Development Notes

You're getting a localhost certificate expiration error

When you're developing an Office add-in, you will need to test and run your code on your local machine. To do this, you will need to run the development server on your local machine, which will host the files for the add-in.

The localhost certificate will expire every 30 days, after which you will need to reinstall a new certificate.

Use the following command to install a new certificate:

npx office-addin-dev-certs install --machine

If you need to uninstall the certificate for any reason:

npx office-addin-dev-certs uninstall --machine

If you are having issue with your certificate, you can use this to help troubleshoot:

npx office-addin-dev-certs verify