Masking Fields

Masking fields ensures that sensitive data is masked before being sent to Treblle.

This feature is integrated into all Treblle SDKs to ensure data masking happens at the programming level before any API request leaves your server.

How It Works

• Customizable Masking: You can define which fields should be masked when integrating the SDK.

  Example: To mask a field named email, you must include it in your masking configuration.

  Any instance of the email field in your API request or response will be replaced with ***** or the equivalent number of stars.

• Replacement Mechanism: Once a field is defined for masking, all instances of that field’s value are replaced with star characters (*). The number of stars corresponds to the length of the original value.

  Example: If the username field contains the value john_doe, it will be replaced with ******** (8 stars).

• Scope of Masking: Masking is applied across:

  • Request and response headers

    Example: Masking the Authorization header will ensure sensitive tokens or keys are replaced with stars.

  • Request and response data

    Example: A credit_card field in the request payload with the value 4111111111111111 will be replaced with ****************.

  • Arrays of any depth

    Example: An array like ["123", "456"] with masked fields will become ["***", "***"].

  • Object keys and values

    Example: An object { "api_key": "abc123" } will become { "api_key": "******" }.

Example: Basic Express API

This is an example of a basic Express API where masking is applied to sensitive fields like email and phone number before sending the response.

Masking these fields ensures that their values remain hidden but retain the original length in the API response.

app.use(
    treblle({
        apiKey: process.env.TREBLLE_API_KEY,
        projectId: process.env.TREBLLE_PROJECT_ID,
        additionalFieldsToMask: ['email', 'phone_number'],
    })
);

app.post('/register', (req, res) => {
    const { email, phone_number } = req.body;
    res.status(201).json({
        message: 'User registered successfully!',
        data: { email, phone_number },
    });
});

Masked Data View in Treblle Platform

Here is an image showing how the masked data appears on Treblle’s platform. Notice that the masked fields email and phone_number are displayed with stars, matching the length of the original data.

Special Case: Authorization Header

Only the API key value is masked when masking the Authorization field.

For example:

Bearer lsGPLl4k6Vc4J0VhnFaMBqetNtn1ofsB

Will be masked as:

Bearer ********************************

This ensures you retain the authentication type and key length without exposing the API key.

Default Masked Fields

By default, the following sensitive fields are masked in all Treblle SDKs:

• password
• pwd
• secret
• password_confirmation
• passwordConfirmation
• cc
• card_number
• cardNumber
• ccv
• ssn
• credit_score
• creditScore
• api_key

Custom Masked Fields

You can define additional fields to be masked according to your your application’s requirements.

For instructions on customizing masked fields for your programming language or framework, refer to the SDK documentation in the integrations section.