Parameters are containers that are replaced dynamically with values upon loading an AppPage. You can use them to personalize content and user experience in an application. For example, you could use a parameter to display a personalized welcome message to users based on their name or location. 

Parameter categories 

Currently, the following types of parameters are available:

• App parameters – You can create these parameters and assign values to them in the App Parameters area of your application. You can use app parameters throughout your app. Every Caspio application can have its own list of app parameters. They allow you to manage values in one central place for your entire application. For example, if your application generates a notification email, the email address can be defined as a parameter and used in all the DataParts that generate notification emails or data filters. If you need to change the email recipient, you can do it in the app parameters section of your app and the change immediately applies to all the instances of the parameters across your AppPages. Learn more about app parameters and data filters. 
• Data source fields contain all fields from the table or view that are the data source of the AppPage. You can insert them into HTML blocks and email notifications to provide a robust way to personalize screens.
• Authenticated user fields enable access to data of signed-in app users that are stored in a directory. For example, you can use app users’ ID to track which user inserted or updated a record or to filter the data to display only the information that is relevant to the logged-in user (such as a sales manager’s list of interactions with a prospect). The notation for these parameters is: [@authfield:First_Name]. A DataPart must be in the protected segment for an authenticated user field to be available. 
• DataPart fields are associated with the fields within specific DataParts: Forms orReports. These fields allow you to filter, prepopulate, or display data based on user interactions or values passed from one DataPart to another. DataPart fields enable you to create dynamic content by linking different components together. For example, if a user selects a record from a list, the corresponding details can be automatically displayed on another part of the page using the selected record's ID as a DataPart field parameter in Data filters.

• Query string parameters are a type of parameter that you can pass via the URL of an AppPage. These parameters are appended to the URL in key-value pairs. You can use them to dynamically filter data, prepopulate form fields, or drive other interactions within your application. They are especially useful for linking different AppPages or components within a page. For example, you might use a query string parameter to pass a specific record ID from a Report page to a Details/Update Form, ensuring that the relevant information based on the selected record is displayed.
  Query string parameters have similar use cases to DataPart fields. DataPart fields are saved in the user session so when the URL is copied and opened by another user, the results may be different depending on the user session parameters. When using query string parameters, an app link shared by one app user to another will always return the same results. DataPart fields are easier to maintain, so we recommend using them for building your applications unless your app users need to share the application links with each other.

• System parameters are parameters provided by Caspio that contain information about your application and your user's environment. You can use them in HTML blocks of all Form DataParts, HTML/Text DataParts, email notifications, and in the To field of the Submission and Sign-up Forms.
  Currently, the following parameters are supported: 
  • App name - Name of the app to which an AppPage belongs. 
  • Bridge server - The Caspio server URL that serves an AppPage. 
  • Browser - Part of a User Agent string. It contains only information about a browser. 
  • Client IP - IP address of the app user. It is a publicly visible IP address of the user's network. 
  • Host domain - Name of a domain where the AppPage is embedded. 
  • Host page - Part of the URL string from where the AppPage is embedded. It does not include any parameters that may be in the URL. Characters after "?" in the URL are removed. 
  • Host URL - Full URL string of the web page where the AppPage is embedded. This parameter includes the entire URL. 
  • Protocol - Protocol used by the app user to access the page (HTTP or HTTPS). 
  • Timestamp - Inserts the current server date, time, or date and time based on the time zone of a segment. 
  • User agent - Extended information about the user browser, including its name, version, and platform details.