How to create an account and log in

Intro

Create Omnisend accounts for your merchants and log them in — all via API. This guide walks through the partner integration flow: obtaining an access token, creating an account, and establishing a login session.

See API reference: Accounts

Prerequisites

• OAuth client credentials (client_id and client_secret) — contact Omnisend to obtain partner credentials
• Your platform must be registered as an Omnisend partner

Step 1: Get an access token

Request an access token using the OAuth 2.0 client credentials grant. Include the scopes you need for the operations you plan to perform.

curl --request POST \
     --url 'https://app.omnisend.com/oauth2/token' \
     --header 'Content-Type: application/x-www-form-urlencoded' \
     --data-urlencode 'client_id=YOUR_CLIENT_ID' \
     --data-urlencode 'client_secret=YOUR_CLIENT_SECRET' \
     --data-urlencode 'grant_type=client_credentials' \
     --data-urlencode 'scope=accounts.write sessions.write'

Response:

{
  "access_token": "YOUR_ACCESS_TOKEN",
  "expires_in": 7200,
  "token_type": "Bearer",
  "scope": "accounts.write sessions.write"
}

Note: The access token expires after 2 hours (expires_in: 7200 seconds). Request a new token when the current one expires.

Available scopes

Step 2: Create an account

Create a new Omnisend account with business details, a primary user, and an address. Save the returned accountID, brandID, and userID — you will need them to log the user in.

curl --request POST \
     --url https://api.omnisend.com/api/accounts \
     --header 'Authorization: Bearer YOUR_ACCESS_TOKEN' \
     --header 'Content-Type: application/json' \
     --data '{
  "name": "My Store",
  "website": "https://www.mystore.com",
  "timezone": "Europe/Vilnius",
  "currency": "EUR",
  "language": "en",
  "user": {
    "email": "[email protected]",
    "firstName": "Jane",
    "lastName": "Smith"
  },
  "address": {
    "countryCode": "US",
    "stateCode": "CA",
    "city": "San Francisco",
    "address": "123 Market St.",
    "postCode": "94105"
  }
}'

Response (201 Created):

{
  "accountID": "60a6170920d91c215e949b5a",
  "brandID": "60a6170920d91c215e949b5c",
  "userID": "60a6170920d91c215e949b5d"
}

Warning: If countryCode is US, the stateCode field is required. Omitting it returns a 400 validation error.

Field validations

Step 3: Create a login token

From your backend, request a one-time login token using the brandID and userID from account creation:

curl --request POST \
     --url https://api.omnisend.com/api/sessions/token \
     --header 'Authorization: Bearer YOUR_ACCESS_TOKEN' \
     --header 'Content-Type: application/json' \
     --data '{
  "brandID": "60a6170920d91c215e949b5c",
  "userID": "60a6170920d91c215e949b5d"
}'

Response:

{
  "token": "ONE_TIME_LOGIN_TOKEN"
}

Note: The login token is single-use. Generate a new token each time you want to log the user in.

Step 4: Log the user in

From your frontend, POST the login token to the sessions endpoint. This must happen in the user's browser so that session cookies are properly set.

Submit a form POST (or use JavaScript to submit a form) to https://api.omnisend.com/api/sessions:

<form method="POST" action="https://api.omnisend.com/api/sessions">
  <input type="hidden" name="token" value="ONE_TIME_LOGIN_TOKEN" />
  <input type="hidden" name="returnUrl" value="https://app.omnisend.com/" />
  <button type="submit">Open Omnisend</button>
</form>

On success, the user is redirected to Omnisend with active session cookies.

Note: The True-Client-IP header with the end user's IP address and a valid User-Agent header are required. Most browsers and HTTP clients set User-Agent automatically.

Step 5: Update brand information (optional)

After account creation, you can update the brand's name, website, timezone, or address. Obtain an access token with the brands.write scope, then send a PATCH request with only the fields you want to change:

curl --request PATCH \
     --url https://api.omnisend.com/api/brands/current \
     --header 'Authorization: Bearer YOUR_ACCESS_TOKEN' \
     --header 'Content-Type: application/json' \
     --data '{
  "name": "Updated Store Name",
  "timezone": "America/New_York"
}'

Response: 204 No Content

Complete flow summary

1. Get access token → POST https://app.omnisend.com/oauth2/token (client credentials)
2. Create account → POST https://api.omnisend.com/api/accounts (save brandID, userID)
3. Create login token → POST https://api.omnisend.com/api/sessions/token (from backend)
4. Log user in → POST https://api.omnisend.com/api/sessions (from browser)
5. Update brand (optional) → PATCH https://api.omnisend.com/api/brands/current