Add contacts from any app with one API call
Send a contact into ConvertNow from a checkout, form tool or script. One request with your API key adds the person and puts them on the lists you choose.
Start freeSee the stepsThe ConvertNow contacts endpoint adds or updates a contact and adds them to your lists with a single authenticated request. Use it when a tool you use has no ConvertNow integration yet.
It is built for developers and for no-code users who can send a webhook or HTTP request from their tool.
Step by step
Five steps from API key to first contact.
Create an API key
In ConvertNow, open the Email API page and, on the API Keys tab, create a key. Give it a name such as Checkout.
Copy the key
It starts with cn_live_ and is shown in full only once, so copy it now.
Note your list ID
Find the ID of the list the contact should join.
Send the request
POST to https://app.convertnow.co/v1/contacts with your key in the Authorization header, as shown below.
Check the response
A new contact returns status 201 with created set to true. An existing contact returns 200 with created set to false.
Request fields and limits
Only the email address is required.
| Field | Required | What it does |
|---|---|---|
| Yes | The contact's email address | |
| first_name, last_name | No | Saved on the contact and updated if they already exist |
| list_ids | No | Up to 20 list IDs to add the contact to (list_id takes a single one) |
Contacts who unsubscribed, bounced or complained are never re-subscribed
600 requests a minute per key
Wrong or missing key returns 401, an invalid email returns 400
A list that is not yours returns 404
Frequently asked questions
What does the endpoint do if the contact already exists?
It updates their name if you send one, adds them to the lists you named, and returns created set to false.
Can it re-subscribe someone who unsubscribed?
No. Unsubscribed, bounced and complained contacts are never re-subscribed through this endpoint.
Can I use it from Zapier or Make?
Yes, any tool that can send an HTTP POST with a header can call it.
Is there a rate limit?
Yes, 600 requests a minute per API key.
Related integrations
Push contacts in from anywhere
One request, your key, and the contact is on your list.
Start free at convertnow.co