Getting Started With Your API

This article provides step-by-step setup instructions to get started to use the API endpoints and send emails to your users.

If you use PHP, you can install our library – Sendios-SDK.

Before sending emails, you need to do the following:

  1. Configure Sender and Tracking Domains;

Setting up a Tracking Domain is optional: use it if you need to track email opens and link clicks.

  1. Configure SPF/DKIM records according to Sender Domain Settings;
  2. Create a Project;
  3. Create a template;
  4. Create a transactional email.

All API points work asynchronously. If you get a 200 OK response, we received and processed your request, which was validated. To find out the email sending status, go to the admin panel to the User profile or Webhooks. sections.

Authorization is required to make requests to the server. The following steps should be performed:

  1. Request clientId and API key from your Customer Success Manager;
  2. Encode the string {clientId}:{api_key} in base64;
  3. Enter the received coded string into the authorization header.
clientIdClient identifier
api_keyAPI key
curl -X GET \
-u {clientId}:{api_key}

If you use our Sendios SDK library, you must request the clientId and SDK key from the Customer Success Manager.


Currently, only the PHP SDK is supported, and other programming languages are unavailable.

You can find out about the system's status on the website there, in case of any incidents or system unavailability, we notify about problems and publish actual information. More options for monitoring can be found in the article Sendios Monitoring.

Useful API endpoints

  • User registration in the Sendios database is initiated through the dedicated API endpoint Send system / trigger email when sending the first system email, such as "Welcome". When using this API endpoint provide user information (including email address and additional details like country, name, language, gender, age, etc., within the "user" array) and variables for the email content (if necessary, within the "data" array).
  • To create a user without sending an email, you can use the API endpoint Create omnichannel user. When using this API endpoint, you can immediately add any parameters in the "fields" array to pass user-specific information that is unique to your product.
  • To add or update user information, that is unique to your product, for the user already created in the system, utilize the API endpoints Add and update user data by project ID and email and Add and update user data by user_id.
  • To facilitate analytics collection, it is essential to pass payment details to the corresponding API endpoint Add user payments.
  • After deleting a user account on the product or unsubscribing from the settings page, it is necessary to unsubscribe the user through the related API endpoint Unsubscribe.
  • Via the API endpoint Erase user you can add a user to the deletion queue. As a result, the user will be deleted after 2 days. This is a separate functionality to comply with GDPR.