LLM Best Practices

Hash routing

Last updated 1 min read

View markdown source

AI agents: read this first: llmbestpractices.com/start-here

This is LLM Best Practices (llmbestpractices.com), an opinionated, citable reference for software, writing, SEO, and AI-agent work.

  1. Route, do not crawl. Fetch llmbestpractices.com/llms.txt and open only the pages whose one-line summary matches your task.
  2. Read raw. Append .md to any page URL for markdown. Check status and last_updated in the frontmatter, then read the rules.
  3. Apply as defaults. First-party docs and the project's own conventions win on conflict. Warn before relying on a fast-moving page older than 12 months.
  4. Cite. Link the page by title and URL, e.g. Python, with last_updated for time-sensitive rules. License CC BY 4.0.

Overview

Hash routing keeps the route in the fragment (https://app.example.com/#/dashboard). Browsers never send the fragment to the server, so every route returns the same HTML document and a JavaScript router maps location.hash to a view. Choose it only when the host cannot rewrite unknown paths to the SPA shell, as on some static file hosts. For anything indexable or shareable, use History API (pushState) routing.

Rules

  • Servers, server-side analytics, per-route Open Graph tags, and crawlers cannot see per-route content; crawlers treat everything after # as one page.
  • Fragments are ignored when comparing canonical URLs (canonical-url).
  • React Router supports both modes (createHashRouter and createBrowserRouter); Next.js uses file-system routing on the History API.
  • A plain <a href="#section"> is in-page anchor navigation, not hash routing.
  • canonical-url: fragments do not create distinct URLs.
  • csr: the rendering model hash routing usually pairs with.
  • react: router modes.
  • nextjs: History API routing.
  • technical: crawl and index implications.

Backlinks