owned by this entity
- handlestring | nullAS15169
- namestring | nullGOOGLE
- start_autnuminteger | null15169
- end_autnuminteger | null15169
IP network blocks owned by this entity
- handlestring | nullNET-8-8-8-0-2
- namestring | nullGOGL
- start_addressstring | null8.8.8.0
- end_addressstring | null8.8.8.255
- ip_versionstring | nullv4
- cidrstring[]["8.8.8.0/24"]
Fields the server declared withheld, at the same path as in the record. See Redaction.
- handlestringremoval may be absent
  removal, emptyValue, partialValue or replacementValue; see Redaction.
- registrarobject may be absent
  Claims about the top-level registrar object. Domain lookups only.
- entitiesobject may be absent
  Claims keyed by contact role, then by field within that contact.
Where the answer came from, and how it was served.
- serverstring | nullrdap.verisign.com
  Host that answered, as /tlds reports it (usable as ?server=). May be null on old cached records.
- sourcestringrdap
  Which protocol answered. Always rdap except on domain lookups, where a TLD with no RDAP server is answered over WHOIS.
- rdap_serverstringhttps://rdap.verisign.com/com/v1/ may be absent
  Base URL of the RDAP server, present only when source is rdap. Use server for the host that answered, or raw_rdap_url for the exact endpoint queried.
- raw_rdap_urlstringhttps://rdap.verisign.com/com/v1/domain/google.com may be absent
  Direct URL to the raw RDAP response. Absent when source is whois, which has no URL form, or when a stored snapshot answered.
- cachedbooleantrue may be absent
  Whether the response was served from cache. Omitted from the partial meta of a failed bulk entry.
- cache_expiresstring2026-02-18T15:30:00Z may be absent
  Cache expiration time (ISO 8601). Omitted from the partial meta of a failed bulk entry.
- followedboolean may be absent
  Whether the registrar's RDAP server was queried for richer data. Only present when ?follow=true is used and source is rdap.
- registrar_rdap_serverstring | null may be absent
  URL of the registrar's RDAP record the registry linked to. Only present when ?follow=true is used.
- follow_errorstring | null may be absent
  Error message if the follow request failed. Only present when ?follow=true is used and the request fails.

Request

curl https://rdapapi.io/api/v1/entity/GOGL \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.entity("GOGL");

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.entity("GOGL")

Response

{
    "handle": "GOGL",
    "name": "Google LLC",
    "organization": "Google LLC",
    "email": null,
    "phone": null,
    "address": "1600 Amphitheatre Parkway\nMountain View\nCA\n94043\nUS",
    "contact_url": null,
    "country_code": "US",
    "roles": [
        "registrant"
    ],
    "status": [
        "active"
    ],
    "dates": {
        "registered": "2000-03-30T05:00:00Z",
        "expires": null,
        "updated": "2019-10-31T19:45:45Z"
    },
    "remarks": [
        {
            "title": "Registration Comments",
            "description": "Please note that the recommended way to file abuse complaints are located in the following links."
        }
    ],
    "port43": "whois.arin.net",
    "public_ids": [
        {
            "type": "ARIN OrgID",
            "identifier": "GOGL"
        }
    ],
    "entities": {
        "abuse": {
            "handle": "ABUSE5250-ARIN",
            "name": "Abuse",
            "organization": null,
            "email": "[email protected]",
            "phone": "+16502530000",
            "address": null,
            "contact_url": null,
            "country_code": null
        }
    },
    "autnums": [
        {
            "handle": "AS15169",
            "name": "GOOGLE",
            "start_autnum": 15169,
            "end_autnum": 15169
        },
        {
            "handle": "AS36040",
            "name": "YOUTUBE",
            "start_autnum": 36040,
            "end_autnum": 36040
        }
    ],
    "networks": [
        {
            "handle": "NET-8-8-8-0-2",
            "name": "GOGL",
            "start_address": "8.8.8.0",
            "end_address": "8.8.8.255",
            "ip_version": "v4",
            "cidr": [
                "8.8.8.0/24"
            ]
        }
    ],
    "meta": {
        "server": "rdap.arin.net",
        "source": "rdap",
        "rdap_server": "https://rdap.arin.net/registry/",
        "raw_rdap_url": "https://rdap.arin.net/registry/entity/GOGL",
        "cached": false,
        "cache_expires": "2026-02-24T15:30:00Z"
    }
}

TLDs

Check which TLDs are supported, in bulk or one at a time.

List Supported TLDs

GET/tlds

Every TLD we answer for: its protocol, when support was added, and how often its registry fills the main fields (field availability). Free, sorted by tld, and sent with an ETag: pass it as If-None-Match to get 304 Not Modified.

Parameters

sincestringquery: ISO 8601 timestamp. Only TLDs supported after it.
serverstringquery: Only TLDs answered by this server, e.g. rdap.verisign.com.

