JSON is a data interchange format that is widely used in web applications to exchange data between client-side and server-side components. While JSON itself is not inherently secure or insecure, there are best practices you can follow to ensure the security of your JSON data in your web application:

1. Validate input data: Ensure that the JSON data received from external sources is validated and sanitized before processing it in your application. Use techniques such as input validation and output encoding to prevent injection attacks.

2. Use HTTPS: Use HTTPS to secure the transmission of JSON data between client and server. HTTPS provides encryption and authentication of data exchanged between the client and the server, preventing interception and tampering by third parties.

3. Use CORS: Implement Cross-Origin Resource Sharing (CORS) to restrict access to JSON data from unauthorized domains. CORS is a security feature that allows servers to specify which domains can access their resources, thereby preventing cross-site scripting (XSS) attacks.

4. Minimize data exposure: Only expose the minimum amount of data required for the application to function. Avoid exposing sensitive data such as passwords, user data, and authentication tokens in JSON data.

5. Use whitelisting instead of blacklisting: Instead of trying to block known malicious inputs, implement a whitelist of allowed inputs. This reduces the likelihood of new or unknown threats being introduced into your application.

6. Avoid using eval(): Avoid using eval() to parse JSON data, as it can lead to security vulnerabilities. Instead, use JSON.parse() to safely parse JSON data into a JavaScript object.

7. Secure storage: Ensure that any JSON data stored on the client-side is encrypted and stored securely to prevent unauthorized access.

Following these best practices can help you ensure the security of your JSON data in your web application.