# Categories and tags

## Categories

A category is a curated, hierarchical container. A question or topic belongs to exactly one category.

Each category carries:

| Field | Purpose |
|---|---|
| Name, slug | Display and URL (`/c/{slug}`) |
| Parent | Optional single level of nesting |
| Description | Shown on the category page |
| SEO title, SEO description | Override the generated metadata |
| Index policy | `inherit`, `index`, or `noindex` |
| Canonical URL | Optional same-site canonical override |
| Locale | In multilingual mode, which language the category belongs to |

**Sitemap rule:** a category is included when it is not `noindex` **and** it has at least one published question **or** at least one published topic. A topic-only category is a real page and belongs in the sitemap; an empty one does not.

## Tags

A tag is a flat, member-facing label. A question may carry several.

Each tag carries name, slug (`/t/{slug}`), description, SEO fields, index policy, canonical override, and locale.

### Merging

**Content → Tags → Merge** folds one tag into another: every question tagged with the source is retagged to the target, and the source is removed. Use this instead of deleting a tag that has content behind it.

### Synonyms

A tag can declare synonyms. Searching or tagging with a synonym resolves to the canonical tag, so `js`, `javascript` and `java-script` do not fragment the same topic across three pages.

## Locale scoping

In multilingual mode, taxonomy is locale-scoped. Before disabling a language, reassign or re-enable any categories and tags that use it — the admin warns you when content would be stranded.

## Following

When follows are enabled, members can follow categories and tags to see matching content in their feed.

## SEO guidance

- Do not create a category you cannot fill. An empty taxonomy page is a thin page.
- Prefer merging tags over accumulating near-duplicates.
- Set `noindex` on any taxonomy page that exists purely for internal navigation.

See [SEO](../03-configuration/SEO.md).
