Validate an Email - Relaybase

Validate a single email address using Relaybase.

Request

POST https://api.tryrelaybase.com/v1/email/single-validate
X-RB-Key: rb_key_<token>
Accept: application/json

{
  "email": "user@example.com",
  "mode": "medium"
}

Body parameters

Field	Type	Required	Description
`email`	string	Yes	The email address to validate
`mode`	string	No	Validation depth: `fast`, `medium`, or `deep`. Lighter modes return faster; deeper modes run more thorough checks, including SMTP verification.

Response

{
  "data": {
    "catch_all": false,
    "is_disposable": false,
    "is_free": true,
    "is_role_based": false,
    "is_valid": true,
    "mx_valid": true,
    "reason": "Mailbox verified via SMTP",
    "result": "jane@company.com",
    "score": 85,
    "smtp_code": 250,
    "status": "valid",
    "suggestion": "Email appears fully deliverable",
    "syntax_valid": true
  },
  "message": "result",
  "status": 200,
  "success": true
}

See Validation Results for what each field in data means, and how status and score relate to each other.

Prefer not to hit the HTTP API directly? Check out the Go SDK, Node.js SDK, PHP SDK, or Python SDK.

This endpoint is designed for individual validation requests. Don’t loop over a list of emails with sequential calls — see Rate Limits.