Managing Tags

Tags are unique identifiers you can add to your emails. They help associate emails with your application. They are passed in key/value pairs. After the email is sent, the tag is included in the webhook event. Tags can include ASCII letters, numbers, underscores, or dashes. You can add up to 75 tags per email.

Some examples of when to use a tag:

Associate the email a "customer ID" from your application
Add a label from your database like "free" or "enterprise"
Note the category of email sent, like "welcome" or "password reset"

Here's how you can add custom tags to your emails.

Add tags on the `POST /emails` endpoint

Node.js

import { Resend } from 'resend';const resend = new Resend('re_xxxxxxxxx');await resend.emails.send({  from: 'Acme <onboarding@resend.dev>',  to: ['delivered@resend.dev'],  subject: 'hello world',  html: '<p>it works!</p>',  tags: [    {      name: 'category',      value: 'confirm_email',    },  ],});

PHP

$resend = Resend::client('re_xxxxxxxxx');$resend->emails->send([  'from' => 'Acme <onboarding@resend.dev>',  'to' => ['delivered@resend.dev'],  'subject' => 'hello world',  'html' => '<p>it works!</p>',  'tags' => [    [      'name' => 'category',      'value' => 'confirm_email',    ],  ]]);

Python

import resendresend.api_key = "re_xxxxxxxxx"params: resend.Emails.SendParams = {  "from": "Acme <onboarding@resend.dev>",  "to": ["delivered@resend.dev"],  "subject": "hello world",  "html": "<p>it works!</p>",  "tags": [    {"name": "category", "value": "confirm_email"},  ],}email = resend.Emails.send(params)print(email)

Ruby

require "resend"Resend.api_key = "re_xxxxxxxxx"params = {  "from": "Acme <onboarding@resend.dev>",  "to": ["delivered@resend.dev"],  "subject": "hello world",  "html": "<p>it works!</p>",  "tags": [    {"name": "category", "value": "confirm_email"}  ]}sent = Resend::Emails.send(params)puts sent

package mainimport (	"context"	"fmt"	"github.com/resend/resend-go/v4")func main() {  ctx := context.TODO()  client := resend.NewClient("re_xxxxxxxxx")  params := &resend.SendEmailRequest{      From:        "Acme <onboarding@resend.dev>",      To:          []string{"delivered@resend.dev"},      Text:        "<p>it works!</p>",      Subject:     "hello world",      Tags:        []resend.Tag{{Name: "category", Value: "confirm_email"}},  }  sent, err := client.Emails.SendWithContext(ctx, params)  if err != nil {    panic(err)  }  fmt.Println(sent.Id)}

Rust

use resend_rs::types::{CreateEmailBaseOptions, Tag};use resend_rs::{Resend, Result};#[tokio::main]async fn main() -> Result<()> {  let resend = Resend::new("re_xxxxxxxxx");  let from = "Acme <onboarding@resend.dev>";  let to = ["delivered@resend.dev"];  let subject = "hello world";  let email = CreateEmailBaseOptions::new(from, to, subject)    .with_html("<p>it works!</p>")    .with_tag(Tag::new("category", "confirm_email"));  let _email = resend.emails.send(email).await?;  Ok(())}

Java

import com.resend.*;import com.resend.core.exception.ResendException;import com.resend.services.emails.model.CreateEmailOptions;import com.resend.services.emails.model.CreateEmailResponse;import com.resend.services.emails.model.Tag;public class Main {    public static void main(String[] args) throws ResendException {        Resend resend = new Resend("re_xxxxxxxxx");        Tag tag = Tag.builder()                .name("category")                .value("confirm_email")                .build();        CreateEmailOptions params = CreateEmailOptions.builder()                .from("Acme <onboarding@resend.dev>")                .to("delivered@resend.dev")                .subject("hello world")                .html("<p>it works!</p>")                .tags(tag)                .build();        CreateEmailResponse data = resend.emails().send(params);    }}

.NET

using Resend;IResend resend = ResendClient.Create( "re_xxxxxxxxx" ); // Or from DIvar resp = await resend.EmailSendAsync( new EmailMessage(){    From = "Acme <onboarding@resend.dev>",    To = "delivered@resend.dev",    Subject = "hello world",    HtmlBody = "<p>it works!</p>",    ReplyTo = "onboarding@resend.dev",    Tags = new List<EmailTag> { new EmailTag { Name = "category", Value = "confirm_email" } }} );Console.WriteLine( "Email Id={0}", resp.Content );

cURL

curl -X POST 'https://api.resend.com/emails' \     -H 'Authorization: Bearer re_xxxxxxxxx' \     -H 'Content-Type: application/json' \     -d $'{  "from": "Acme <onboarding@resend.dev>",  "to": ["delivered@resend.dev"],  "subject": "hello world",  "html": "<p>it works!</p>",  "tags": [    {      "name": "category",      "value": "confirm_email"    }  ]}'

CLI

resend emails send \  --from "Acme <onboarding@resend.dev>" \  --to delivered@resend.dev \  --subject "hello world" \  --html "<p>it works!</p>" \  --tags "category=confirm_email"

Add tags on the `POST /emails/batch` endpoint