How can you secure your front-end requests with JSON Web Tokens?

1 What are JWTs?

JWTs are compact and self-contained strings that consist of three parts: a header, a payload, and a signature. The header contains information about the algorithm and the type of token. The payload contains the claims, or the data that you want to transmit and verify, such as the user ID, the expiration time, or the roles. The signature is a cryptographic hash that ensures the integrity and authenticity of the token. The three parts are separated by dots and encoded in base64.

2 How do JWTs work?

JWTs work by using a secret key or a pair of keys (one public and one private) to sign and verify the tokens. The sender of the token uses the secret key or the private key to generate the signature, and the receiver of the token uses the same secret key or the public key to validate the signature. If the signature matches, the token is valid and the claims can be trusted. If the signature does not match, the token is invalid and the request is rejected.

3 How to use JWTs in your front-end?

To use JWTs in your front-end, you should obtain a JWT from the server or API that you want to communicate with, and store it securely. This is usually done when the user logs in or registers. Different methods of storage can be used, such as local storage, session storage, cookies, or memory; however, you should be aware of the associated risks. Additionally, the JWT should be sent with every request that requires authorization. The standard practice is to use the Authorization header with the Bearer scheme. Lastly, you should handle the JWT expiration and renewal by checking its expiration time and requesting a new one before it expires. Different strategies can be used for this purpose, such as using a refresh token, a sliding window, or a short-lived token.

4 What are the benefits of using JWTs?

Using JWTs for front-end development offers several advantages, such as simplicity and scalability. Generating and validating JWTs does not require any state or database on the server side, making them suitable for distributed and microservices architectures. Moreover, JWTs are also flexible and extensible, as they can carry any JSON compatible data with a size limit. Furthermore, JWTs provide performance and efficiency due to their compactness and speed of transmission, as well as eliminating additional network requests or database queries for authentication and authorization.

5 What are the challenges of using JWTs?

Using JWTs has some challenges and drawbacks that should be taken into account, such as security and privacy. Since JWTs are not encrypted but encoded, anyone with access to the token can read its contents. Thus, it is essential to protect the token from theft or tampering, and not store sensitive or personal data in the token. Additionally, JWTs are stateless, making them difficult to revoke or invalidate once they are issued. Furthermore, JWTs are larger than other types of tokens, which can affect performance and storage of your web application. Lastly, you should consider the compatibility of the browsers and libraries you use, as not all of them may support the features and standards of JWTs.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?