The Open Food Facts Folksonomy Engine API lets developers add and manage free-form property/value tags (folksonomy) on products in the Open Food Facts database. Authenticate with username/password or an Open Food Facts session cookie to receive a bearer token for subsequent requests.

Main capabilities:

• Tag management: create, update and delete product tags with version tracking.
• Discovery: list product tags, fetch tag versions, browse keys and retrieve unique values with counts and filters.
• Product statistics: query products by tags and retrieve tag statistics.
• Admin operations: check property rename clashes, perform bulk renames, replace or delete values across all products.
• Authentication and user info endpoints, plus a ping/health endpoint.

Use cases include crowd-sourced tagging workflows, data cleanup and normalization, analytics on product attributes, and integrating rich product metadata into apps and services. See the project page for implementation details: Folksonomy Engine.