Ever wanted to stop your code half-way through executing and see what’s going on?
Well, now you can. I’m pleased to announce that Anvil now has an interactive debugger!
Using the debugger
Just click the gutter next to your code to place a breakpoint:
When that line of code is about to run in the Anvil Editor, execution will pause and the debugger will open, showing you every variable in your code:
Going step-by-step
Use the buttons in the debugger to:
- Resume (Continue executing indefinitely, or until the next breakpoint)
- Step Over (Execute this line of code then pause again)
- Step Into (if this line of code is a function call, pause inside the function, otherwise works like Step Over)
- Step Out (execute to the end of the current function before pausing).
Tip: You can add and remove breakpoints while your code is paused! If you want to skip to the end of a block of code, place a new breakpoint at the end of that block and click Resume!
Debugging server code
Of course Anvil’s debugger works seamlessly across client and server code. Here’s a demo – watch me step from form code into server code, with access to the whole call stack:
What about background tasks and HTTP endpoints?
They work too! Just set a breakpoint at the appropriate point in your Server Modules, then launch that background task or hit that HTTP endpoint.
Note: The breakpoints you set only apply to your personal debug environment – that is, apps you run in the Editor or endpoints you call with a debug link. So if you want to use breakpoints to debug your HTTP endpoints, you’ll need to choose Get a link to my debug environment in the Publish dialog.
Availability
Everyone, including Free users, can use Anvil’s debugger on client-side (Form) code, but debugging server side code requires a Business Plan or higher.
Reporting issues
This is our first release of this new functionality, and naturally there will be corners that you folks will instantly battle-test in ways we never dreamed of 
If you’ve run into something that looks like a bug, or which you don’t know how to deal with, post in the Q&A forum as usual!
More coming soon
This is just the first version of the Anvil Debugger. We’ve got plans for lots more features - stay tuned!
