Go

Official Go SDK for the Relaybase API

Go client for the Relaybase email validation API.

GitHub Repository

Source, issues, and releases for the Relaybase Go SDK.

Requirements

• Go 1.22+

Installation

go get github.com/Vusion-Labs/relaybase_golang_sdk

Authentication

Get your API key from the Relaybase dashboard and pass it to relaybase.New:

client := relaybase.New("rb_key_...")

By default the client talks to https://api.relaybase.com. To point at a different environment:

client := relaybase.New("rb_key_...", relaybase.WithBaseURL("https://staging.api.relaybase.com"))

Quick start

package main

import (
	"fmt"
	"log"

	"github.com/Vusion-Labs/relaybase_golang_sdk"
)

func main() {
	client := relaybase.New("rb_key_...")

	result, err := client.SingleVerify("[e-mail]", relaybase.EmailModeCheckFast)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.IsValid) // true
	fmt.Println(result.Status)  // "valid"
}

Verifying an email

result, err := client.SingleVerify(email, relaybase.EmailModeCheckFast)

Or with a context (for timeouts/cancellation):

result, err := client.SingleVerifyContext(ctx, email, relaybase.EmailModeCheckFast)

If mode is left as the zero value (""), it defaults to EmailModeCheckFast.

Verification modes

Constant	Value	Description
relaybase.EmailModeCheckFast	"fast"	Fast syntax/MX-level check
relaybase.EmailModeCheckMedium	"medium"	Adds deeper domain/mailbox checks
relaybase.EmailModeCheckDeep	"deep"	Most thorough check, including full SMTP verification

See Validation Results for how these map to the API’s mode field.

Response fields

SingleVerify returns a *relaybase.VerifyResult:

Field	Type	Description
IsValid	bool	Overall validity of the email
Status	string	e.g. "valid", "invalid", "risky"
Score	int	Deliverability score (0–100)
Reason	string	Human-readable explanation of the result
Suggestion	string	Suggested correction or note
SyntaxValid	bool	Whether the address is syntactically valid
MXValid	bool	Whether the domain has valid MX records
SMTPCode	int	SMTP response code from mailbox verification
CatchAll	bool	Whether the domain accepts all addresses (catch-all)
IsDisposable	bool	Whether the address is from a disposable email provider
IsFree	bool	Whether the address is from a free email provider (Gmail, Yahoo, etc.)
IsRoleBased	bool	Whether the address is role-based (e.g. support@, admin@)

Example:

result, err := client.SingleVerify("[e-mail]", relaybase.EmailModeCheckFast)
if err != nil {
	log.Fatal(err)
}

if result.IsValid {
	fmt.Printf("%s is deliverable (score: %d)\n", "[e-mail]", result.Score)
} else {
	fmt.Printf("Invalid: %s\n", result.Reason)
}

Error handling

Errors from the API are returned as error. To inspect the underlying HTTP status:

result, err := client.SingleVerify(email, relaybase.EmailModeCheckFast)
if err != nil {
	if apiErr, ok := relaybase.IsAPIError(err); ok {
		fmt.Println(apiErr.StatusCode) // e.g. 401
		fmt.Println(apiErr.Message)    // e.g. "invalid api key"
	}
	log.Fatal(err)
}

Common status codes:

Code	Meaning
400	Malformed request (e.g. invalid email format)
401	Invalid or missing API key
403	Key valid but not authorized for this action
429	Rate limit / quota exceeded
500	Internal server error

Roadmap

Bulk validation support for validating multiple emails in a single call is in progress and will be added in a future release.