Example
{
  "meta": {
    "requestId": "req_2c9a0jf23l4k567"
  },
  "error": {
    "detail": "An identity with this external ID already exists",
    "status": 409,
    "title": "Conflict",
    "type": "https://unkey.com/docs/api-reference/errors-v2/unkey/data/identity_already_exists"
  }
}

​
What Happened?

This error occurs when you’re trying to create an identity with an external ID that already exists in your Unkey workspace. External IDs must be unique within a workspace to avoid confusion and maintain data integrity. Common scenarios that trigger this error:
  • Creating an identity with an external ID that’s already in use
  • Re-creating a previously deleted identity with the same external ID
  • Migration or import processes that don’t check for existing identities
  • Duplicate API calls due to retries or network issues
Here’s an example of a request that would trigger this error: 
# Attempting to create an identity with an external ID that already exists
curl -X POST https://api.unkey.com/v2/identities.createIdentity \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer unkey_YOUR_API_KEY" \
  -d '{
    "externalId": "user_123",
    "meta": {
      "name": "John Doe",
      "email": "john@example.com"
    }
  }'

​
How To Fix

When you encounter this error, you have several options:
  1. Use a different external ID: If creating a new identity, use a unique external ID
  2. Update the existing identity: If you want to modify an existing identity, use the update endpoint instead
  3. Get the existing identity: If you just need the identity information, retrieve it rather than creating it
  4. Implement upsert logic: Use a get-or-create pattern in your code
Here’s how to update an existing identity: 
curl -X POST https://api.unkey.com/v1/identities.updateIdentity \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer unkey_YOUR_API_KEY" \
  -d '{
    "externalId": "user_123",
    "meta": {
      "name": "John Doe",
      "email": "updated_email@example.com"
    }
  }'
Or implement a get-or-create pattern in your code: 
// Pseudocode for get-or-create pattern
async function getOrCreateIdentity(externalId, meta) {
  try {
    // Try to create the identity
    return await createIdentity(externalId, meta);
  } catch (error) {
    // If it already exists (409 error), get it instead
    if (error.status === 409) {
      return await getIdentity(externalId);
    }
    // Otherwise, rethrow the error
    throw error;
  }
}

​
Common Mistakes

  • Not checking for existing identities: Failing to check if an identity already exists before creating it
  • Retry loops: Repeatedly trying to create the same identity after a failure
  • Case sensitivity: Not accounting for case sensitivity in external IDs
  • Cross-environment duplication: Using the same external IDs across development and production environments