How Updating a Tag Actually Works in WordPress
WordPress's REST API updates a tag via POST to /wp-json/wp/v2/tags/{id}, sending only the fields (name, slug, description) that need to change.
Real API Details
Changing a tag's slug changes the URL of its archive page immediately -- WordPress doesn't automatically create a redirect from the old slug-based URL to the new one, unlike some redirect behavior for post permalink changes.
Practical Considerations
Set up a manual redirect (or use a redirect plugin) after changing a tag's slug if the old tag archive URL was indexed or linked externally, since WordPress won't handle that redirect automatically.
Use cases
Representative use cases:
- Correct tag metadata after data enrichment.
- Align tag semantics with external catalogs during migrations.
- Bulk tag updates during site rebranding.
- Automate taxonomy cleanup based on external signals.