# Query Monitor (headless / backend-only) Query Monitor is UI-first, but it can expose useful data to backend-only tooling. ## What it can show Query Monitor can help debug: - DB queries (slow/dupes/errors), hooks/actions, HTTP API calls, PHP errors Plugin page: - https://wordpress.org/plugins/query-monitor/ Configuration constants: - https://querymonitor.com/help/configuration-constants/ ## REST API requests (no browser needed) Query Monitor can add performance/error info to authenticated REST responses. Docs: - https://querymonitor.com/wordpress-debugging/rest-api-requests/ High-level approach: 1. Authenticate (nonce or Application Password). 2. Make a REST request and inspect response headers like `x-qm-overview-*`. 3. If you request an enveloped response (`?_envelope`), you can get a `qm` property with: - DB queries details, cache stats, HTTP API request details, etc. ## Guardrails - Query Monitor adds some overhead; don’t enable it in production without approval. - If it’s already installed by your platform (e.g. VIP), you may need to grant `view_query_monitor`.