[recursive]

In the 90s, we used Server Side Includes (SSI) for this. Probably still works.

[skyfaller]

One modern approach would be Caddy Server's templates, using Golang templating:

https://caddyserver.com/docs/modules/http.handlers.templates

The "include" function should do the job:

{{include "path/to/file.html"}}

[ZYbCRq22HbJ2y7]

httpd, nginx, a number of other servers support SSI

https://nginx.org/en/docs/http/ngx_http_ssi_module.html

Caddy chose not to, I guess?

https://caddy.community/t/caddy-update-on-ssi-server-side-in...

[alwillis]

You generally can’t use SSI on many popular platforms for static websites like Netlify, etc.

[someothherguyy]

However, you could generate the static HTML easily and then publish it on those platforms, which is what many people do today (probably not often using SSI).