Do we store JWT token in database?
JWTs can be used as an authentication mechanism that does not require a database. The server can avoid using a database because the data store in the JWT sent to the client is safe.
Like local storage, session storage is accessible by any javascript code running on the same domain that the web application is hosted. So the only thing that changes, is that when a user closes their browser, the JWT will disappear and the user will have to login again in their next visit to your web application.
A JWT needs to be stored in a safe place inside the user's browser. Any way,you shouldn't store a JWT in local storage (or session storage). If you store it in a LocalStorage/SessionStorage then it can be easily grabbed by an XSS attack.
It depends. If you have multiple servers of keep the token between server restarts than you need to persist it somewhere. The database is usually an easy choice. If you have a single server and don't care that your users have to sign in again after a restart, than you can just keep it in the memory.
So based on the above premise - it will be best if we store JWT in Cookies. On every request to server, the JWT will be read from Cookies and added in the Authorization header using Bearer scheme. The server can then verify the JWT in the request header (as opposed to reading it from the cookies).
Because JWTs are just URL safe strings, they're easy to pass around via URL parameters, etc. They contain JSON-encoded data. This means you can have your JWT store as much JSON data as you want, and you can decode your token string into a JSON object. This makes them convenient for embedding information.
JWT is a JSON based security token forAPI Authentication
JWT is just serialised, not encrypted. OAuth is not an API or a service: it's an open standard for authorization . OAuth is a standard set of steps for obtaining a token.
Since tokens are stored in local/session storage or a client side cookie, they are open to an XSS attack getting the attacker access to the token. This is a valid concern, and for that reason you should keep your tokens expiration low. But if you think about the attack surface on cookies, one of the main ones is XSRF.
Generally speaking, this is nice, but what happens if your entire JWT is stolen? Because JWTs are used to identify the client, if one is stolen or compromised, the attacker has full access to the user's account in the same way they would if the attacker had compromised the user's username and password instead.
jwt Getting started with jwt What to store in a JWT
Registered claims like sub , iss , exp or nbf. Public claims with public names or names registered by IANA which contain values that should be unique like email , address or phone_number . See full list. Private claims to use in your own context and values can ...
Why LocalStorage is not secure?
XSS attacks allow attackers to inject client-side scripts into Web pages viewed by other users. If someone injects their own JavaScript code into your website, they can retrieve all the data stored in the LocalStorage and send it anywhere. All sensitive data stored in LocalStorage can be stolen.
Where should I store my tokens in the front-end? There are two common ways to store your tokens. The first is in localStorage and the second is in cookies. There is a lot of debate over which one is better with most people leaning toward cookies as they are more secure.

Conclusion. Both cookies and localStorage are vulnerable to XSS attacks. However, cookie-based token storage is more likely to mitigate these types of attacks if implemented securely. The OWASP community recommends storing tokens using cookies because of its many secure configuration options.
jwt Getting started with jwt What to store in a JWT
Registered claims like sub , iss , exp or nbf. Public claims with public names or names registered by IANA which contain values that should be unique like email , address or phone_number . See full list. Private claims to use in your own context and values can ...
Most guidelines, while advising against storing access tokens in the session or local storage, recommend the use of session cookies. However, we can use session cookies only with the domain that sets the cookie. Another popular suggestion is to store access tokens in the browser's memory.
sessionStorage is similar to localStorage ; the difference is that while data in localStorage doesn't expire, data in sessionStorage is cleared when the page session ends. Whenever a document is loaded in a particular tab in the browser, a unique page session gets created and assigned to that particular tab.
With cookies, the access token is still hidden, attackers could only carry out “onsite” attacks. The malicious scripts injected into the web app could be limited, or it might not be very easy to change/inject more scripts. Users or web apps might need to be targeted first by attackers.