Bulk create/update customer

API at a glance

Description: This API creates or updates multiple customers in a single request. You can process up to 50 customers per API call.

Authentication & testing

Testing the API on this page

How to try it here

Use your User API Key as the Username (leave Password blank).

Select the appropriate API endpoint based on your Blueshift region.

Enter the necessary parameters and click Try It to run the request.

Authentication using Base64 encoding

Note for developers

API requests require authentication using HTTP Basic Authentication with an API key. The API key serves as the username, while the password field should be left empty. The format to encode is: your_api_key: (note the trailing colon).

This string must be Base64-encoded and included in the request's Authorization header as follows:

Authorization: Basic encoded_value

You can generate the encoded value using a trusted Base64 encoder.

Postman collection

Try it with Postman: Explore the API using Blueshift's Postman collection.

Things to know before you start

Batch limit: Maximum 50 customers per API call.
Rate limit: We recommend limiting bulk calls to 5 per second (or 250 users per second).
CRITICAL - Required identifier: Each customer object MUST have either email or customer_id. Without at least one valid identifier, the customer record will not be created or updated. Always ensure you provide valid identifiers to avoid data loss.
⚠️ WARNING - Check response carefully: Even if the API returns 200 OK, individual customer records can fail if they're missing identifiers. The failed records will appear in the errors array with user_identifier_missing error. Always validate your response to ensure all customers were processed successfully.
Use case: Best for bulk customer imports, batch profile updates, data migrations, and syncing customer data from external systems.

Request parameters

Check out the request parameters

Body parameters

Parameter	Type	Required	Description
`customers`	`array`	✅ Yes	Array of customer objects. Maximum 50 per request.

Customer object fields

Parameter	Type	Required	Description
`email`	`string`	✅ Yes (or customer_id)	Email address of the customer (max 64 characters).
`customer_id`	`string`	✅ Yes (or email)	Customer ID of the customer.
`firstname`	`string`	❌ No	First name of the customer.
`lastname`	`string`	❌ No	Last name of the customer.
`uuid`	`string`	❌ No	UUID of the customer (for updates).
`subscription_groups`	`array`	❌ No	User's subscription preferences. See structure below.

Subscription groups object

Parameter	Type	Required	Description
`id`	`string`	✅ Yes	ID of the subscription group.
`subscribed`	`boolean`	✅ Yes	`true` if subscribed, `false` if unsubscribed.

Example requests & responses

Bulk create/update customers (Success)

{
  "customers": [
    {
      "email": "[email protected]",
      "firstname": "John",
      "lastname": "Smith"
    },
    {
      "email": "[email protected]",
      "firstname": "Jane",
      "lastname": "Doe"
    },
    {
      "email": "[email protected]",
      "customer_id": "CUST-12345",
      "firstname": "Mike",
      "lastname": "Johnson"
    },
    {
      "customer_id": "CUST-67890",
      "firstname": "Sarah",
      "lastname": "Williams"
    },
    {
      "customer_id": "CUST-11223",
      "email": "[email protected]",
      "firstname": "Robert",
      "lastname": "Brown"
    }
  ]
}

{
  "customers": [],
  "errors": []
}

⚠️ Error: Missing identifier (200 OK with errors)

What happens: API returns 200 OK, but customers without valid identifiers fail and appear in the errors array.

{
  "customers": [
    {
      "email": "[email protected]",
      "firstname": "John"
    },
    {
      "customer_id": "CUST-12345",
      "lastname": "Doe"
    },
    {
      "lastname": "Williams"
    }
  ]
}

{
  "customers": [
    {
      "lastname": "Williams",
      "customer_id": null
    }
  ],
  "errors": [
    {
      "status": 400,
      "error_data": {
        "user_identifier_missing": [
          "No valid identifier found"
        ]
      }
    }
  ]
}

Prevention: Always include either email or customer_id for every customer in your request.

API error responses

Note
The following error codes are commonly returned by Blueshift APIs. Depending on the specific endpoint, not all may apply.

Status code	Description	Example responses
400 Bad Request	The request is invalid due to missing or incorrect parameters. This includes missing fields, invalid values, formatting issues, or conflicts such as duplicate data.	`{ "errors": { "name": ["can't be blank"] } }` `{ "errors": { "startdate": ["can't be blank"] } }`
401 Unauthorized	API authentication failed due to an invalid or missing API key.	`{ "message": "Not authorized" }`
403 Forbidden	The API key does not have sufficient permissions to perform this action.	`{ "message": "Permission denied" }`
404 Not Found	The specified campaign was not found. Verify the campaign UUID.	`{ "message": "Campaign not found" }`
422 Unprocessable Entity	The campaign cannot be paused due to its current status (e.g., already completed or archived). One or more scheduling parameters may be invalid (if applicable).	`{ "message": "Campaign cannot be paused in its current status." }` `{ "message": "Invalid schedule values" }`
429 Too Many Requests	The request limit has been exceeded. Reduce request frequency.	`{ "message": "Rate limit exceeded" }`
500 Internal Server Error	An unexpected server error occurred. Contact support if the issue persists.	`{ "message": "Internal Server Error - Please contact support for more information." }`
502 Bad Gateway	The server received an invalid response. Retry the request.	`{ "message": "Bad Gateway - Please retry the request." }`
503 Service Unavailable	The service is temporarily unavailable. Try again later.	`{ "message": "Service Unavailable - The service is temporarily unavailable. Try again later." }`
504 Gateway Timeout	The server took too long to respond. Retry the request with exponential backoff.	`{ "message": "Gateway Timeout - The server took too long to respond. Retry with exponential backoff." }`