In this blog I will discuss how does Accounts handle the incoming request to reset the password. If a user forgets his/her password, They can use forgot password button on http://accounts.susi.ai and It’s implementation is quite straightforward. As soon as a user enter his/her e-mail id and hits RESET button, an ajax call is made which first checks if the user email id is registered with SUSI.AI or not. If not, a failure message is thrown to user. But if the user is found to be registered in the database, An email is sent to him/her which contains a 30 characters long token. On the server token is hashed against the user’s email id and a validity of 7 days is set to it. Let us have a look at the Reset Password link one receives. http://accounts.susi.ai/?token={30 characters long token} On clicking this link, what it does is that user is redirected to http://accounts.susi.ai with token as a request parameter. At the client side, A search is made which evaluates whether the URL has a token parameter or not. This was the overview. Since, http://accounts.susi.ai is based on ReactJS framework, it is not easy alike the native php functionality, but much more logical and systematic. Let us now take a closer look at how this parameter is searched for, token extracted and validated. As you can see http://accounts.susi.ai and http://accounts.susi.ai/?token={token}, Both redirect the user to the same URL. So the first task that needs to be accomplished is check if a parameter is passed in the URL or not. First import addUrlProps and UrlQueryParamTypes from react-url-query package and PropTypes from prop-types package. These will be required in further steps. Have a look at the code and then we will understand it’s working. const urlPropsQueryConfig = { token: { type: UrlQueryParamTypes.string }, }; class Login extends Component { static propTypes = { // URL props are automatically decoded and passed in based on the config token: PropTypes.string, // change handlers are automatically generated when given a config. // By default they update that single query parameter and maintain existing // values in the other parameters. onChangeToken: PropTypes.func, } static defaultProps = { token: "null", } Above in the first step, we have defined by what parameter should the Reset Password triggered. It means, if and only if the incoming parameter in the URL is token, we move to next step, otherwise normal http://accounts.susi.ai page should be rendered. Also we have defined the data type of the token parameter to be UrlQueryParamTypes.string. PropTypes are attributes in ReactJS similar to tags in HTML. So again, we have defined the data type. onChangeToken is a custom attribute which is fired whenever token parameter is modified. To declare default values, we have used defaultProps function. If token is not passed in the URL, by default it makes it null. This is still not the last step. Till now we have not yet checked if token is there or not. This is done in the componentDidMount…