WHOIS API

API reference

WHOIS HTTP endpoints on api.syndaq.com.

All WHOIS endpoints are served from https://api.syndaq.com/v1/whois/.

Authenticated requests require a valid WHOIS key. Lookup routes require your wh_sec_ secret key.

Endpoints overview

Method	Path	Auth	Purpose
GET	`/v1/whois/lookup`	Secret key	Lookup by `?domain=` query parameter
GET	`/v1/whois/lookup/{domain}`	Secret key	Lookup by domain in the URL path
GET	`/v1/whois/status`	Public or secret key	Plan limits and quota snapshot

Response headers

Successful and error responses may include:

Header	Description
`X-Request-Id`	Unique ID for support and log correlation
`X-RateLimit-Limit`	Plan requests per minute for this key
`X-RateLimit-Remaining`	Requests left in the current minute window
`X-RateLimit-Reset`	Unix timestamp when the minute window resets
`X-Quota-Limit`	Monthly quota for the subscription
`X-Quota-Remaining`	Lookups left this calendar month (UTC)
`X-Quota-Period`	Current quota month (`YYYY-MM`)
`Retry-After`	Seconds to wait after HTTP 429

GET /v1/whois/lookup

Returns registration metadata for a single domain.

Request

Pass the target domain using one of these forms:

GET /v1/whois/lookup/example.com
GET /v1/whois/lookup?domain=example.com

Headers:

Authorization: Bearer wh_sec_YOUR_SECRET_KEY

Success response (200)

{
  "success": true,
  "domain": "example.com",
  "cached": true,
  "fetched_at": "2026-07-15 12:00:00.000",
  "registrar": "RESERVED-Internet Assigned Numbers Authority",
  "created_at": "1995-08-14T04:00:00Z",
  "updated_at": "2024-08-14T07:01:39Z",
  "expires_at": null,
  "domain_age_days": 11280,
  "status": [
    "client delete prohibited",
    "client transfer prohibited",
    "client update prohibited"
  ],
  "nameservers": [
    "a.iana-servers.net",
    "b.iana-servers.net"
  ],
  "request_id": "e6d04020be9b57b1e1069d6e483c0443"
}

Response fields

Field	Type	Description
`domain`	string	Normalized domain that was looked up
`cached`	boolean	`true` when Syndaq already holds a recent result for this lookup
`fetched_at`	string	When this result was last retrieved
`registrar`	string \	null	Registrar display name when available
`created_at`	string \	null	Registration / creation timestamp when available
`updated_at`	string \	null	Last changed timestamp when available
`expires_at`	string \	null	Expiration timestamp when available
`domain_age_days`	integer \	null	Whole days since `created_at`, if known
`status`	array	Status strings for the domain
`nameservers`	array	Nameserver hostnames

Date fields are ISO-8601 strings when present. Some TLDs redact or omit fields; Syndaq returns null rather than inventing values.

GET /v1/whois/status

Returns key status, plan limits, and quota usage without performing a lookup.

Request

GET /v1/whois/status
Authorization: Bearer wh_sec_YOUR_SECRET_KEY

The public key (wh_pub_) is accepted on this route.

Success response (200)

{
  "success": true,
  "status": "active",
  "product": "whois",
  "plan": "starter",
  "rate_limit_per_minute": 120,
  "monthly_quota": 10000,
  "quota_unlimited": false,
  "quota_remaining": 9842,
  "quota_period": "2026-07",
  "database_records": 88000
}

Errors

Failed requests return JSON with success: false, error, error_code, and usually request_id.

HTTP	error_code	Typical cause
400	`invalid_domain`	Missing or malformed domain
401	`missing_credentials`	No API key provided
401	`invalid_api_key`	Unknown, inactive, or revoked key
401	`wrong_key_type`	Public key used on a lookup endpoint
403	`ip_not_allowed`	Caller IP not on the key allowlist
404	`domain_not_found`	Domain could not be resolved
429	`rate_limit_exceeded`	Per-minute limit exceeded
429	`quota_exceeded`	Monthly quota exhausted
502	`lookup_failed`	Temporary lookup failure
500	`internal_error`	Unexpected server error

Handle non-200 responses in your application and retry transient errors with exponential backoff.