To encrypt API request, response, and header parameters to ensure they are not readable in the client’s browser source code, you can implement encryption techniques such as HTTPS (SSL/TLS) for secure communication between the client and server. By using HTTPS, the data transmitted between the client and server is encrypted, making it unreadable to anyone intercepting the traffic.

Additionally, you can encrypt sensitive data within the request payload using encryption algorithms like AES (Advanced Encryption Standard) or RSA (Rivest-Shamir-Adleman) before sending it to the server. On the server-side, decrypt the encrypted data to process the request securely.

Remember to handle encryption and decryption securely on both the client and server sides to maintain data confidentiality and integrity.