A Visual Studio Code extension would be great

[xucian]

Yep. Currently using this, but I see actionlint is getting more frequent updates, and I like the online tool it provides. Can you build a VS Code extension out of it?

[rhysd]

I'd recommend to use both actionlint and the extension. I'm not using VS Code daily, but the extension seems to provide many useful functions like completion. On the other hand, checks by actionlint seem to be stricter. Though I'm not familiar with VS Code, running actionlint on saving file and checking the status would be sufficient (on non-zero status, show the command output).

I could make an extension, but I could not maintain it because I'd not be a user of the extension.