Double opt-in

Setting up double opt-in is a process that allows you to verify the email address of a new subscriber.

Creating an unsubscribed contact

When you trigger an event for a contact, they will automatically be subscribed unless you pass subscribed: false along with the event.

When you trigger the event, Plunk's API will return you a JSON object with the contact's ID. You can use this ID to send them a confirmation email with the transactional email API

await fetch('https://api.useplunk.com/v1/track', {
    method: "POST",
    headers: {
        "Content-Type": "application/json",
        "Authorization": "Bearer API_KEY", // Put your API key here
    },
    body: JSON.stringify({
        "event": "new-project",
        "email": "hello@useplunk.com",
        "subscribed": false,
    }),
});

import requests
 
requests.post(
    "https://api.useplunk.com/v1/track",
    headers={
        "Content-Type": "application/json",
        "Authorization": "Bearer API_KEY"  # Put your API key here
    },
    json={
        "event": "new-project",
        "email": "hello@useplunk.com",
        "subscribed": False
    },
)

curl --location --request POST 'https://api.useplunk.com/v1/track' \
--header 'Authorization: Bearer API_KEY' \
--header 'Content-Type: application/json' \
--data-raw '{"email": "hello@useplunk.com", "event": "new-project", "subscribed": false}'

```php
<?php
$client = new Client();

$request = new Request('POST', 'https://api.useplunk.com/v1/track', ['Authorization' => 'Bearer API_KEY', 'Content-Type' => 'application/json'], '{
    "event": "new-project",
    "email": "hello@useplunk.com",
    "subscribed": false
}');

$res = $client->sendAsync($request)->wait();

require "uri"
require "json"
require "net/http"
 
url = URI("https://api.useplunk.com/v1/track")
https = Net::HTTP.new(url.host, url.port)
https.use_ssl = true
request = Net::HTTP::Post.new(url)
 
request["Authorization"] = "Bearer API_KEY" # Put your API key here
request["Content-Type"] = "application/json"
 
request.body = JSON.dump({
    "event": "new-project",
    "email": "hello@useplunk.com",
    "subscribed": false
})
 
response = https.request(request)

Confirming opt-in

With an action

You can leverage Plunk's action to confirm the opt-in. For this you will need to create an transactional template that contains a link to Plunk's hosted subscribe page or a custom-built page that will call the Plunk API to subscribe the contact.

Plunk's hosted pages can be found at the following URLs:

app.useplunk.com/subscribe/contactID
app.useplunk.com/unsubscribe/contactID

When creating a template, you can use the built-in Plunk variables in the editor to automatically fill in the contact's ID.

An image showing how to use Plunk's built-in variables in a link

With a transactional email

Using the contact ID returned from the previous step, you can send a transactional email to the contact. This email will contain a link to the subscription page hosted by Plunk. All contacts have a subscribe and unsubscribe page that can be found at the following URLs:

app.useplunk.com/subscribe/contactID
app.useplunk.com/unsubscribe/contactID

Once the contact confirms their subscription by clicking the button on the page, they will be toggled to a subscribed contact.

await fetch('https://api.useplunk.com/v1/send', {
    method: "POST",
    headers: {
        "Content-Type": "application/json",
        "Authorization": "Bearer SECRET_KEY", // Put your API key here
    },
    body: JSON.stringify({
        "to": "hello@useplunk.com",
        "subject": "Please confirm your email",
        "body": "<h1>Confirm your email</h1><p>Click <a href='https://app.useplunk.com/subscribe/ID'>here</a> to confirm your email.</p>",
    }),
});

import requests
 
requests.post(
    "https://api.useplunk.com/v1/send",
    headers={
        "Content-Type": "application/json",
        "Authorization": "Bearer SECRET_KEY"  # Put your API key here
    },
    json={
        "to": "hello@useplunk.com",
        "subject": "Please confirm your email",
        "body": "<h1>Confirm your email</h1><p>Click <a href='https://app.useplunk.com/subscribe/ID'>here</a> to confirm your email.</p>",
    },
)

curl --location --request POST 'https://api.useplunk.com/v1/send' \\
--header 'Authorization: Bearer SECRET_KEY' \\
--header 'Content-Type: application/json' \\
--data-raw '{"to": "hello@useplunk.com", "subject": "Please confirm your email", "body": "<h1>Confirm your email</h1><p>Click <a href='https://app.useplunk.com/subscribe/ID'>here</a> to confirm your email.</p>"}'

<?php
$client = new Client();
 
$request = new Request('POST', 'https://api.useplunk.com/v1/send', ['Authorization' => 'Bearer SECRET_KEY', 'Content-Type' => 'application/json'], '{
    "to": "hello@useplunk.com",
    "subject": "Please confirm your email",
    "body": "<h1>Confirm your email</h1><p>Click <a href='https://app.useplunk.com/subscribe/ID'>here</a> to confirm your email.</p>",
}');
 
$res = $client->sendAsync($request)->wait();

require "uri"
require "json"
require "net/http"
 
url = URI("https://api.useplunk.com/v1/send")
https = Net::HTTP.new(url.host, url.port)
https.use_ssl = true
request = Net::HTTP::Post.new(url)
 
request["Authorization"] = "Bearer SECRET_KEY" # Put your API key here
request["Content-Type"] = "application/json"
 
request.body = JSON.dump({
    "to": "hello@useplunk.com",
    "subject": "Please confirm your email",
    "body": "<h1>Confirm your email</h1><p>Click <a href='https://app.useplunk.com/subscribe/ID'>here</a> to confirm your email.</p>",
})
 
response = https.request(request)

Last updated on January 23, 2023

Linking data to contacts Using your own domain