Status codes

200: List of supported TLDs
304: Not modified. Returned when the If-None-Match header matches the current ETag. No response body.
400: Invalid since query parameter

Plus the common errors.

Response fields (21)

- tldstringcom
  Lowercase TLD label without a leading dot.
- protocolstringrdap
  Which protocol answers for this TLD. whois marks the TLDs IANA lists no RDAP server for.
- supported_sincestring
  When this TLD was first added to the RDAP API index. Not the same as when IANA delegated the TLD.
- serverstringrdap.verisign.com
  Hostname of the upstream that answers for this TLD. This is what ?server= filters on, and what a lookup's meta.server returns.
- rdap_server_hoststring | nullrdap.verisign.com
  Superseded by server. Null when protocol is whois.
- rdap_server_urlstring | nullhttps://rdap.verisign.com/com/v1/
  Full URL of the upstream RDAP server. Null when protocol is whois, which has no URL form.
- How often the registry fills each field, without follow. null for WHOIS TLDs and until there is enough data.
  - registrarstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - registered_atstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - expires_atstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - nameserversstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - statusstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
- computed_atstring
  Server time when the cached payload was built. May be up to 1 hour old.
- countinteger
  Number of TLDs in data (after any filtering).
- coveragenumber0.93
  Share of RDAP TLDs with enough data for field_availability.
- Percentage cutoffs used to pick each label:
  
  always = populated in 99% or more of responses
  
  usually = 80% or more
  
  sometimes = more than 0%
  
  never = 0%
  - alwaysnumber0.99
  - usuallynumber0.8
  - sometimesnumber0

Request

curl https://rdapapi.io/api/v1/tlds \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.tlds();

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.tlds()

Response

{
    "data": [
        {
            "tld": "com",
            "supported_since": "2026-03-07T00:00:00Z",
            "rdap_server_host": "rdap.verisign.com",
            "rdap_server_url": "https://rdap.verisign.com/com/v1/",
            "field_availability": {
                "registrar": "sometimes",
                "registered_at": "always",
                "expires_at": "always",
                "nameservers": "always",
                "status": "always"
            }
        },
        {
            "tld": "fr",
            "supported_since": "2026-03-07T00:00:00Z",
            "rdap_server_host": "rdap.nic.fr",
            "rdap_server_url": "https://rdap.nic.fr/",
            "field_availability": null
        }
    ],
    "meta": {
        "computed_at": "2026-04-22T10:00:00Z",
        "count": 2,
        "coverage": 0.5,
        "thresholds": {
            "always": 0.99,
            "usually": 0.8,
            "sometimes": 0
        }
    }
}

Get a Single TLD

GET/tlds/{tld}

The same object as in the list, for one TLD. Free.

Parameters

tldstringRequiredpath: Lowercase TLD label without a leading dot (e.g. com, fr, co.uk).

Status codes

200: TLD found
304: Not modified.
404: Unknown TLD

Plus the common errors.

Response fields (19)

- tldstringcom
  Lowercase TLD label without a leading dot.
- protocolstringrdap
  Which protocol answers for this TLD. whois marks the TLDs IANA lists no RDAP server for.
- supported_sincestring
  When this TLD was first added to the RDAP API index. Not the same as when IANA delegated the TLD.
- serverstringrdap.verisign.com
  Hostname of the upstream that answers for this TLD. This is what ?server= filters on, and what a lookup's meta.server returns.
- rdap_server_hoststring | nullrdap.verisign.com
  Superseded by server. Null when protocol is whois.
- rdap_server_urlstring | nullhttps://rdap.verisign.com/com/v1/
  Full URL of the upstream RDAP server. Null when protocol is whois, which has no URL form.
- How often the registry fills each field, without follow. null for WHOIS TLDs and until there is enough data.
  - registrarstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - registered_atstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - expires_atstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - nameserversstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
  - statusstring
    Qualitative bucket describing how often a field is populated in the TLD's registry RDAP response.
- computed_atstring
- Percentage cutoffs used to pick each label:
  
  always = populated in 99% or more of responses
  
  usually = 80% or more
  
  sometimes = more than 0%
  
  never = 0%
  - alwaysnumber0.99
  - usuallynumber0.8
  - sometimesnumber0

Request

curl https://rdapapi.io/api/v1/tlds/com \
  -H "Authorization: Bearer YOUR_API_KEY"

import { RdapClient } from "rdapapi";

const client = new RdapClient("YOUR_API_KEY");
const result = await client.tld("com");

from rdapapi import RdapApi

api = RdapApi("YOUR_API_KEY")
result = api.tld("com")

Response

{
    "data": {
        "tld": "com",
        "supported_since": "2026-03-07T00:00:00Z",
        "rdap_server_host": "rdap.verisign.com",
        "rdap_server_url": "https://rdap.verisign.com/com/v1/",
        "field_availability": {
            "registrar": "sometimes",
            "registered_at": "always",
            "expires_at": "always",
            "nameservers": "always",
            "status": "always"
        }
    },
    "meta": {
        "computed_at": "2026-04-22T10:00:00Z",
        "thresholds": {
            "always": 0.99,
            "usually": 0.8,
            "sometimes": 0
        }
    }
}

Health

Uptime checks.

