Follow this post to have Github Actions check URLs on Commit. It uses Github hosted runners with a node package that will check Markdown format and validity of external urls on your site.
Go to Azure-in-bullet-points repo
.github/workflows/quality-checks.ymlfiles to your site.
Try tweaking it if needed, but you should be able to do a push to Github and it will check URLs on your website.
I have since removed it on mine due to the high amount of posts and low amount of effort I want to put in to fix :)
- Original code is still retained here though if interested