# Step 3 (Optional): Config the app login-free process
After the custom app is created on the open platform, the corresponding web project can be developed locally. If you want the application to be accessed in the Feishu client, you can obtain the information of the logged-in user of the client to realize the non-login access to the application, you can configure the non-login process for the application. This article mainly introduces the workflow of applying Banban, and common problems related to implementing the [requestAuthCode](https://open.feishu.cn/document/uYjL24iN/uUzMuUzMuUzM/20220308) interface of Banyan.
**Sample code**
Regarding how to implement application free login in web projects, the open platform provides corresponding web app development tutorials. The development tutorial contains complete web app sample codes. You can view the code introduction and experience the development process, so as to help you understand and use the application free login capability. For details, see [Web App Free Login](https://open.feishu.cn/document/home/quickly-create-a-login-free-web-app/introduction-to-sample-code).
## Free login process
If the user has already logged in to the Feishu client, they can directly access the web app in the client without having to log in again. During the actual development of the application, you can obtain the information of the logged-in user through the following flow chart.
Flow Description:
- The App ID and App Secret in the above figure are the only input information required for the entire process.
App ID and App Secret parameters are located in [Developer Console](https://open.feishu.cn/app) on the details page of the app **Credentials & Basic Info**.
- In the figure above, the data exchange between the Feishu client and the access server and the authentication center is completed through HTTP requests.
Step numbers involving data exchange: 1~2, 4~5, 8~9, 10~11.
- In the above figure, the data exchange between the front end of the access side and the Feishu client (step number: 3~6) is completed through JSAPI calls.
- The data exchange between the front-end of the access party and the server of the access party in the above figure (step number: 7, 12) is completed within the framework of your web app.
The web app **front-end** needs the cooperation of the **server** to realize the free login process. It is recommended that you reasonably arrange for front-end and server-side developers to participate together.
## requestAuthCode interface error code
The [requestAuthCode](https://open.feishu.cn/document/uYjL24iN/uUzMuUzMuUzM/20220308) interface is used to obtain the authorization code for the web app without login, which is convenient for the web app to realize the process of the user without login. The `fail` return object of the interface contains [errCode attribute](https://open.feishu.cn/document/uYjL24iN/ukzNy4SO3IjL5cjM) (error code and error message). When you are actually opening, the corresponding troubleshooting suggestions for interface error codes are shown in the table below.
error code | Description | Troubleshooting suggestions
---|---|---
10236 | URL is invalid.
The URL is empty, or the URL of the current page is not configured in the **Security Settings > Redirect URLs** list of the application details page of [Developer Console](https://open.feishu.cn/app). | Check whether the URL of the current page has been configured in the app details page **Security Settings > Redirect URLs** of [Developer Console](https://open.feishu.cn/app). If not configured, you need to configure the redirection URL and try again.
If this error code still occurs after configuring the URL, it is because the page you call the [requestAuthCode](https://open.feishu.cn/document/uYjL24iN/uUzMuUzMuUzM/20220308) interface is not in the redirection URL list. It is recommended to check the full path of the URL of the current page (excluding the part after `?` and `#`), whether it has been configured in the application details page **Security Settings > Redirect URLs** in the developer consle, if not configured, You need to configure the redirection URL and try again.
- (Suggestion) How to get the URL of the current page: call `window.location.href.split('?')[0].split('#')[0]` on the current page to get the URL.
The full path of the URL corresponding to the application home page is the domain name plus a slash, and the path can be verified by calling `window.location.href.split('?')[0].split('#')[0]`. For example, the domain name `https://open.feishu.cn` or the domain name `http://127.0.0.1:3000` (IP address + port number), if the corresponding homepage needs to obtain the Authorization Code, the redirection that should be filled in The URLs are `https://open.feishu.cn/` and `http://127.0.0.1:3000/` respectively.
- When filling in the redirection URL, examples and descriptions of common situations are shown in the figure below.
10235 | The redirect URL is not configured in the developer backend. | Check whether the URL of the current page has been configured on the application details page **Security Settings > Redirect URLs** in the developer consle. If not, please configure and try again.
10200 | appid is invalid. | Please check whether the app_id passed in when the front end calls requestAuthCode is the same as the App ID you obtained from the **Credentials & Basic Info** on the application details page in the developer consle. If different, keep the same and try again.
10228 | The application is not visible to this user. | Find the version with the status of **Released** in the application details page **Version Management & Release** in the developer consle, view the version details, and check whether the **Availability** includes the current user.
10232 | Failed to obtain the temporary authorization code without login. | It is recommended to open the page again and try calling.
10234 | Failed to get the application details page **Security Settings > Redirect URLs** list in the developer consle. | It is recommended to open the page again and try calling.
10210 | sessionid is invalid. | It is recommended to log out of the current account and try to call after logging in again.