The 6-step URL pattern playbook

The 6-step URL pattern playbook
Design the pattern once, before a single page generates. Changing it later means a redirect migration.

— Step 1 (SEO): Pick one canonical shape per template. Example: /best/{category}/in/{city}. One template, one shape, no exceptions.
— Step 2 (Dev): Lowercase, hyphenate, ASCII-fold. Gate: regex ^[a-z0-9-]+$ passes on every slug segment.
— Step 3 (Dev): Resolve slug collisions deterministically. Two entities with the same slug → append a stable ID, never a random one.
— Step 4 (SEO): Cap depth at 3 path segments. Gate: deeper than 3 → flatten or fail.
— Step 5 (Dev): Make slugs immutable. Gate: entity rename must NOT change the URL; store slug at creation.
— Step 6 (SEO): Reserve a 301 map column now, even empty. Future renames write here.

Guardrail: no query parameters in indexable URLs. Filters live behind noindex or canonical.

Ship gate: don't publish until all boxes are checked.