Example
{
  "meta": {
    "requestId": "req_2c9a0jf23l4k567"
  },
  "error": {
    "detail": "Authentication credentials were incorrectly formatted",
    "status": 401,
    "title": "Unauthorized",
    "type": "https://unkey.com/docs/api-reference/errors-v2/unkey/authentication/malformed"
  }
}

​
What Happened?

This error occurs when your request includes authentication credentials, but they are not formatted correctly. The Unkey API expects API keys to be provided in a specific format in the Authorization header. Common causes include:
  • Missing the “Bearer” prefix before your API key
  • Including extra spaces or characters
  • Using incorrect casing (e.g., “bearer” instead of “Bearer”)
  • Providing a malformed or truncated API key
Here’s an example of a request with incorrectly formatted credentials: 
# Missing the "Bearer" prefix
curl -X POST https://api.unkey.com/v1/keys.listKeys \
  -H "Content-Type: application/json" \
  -H "Authorization: unkey_YOUR_API_KEY"

​
How To Fix

To fix this error, ensure your Authorization header follows the correct format:
  1. Use the correct format: Ensure your Authorization header follows the format Bearer unkey_YOUR_API_KEY
  2. Check for extra spaces or characters: Make sure there are no invisible characters or line breaks
  3. Verify the API key format: Your Unkey API key should start with unkey_
Here’s the correctly formatted request: 
curl -X POST https://api.unkey.com/v1/keys.listKeys \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer unkey_YOUR_API_KEY"
When properly authenticated, you’ll receive a successful response like this: 
{
  "meta": {
    "requestId": "req_8f7g6h5j4k3l2m1n"
  },
  "data": {
    "keys": [
      {
        "keyId": "key_123abc456def",
        "name": "Production API Key"
      }
    ]
  }
}

​
Common Mistakes

  • Authorization header format: Must be exactly Bearer unkey_YOUR_API_KEY with a single space after “Bearer”
  • Incorrect casing: Using “bearer” instead of “Bearer”
  • API key format: Your Unkey API key should start with unkey_ and contain no spaces
  • Using wrong key type: Ensure you’re using a root key for management API calls
  • Copying errors: Check for invisible characters or line breaks that might have been copied
  • Extra characters: Including quotes or other characters around the API key
  • Truncated keys: Accidentally cutting off part of the API key when copying