I achieve this using https://brid.gy/ (or https://fed.brid.gy/ if you want your blog to appear as a first class member of the Fediverse), though in my case I just syndicate out to Twitter. I then collect the webmentions using https://webmention.io/.
The nice thing about this is I get a breadth of methods for receiving comments/reactions across multiple platforms, including anything that directly supports webmention (such as https://micro.blog/, where my posts are also syndicated), without having to do any of the platform-specific wiring myself.
That's what webmention.io is for. It'll receive webmentions on your behalf and then expose an API to pull em down. You hit that API during your static site build or do it dynamically with some client side JS. Either way it allows you to avoid hosting any services yourself.
Honestly, I set up webmentions to use brid.gy, not just for the sake of using webmentions. I wanted a two-way integration between my static blog and Twitter, and this solution has done the job nicely.
That I ended up with direct webmention support was just a bonus as far as I'm concerned.
Correct. Using the right microformats, it'll auto syndicate notes as tweets and full posts as tweets with a summary and a link. All my site has to do is shoot out a webmention to brid.gy and it does the rest.
Then when people react (reply, like, etc) it'll proxy those interactions back as webmentions.
For the unaware, they're essentially identical to WordPress' Pingbacks. You configure your website so that other websites let you know whenever they link to you.
The nice thing about this is I get a breadth of methods for receiving comments/reactions across multiple platforms, including anything that directly supports webmention (such as https://micro.blog/, where my posts are also syndicated), without having to do any of the platform-specific wiring myself.