Accounts

Intro

Endpoint: https://api.omnisend.com/api/accounts

Guide: How to create an account and log in

The Accounts API lets partners programmatically create Omnisend accounts, log users into Omnisend, and update brand information. It is designed for platform integrations that manage merchant onboarding and single sign-on flows on behalf of their users.

Authentication

All endpoints require an OAuth 2.0 access token obtained via the client credentials grant:

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'

Note: Access tokens expire after 2 hours. Request a new token when the current one expires.

OAuth scopes

Scope	Description
accounts.write	Create accounts
brands.write	Update brand information
sessions.write	Create login tokens / sessions

Request only the scopes you need. For example, account creation requires accounts.write; updating a brand requires brands.write.

Field Validations

Account creation

Field	Required	Validation
name	Yes	2–200 characters, no XSS, no URLs
website	Yes	Valid URL format
timezone	Yes	IANA Time Zone name (e.g. `Europe/Vilnius`)
currency	Yes	ISO 4217 code (e.g. `EUR`, `USD`)
language	Yes	BCP 47 language tag (e.g. `en`)
user.email	Yes	Valid email, max 100 characters
user.firstName	Yes	2–50 characters, no XSS, no URLs
user.lastName	Yes	2–50 characters, no XSS, no URLs
user.phone	No	4–20 characters, no XSS, no URLs
address.countryCode	Yes	ISO 3166-1 alpha-2 (e.g. `US`, `LT`)
address.stateCode	Conditional	Required when `countryCode` is `US`. Exactly 2 letters
address.city	Yes	2–50 characters, no XSS, no URLs
address.address	Yes	5–100 characters, no XSS, no URLs
address.postCode	Yes	2–20 characters, no XSS, no URLs

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

Brand update

All fields in the brand update request are optional — include only the fields you want to change. When providing an address object, at least one address field must be non-empty.

Error Responses

Errors follow RFC 9457 Problem Details format:

{
  "type": "https://api-docs.omnisend.com/reference/responses",
  "title": "Bad Request",
  "detail": "Validation failed",
  "status": 400,
  "errors": [
    {
      "field": "address.stateCode",
      "code": "required",
      "message": "state code required for US"
    }
  ]
}

Status	Description
400	Validation error — check the `errors` array
403	Invalid or missing credentials
404	Resource not found (brand update only)
412	User email already exists (account creation only)

Example: Create Account

curl --request POST \
     --url https://api.omnisend.com/api/accounts \
     --header 'Authorization: Bearer YOUR_ACCESS_TOKEN' \
     --header 'Content-Type: application/json' \
     --data '{
  "name": "Omnisend",
  "website": "https://www.omnisend.com",
  "timezone": "Europe/Vilnius",
  "currency": "EUR",
  "language": "en",
  "user": {
    "email": "[email protected]",
    "firstName": "John",
    "lastName": "Doe"
  },
  "address": {
    "countryCode": "US",
    "stateCode": "FL",
    "city": "Los Angeles",
    "address": "33 W. Prairie St.",
    "postCode": "90034"
  }
}'

Response (201 Created):

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

Example: Update Brand

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 Name",
  "timezone": "America/New_York",
  "address": {
    "countryCode": "US",
    "stateCode": "NY",
    "city": "New York",
    "address": "123 Broadway",
    "postCode": "10001"
  }
}'

Response: 204 No Content