Overview
The Cobalt API lets your own systems, such as a CRM or booking tool, add subscribers automatically. You either tell Cobalt the person already agreed to receive texts, or ask Cobalt to text them a confirmation first. API access is included with the Pro and Enterprise plans.
Get Started
1. Go to Settings > API Keys and click Create API key. Only account owners and admins can create keys.
2. Enter a Name, read the Consent agreement, and tick I agree, then click Create key.
3. Click Copy and save your key somewhere safe before you click Done. Cobalt shows it only once.
4. From your system, send a POST request to the Base URL from the API Keys page followed by /subscribers. Add the header Authorization: Bearer followed by your key. In the request, send:
phone: The person's US or Canadian phone number.
existing: true if the person already agreed to receive texts from you, false if they are new.
opt_in_sms: true when existing is false. Cobalt refuses a new person without it.
name, email and external_id: Optional details to save on the subscriber.
attributes: Optional custom fields, up to 50 per request.
What happens next
Existing is true: the person is subscribed right away and Cobalt sends no text. The consent agreement you accepted covers them.
Existing is false and opt_in_sms is true: Cobalt texts them "Reply Y to subscribe to recurring automated marketing msgs" from your SMS number. They become a subscriber only when they reply Y or YES within 7 days.
Helpful Information
Someone who opted out cannot be added with existing set to true. Send existing false and opt_in_sms true so they can subscribe again by replying Y.
Numbers outside the US and Canada return "Cobalt can only text numbers in the US and Canada."
Each key allows 300 requests per minute. Cobalt sends up to 100 confirmation texts per hour. You can have up to 10 active keys.
Before You Go
Use external_id: Send your own customer ID to match each subscriber to your records.
Name keys by system: A name like CRM shows which key to revoke if you stop using that system.
Check first: Existing true skips the confirmation text, so use it only for people who already agreed.
Get support
Questions? Please message our team via Live Chat on the bottom right or send us a text message at: 321-318-9777