# Changed Elements The Changed Elements API provides consumers with the elements that have changed in an iModel between two changesets. Operations Include: - [Create Comparison Job](operations/create-comparison-job/) Creates a comparison. The comparison will be queued when first created and will progress to completion. When completed, it will contain all the comparison info. Use [Get Comparison Job](operations/get-comparison-job/) for information on comparison. - [Delete Comparison Job](operations/delete-comparison-job/) Deletes all stored data relating to comparison. - [Get Comparison Job](operations/get-comparison-job/) Gets comparison based on the job id. The comparison will contain the job status, start and end changeset ids, and comparison progress. If the comparison is complete, the response will also include a href to the comparison information.

Forms Service View, create, and edit details of forms that have been filled out for an iTwin/project, as well as their comments, attached files, and change history. Full CRUD functionality is available for form data, with form definitions being available in a read-only context. Note that throughout this API the terms "form" (by itself) and "form data" both refer to the same thing: data collected from users (generally entered into controls of a UI, or programmatically generated). By contrast, a "form definition" is a piece of metadata connected to form data instances. It determines the "type" of form that is filled out, and in applications that support custom form layouts, it determines how the controls are placed in the user interface. Form definitions should be added, imported, and customized by project administrators through the Bentley Form Manager web application; they cannot be modified using this API. The app can be found at https://connect-formmanager.bentley.com/designer/#/your-itwin-id (replace `your-itwin-id` with the ID of the actual iTwin or project whose form definitions you want to customize). ## Limits All API calls that return a list of results will return a maximum of 50 results. Some endpoints support a `$top` parameter to specify a number of results to retrieve (up to the maximum) and a `continuationToken` parameter to continue paging through results, allowing access to results beyond the first 50. These parameters will be included in the documentation for those endpoints. Clients with a Developer, Partner, or Integrator subscription will be limited to 5000 requests per minute. Clients with a Trial subscription will be limited to 500 requests per minute.

Issue Service View, create, and edit details of issues that have been raised in an iTwin or project, as well as their comments, attached files, and change history. Retrieval of form definitions (which define how to display an issue in an interactive UI) is also supported, though customization of them is not, and should be done by a project administrator through the CONNECT Issues web application, if needed. This form-editing app can be found at https://connect-formmanager.bentley.com/designer/#/your-itwin-id where `your-itwin-id` is replaced by the ID of the iTwin or project you're creating custom forms for. ## Limits All API calls that return a list of results will return a maximum of 50 results. Some endpoints support a `$top` parameter to specify a number of results to retrieve (up to the maximum) and a `continuationToken` parameter to continue paging through results, allowing access to results beyond the first 50. These parameters will be included in the documentation for those endpoints. Clients with a Developer, Partner, or Integrator subscription will be limited to 5000 requests per minute. Clients with a Trial subscription will be limited to 500 requests per minute.