If you use the VSCode IDE you can install the Accord Project (Concerto) extension to benefit from syntax highlighting, compilation, and more.
The extension supports both VSCode running on your desktop, or running within your web browser.
For example, try opening this web link: https://github.dev/accordproject/concerto-docs/blob/main/docs/test.cto to view a sample CTO file in your web browser.
Install the Extension
To install the extension select Extensions in vertical toolbar to the left of the screen and then search for Concerto and install the Accord Project (Concerto) extension.
With the extension is installed you will see syntax highlighting for CTO files:
Errors in CTO files are reported in the Problems panel (accessible by clicking the number of errors/warnings in the lower status bar):
Compile Model to Target
To generate code from a set of models, context-click (control or command) on a CTO file and select Compile Model to Target from the menu, then select the target format.