You want to look at a static site you have on hand. The reflex, for anyone who has ever developed, is immediate: python -m http.server, or npx serve, then open the browser. On a computer it takes ten seconds.
On an iPhone or an iPad that reflex has nothing to stand on. And the real question becomes: did you actually need a server?
Because opening a file directly over file:// causes real problems in a desktop browser. Requests to other files are blocked by the origin policy, JavaScript modules refuse to load, and some APIs are only available in a secure context.
So the local server is not there to serve the files, which are already there. It is there to give the page an origin.
It is, the moment you do anything other than read:
In all of those, start a server, and do it from a development machine. No reading app replaces that, and this article does not claim otherwise.
If your goal is to read, the list is shorter than people think. Consulting an exported documentation set, rereading a generated report, browsing an archived site, checking a client deliverable before passing it on: none of that requires an HTTP origin.
What you need is an app that resolves relative paths correctly and runs the page's CSS and JavaScript. That is exactly what Pagira does, on iPhone and iPad, with nothing to start and nothing to publish.
Styles and interactive pages are supported, see CSS and JavaScript in local pages.
There is a difference in kind between reading a file on your device and uploading it to an online service to look at it. A client deliverable, an unannounced mockup, internal documentation: these are contents you are not always entitled to decide the distribution of. Staying local removes the question.
Exports from Hugo, Jekyll, MkDocs, Docusaurus or a converted notebook are self-contained static folders. They read as they are, with no build and no server. The subject is covered in detail in reading technical documentation offline on iPad.
Interactive pages behave as expected. That said, if your page depends on an API restricted to secure contexts or on a service worker, you need a real server: that is a limit of the model, not a setting to find.
Some apps offer it. For plain reading, that adds a layer whose only job is to work around a problem you do not have.
It will need a connection, as it would in a browser. What is local is the site, not the services it queries.
With Open with Pagira from Files. See open from anywhere.
Yes, that is the starting point: the files are on the device. For a folder in iCloud, download an offline copy before you leave.