Replace User ID | Appizer API Documentation

Replace a user's ID with a new identifier across all records.

Endpoint

POST /users/replace-id

Authentication

Required: Bearer token in Authorization header

Authorization: Bearer YOUR_API_KEY

Request Body

{
  "user_id": "user_123",
  "new_user_id": "user_456"
}

Parameters

Parameter	Type	Required	Description
`user_id`	string	Yes	Current user identifier
`new_user_id`	string	Yes	Desired new identifier

Response

{
  "success": true,
  "user_id": "user_456",
  "message": "User ID updated"
}

Examples

JavaScript

const response = await fetch('https://api.appizer.com/v1/users/replace-id', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    user_id: 'user_123',
    new_user_id: 'user_456'
  })
});

const data = await response.json();
console.log(data);

Python

import requests

response = requests.post(
    'https://api.appizer.com/v1/users/replace-id',
    headers={
        'Authorization': 'Bearer YOUR_API_KEY',
        'Content-Type': 'application/json'
    },
    json={
        'user_id': 'user_123',
        'new_user_id': 'user_456'
    }
)

print(response.json())

cURL

curl -X POST https://api.appizer.com/v1/users/replace-id \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "user_id": "user_123",
    "new_user_id": "user_456"
  }'

Error Responses

Status Code	Description
400	Bad Request - Invalid request body or missing required fields
401	Unauthorized - Invalid or missing API key
404	Not Found - User ID does not exist
409	Conflict - New user ID already exists
429	Too Many Requests - Rate limit exceeded
500	Internal Server Error - Something went wrong on our end

Important Notes

This operation updates the user ID across all historical data
All events, properties, and associations will be updated to the new ID
The old user ID will no longer be valid after this operation
Consider using Create User Alias if you need to maintain both IDs

Use Cases

ID Format Changes: Update IDs to match new system requirements
User Merging: Consolidate duplicate user profiles
System Refactoring: Align user IDs with new architecture

Best Practices

Verify the new_user_id doesn't already exist before replacing
Update your application's user ID references before making this API call
Consider the impact on historical data and reports
Use aliases instead if you need to maintain backward compatibility
Document ID changes for audit purposes