Content Accessibility · Emerging · Medium impact

Per-page content separation (no SPA fallback)

A catch-all route returning the same skeleton for every URL makes pages indistinguishable to an agent.

Emerging
Medium impact
Experimental standard

Per-page content separation (no SPA fallback) — Property, Value
Property	Value
Check id	`spa-fallback`
Dimension	Content Accessibility (22%)
Tier	Emerging — pool 5 pts
Weight inside tier	2
Impact	Medium
Maturity	Experimental — An early convention that may still change shape.
Conditional	No
Publishing skill	`server-rendering`
Standards	—

What is measured

This check declares no probe path; the scanner compares the homepage / with a second same-origin URL. Pass when the two responses have different <title> values and different main text (each route ships its own document); partial when the titles differ but the main content region is identical, or when an unknown path answers 200 with the app shell instead of 404; fail when two different URLs return the same title and near-identical markup — the catch-all rewrite to one index.html.

Reproduce it yourself

You do not have to take our word for any of this. Run the same measurement against your own domain:

              DOMAIN="https://example.com"
for p in / /about; do printf '%s\t' "$p"; curl -sL -o /tmp/page.html -w '%{http_code}\t' "$DOMAIN$p"; perl -0777 -ne 'm{<title[^>]*>(.*?)</title>}si and do { my $t=$1; $t=~s/\s+/ /g; print "title=$t\t" }; s{<(script|style)[^>]*>.*?</\1>}{}gsi; m{<main[^>]*>(.*?)</main>}si and $_=$1; s/<[^>]*>//g; s/\s+/ /g; print "text=", length($_), "\n"' /tmp/page.html; done

The fix

This is the artifact to ship. It is the complete change, not a description of one.

              // Serve dist/<route>/index.html per URL; never rewrite every path to one shell.
import express from 'express';
import { existsSync } from 'node:fs';

const app = express();

app.use((req, res) => {
  if (req.method !== 'GET') return res.status(405).end();
  const file = new URL(`dist${req.path.replace(/\/$/, '/index')}.html`, import.meta.url).pathname;
  if (existsSync(file)) return res.sendFile(file);
  res.status(404).type('html')
    .send('<!doctype html><html lang="en"><title>404</title><h1>Not found</h1></html>');
});

app.listen(3000);

Related checks

Related checks — Check, Tier, Impact, Same skill
Check	Tier	Impact	Same skill
`markdown-negotiation` — Markdown content negotiation	Recommended	Critical	—
`headings` — Semantic heading structure	Essential	High	—
`meta` — Title and summary metadata	Essential	High	—
`jsonld` — JSON-LD structured data	Essential	Critical	—
`faq-schema` — FAQ / question-answer schema	Recommended	High	—
`breadcrumb` — Breadcrumb / navigation schema	Emerging	Low	—
`summary` — Prominent summary block	Recommended	Medium	—
`lang` — Language declaration and multilingual access	Recommended	Medium	—