# Internal link discovery

Canonical HTML: /atlas/internal-links
Atlas version: atlas-2026-07-28-v1
Category: Discovery and crawl frontiers

## Definition

Ordinary HTML links are the most portable discovery mechanism because they are visible without executing JavaScript.

## How it works

A crawler parses anchor destinations, normalizes them, applies policy, and adds unseen URLs to its frontier. Anchor placement and graph connectivity affect how soon a page is encountered.

## How to validate it

Compare the raw response HTML with the rendered DOM and record the exact source page and discovery mechanism for every new URL.

## Common failure

Buttons, click handlers, and script-generated routes can look like navigation to a person while providing no crawlable URL in the server response.

## Related topics

- [URL normalization](/atlas/url-normalization)
- [Orphan pages](/atlas/orphan-pages)