Client-Side Rendering

Client-side rendering is a way of building a website where the page that arrives is nearly empty, and the words appear only after code runs inside the visitor's browser. The client is the browser; the rendering — the assembling of the actual page — happens there rather than on the server before it is sent. Many modern site builders and app frameworks work this way by default, and for a human visitor the result is often excellent.

The trouble is that not every visitor runs the code. A browser does it without complaint. Machines reading the web at enormous scale frequently do not: running code for every page costs far more than simply requesting it, so many crawlers take whatever arrives in the first response and move on. When that first response is an empty shell, the empty shell is what they record.

This is the hardest fault on any website to notice, because every ordinary way of checking hides it. You look at your own site in your own browser and it is fine. Your customers say it is fine. It is fine. The failure exists only in a view you never see, which is why it can sit undiscovered for the entire life of a site.

The fix is generally not a rebuild. Most frameworks that render on the client can also render on the server, or build their pages in advance, and switching that on is usually a setting rather than a project. This is one of the few problems in this territory that genuinely tends to need a developer — an hour of one, told precisely what to change.

The human translation is a shop whose window display is only assembled once somebody walks in. Customers see it and think nothing of it. The surveyor who drives past to record what is on the street sees an empty window, writes down empty, and does not come back.