Health Check

GET/ping

Returns {"status":"ok"} when the API is up. No key, free.

Status codes

200: API is reachable

Plus the common errors.

Response fields (1)

statusstringok

Errors

Errors are JSON with an error code to branch on and a message to show. Some add retry_after, in seconds.

Status	`error`	Meaning	Retry?
400	`invalid_domain`, `invalid_ip`, `invalid_asn`, `invalid_nameserver`, `invalid_handle`, `invalid_prefix`, `invalid_since`	The identifier is malformed.	No
4xx	`bad_request`, `method_not_allowed`, `payload_too_large`	Malformed request, wrong method or body too large.	No
401	`unauthenticated`	Missing or invalid API key.	No
403	`subscription_required`	No active subscription.	No
403	`plan_upgrade_required`	Bulk needs Pro or Business.	No
403	`forbidden`	Your IP is temporarily blocked.	Later
404	`not_found`	No record. For a domain, the name may be free.	No
404	`domain_reserved`	Reserved by the registry; `reason` says why.	No
404	`not_registrable`	Below a registration, like `www.example.com`; look up `registrable_domain`.	No
404	`not_supported`	We can't query this TLD, zone or range.	No
404	`unknown_endpoint`	No such endpoint.	No
422	`request_failed`	Invalid body; `errors` lists the fields.	No
429	`rate_limit_exceeded`	Per-minute limit reached.	After `retry_after`
429	`quota_exceeded`	Monthly quota spent.	Next month
429	`too_many_requests`	Too many requests at once.	Shortly
502	`lookup_failed`	The registry failed to answer.	Yes
503	`temporarily_unavailable`	The registry is throttling us.	After `retry_after`
5xx	`bad_gateway`, `service_unavailable`, `gateway_timeout`, `server_error`	A problem on our side.	Shortly

Lookup 404s are billed like successes (Limits and caching). Send Accept: application/json so an error from our CDN stays JSON; treat any non-JSON error as a retryable network failure.

Limits and caching

Rate limit. X-RateLimit-Limit and X-RateLimit-Remaining track your per-minute limit. Over it you get 429 rate_limit_exceeded with Retry-After. A bulk request spends one unit per domain; very large bursts are also cut at the edge (429 too_many_requests).

Quota. Successful lookups and lookup 404s count, cached or not; nothing else does, and /tlds and /ping are free. ?follow=true counts once; a bulk request counts each domain. Over quota you get 429 quota_exceeded until the 1st of next month (UTC).

Caching. Lookups are cached for up to 24 hours (meta.cached, meta.cache_expires), may be served up to 24 hours past expiry while refreshing, and up to 7 days old if the registry doesn't answer. /tlds supports ETag revalidation.

WHOIS fallback

TLDs with no RDAP server, mostly ccTLDs such as .it, .eu and .tr, are read from the registry's WHOIS server and returned in the same shape with meta.source: whois. /tlds lists them as protocol: whois. Errors, snapshots and billing work the same. Send whois=false to refuse it (404 not_supported). Domains only: the five RIRs all run RDAP.

Terminology

Thin and thick registries

A thin registry (.com, .net, .cc, .tv) leaves contacts to the registrar. A thick registry, like most ccTLDs and newer gTLDs, publishes the full record itself.

Follow-through

?follow=true also queries the registrar named in the registry's answer and merges in its contacts. If that fails you still get the registry data, with meta.followed: false and a meta.follow_error; false with no error means there was nothing to follow.

Entity roles

entities is keyed by role: registrant (the holder), administrative, technical, billing and abuse, one contact each. The registrar is the top-level registrar field. Which roles appear depends on what the registry publishes; placeholders such as Redacted for Privacy are passed through as sent.

Field availability

/tlds rates how often a TLD fills each field over 90 days: always (≥99%), usually (≥80%), sometimes or never, and null until there is enough data.

Status values

status uses the lowercase RDAP names (client transfer prohibited); EPP forms like clientTransferProhibited are converted. Registry-specific values pass through, so don't match against a closed list. Every status, explained.

Redaction

Since GDPR most contact fields are null. When a registry says why, redacted mirrors the record (redacted.entities.registrant.name) with the method: removal or emptyValue (blanked), partialValue (incomplete), or replacementValue, a genuine-looking substitute such as a forwarding address. No redacted doesn't mean nothing was withheld.