REST API Overview

Value Statement: The SYNCHRO 4D Schedule API allows project data from a version 6.5 SYNCHRO 4D Control hosted project to be accessible for custom developed applications for desktop and mobile, web and single-page applications such as dashboards and machine-to-machine no UI services. Schedule data such as Tasks, Resources, Resource Statuses, Resource Groups and User Fields can be retrieved, POST Resources Status is available at release and additional POST and PATCH endpoints to be released in the future.


SYNCHRO Control hosted project must be upgraded to version 6.5 or later.

API Fundamentals


All API access is over HTTPS and is accessed from All data is sent and received as JSON.

Dates and times use ISO 8601 format.



APIs that return collections could return a partial set of results and clients need to page through the results to retrieve all of the results. Requests that return multiple items will be paginated to 100 items by default and a maximum of 10,000 items unless specified otherwise in an API operation's documentation.

User Fields

User Fields are very expansive and can be data intensive in a project, potentially containing millions of rows, this results in a performance hit to download User Field endpoints, downloading can be time consuming depending on the number of rows, for this reason to retrieve User Fields and User Field Values data an option need to be enabled in the iModel project.

Project must be  enabled on iModel.

Open SYNCHRO Control project > Administration > Manage iModel > iModel Options (Three dots) > Edit

Expand “SYNCHRO Sync Settings” > Tick “Process non-3D user fields” (Resources and Tasks) and “Process 3D user fields” (Entity3Ds) as required and click “Update” to complete.

Enabling processing of user fields will start an iModel synchronization shortly after clicking “Update”, the iModel synchronization needs to complete before the User Fields and User Field Values are available through the 4D Schedule API.