diff --git a/docs/DEPLOYMENT.md b/docs/DEPLOYMENT.md
index 2d920a73..c5a649ba 100644
--- a/docs/DEPLOYMENT.md
+++ b/docs/DEPLOYMENT.md
@@ -149,6 +149,7 @@ All vars are set in `.env` at the repo root (copy from `.env.example`). The back
 | `PORT_GLITCHTIP` | Host port for the GlitchTip UI (bound to `127.0.0.1` only) | `3002` | — | — |
 | `GLITCHTIP_DOMAIN` | Public-facing base URL for GlitchTip (used in email links and CORS) | `http://localhost:3002` | YES (prod) | — |
 | `GLITCHTIP_SECRET_KEY` | Django secret key for GlitchTip — generate with `python3 -c "import secrets; print(secrets.token_hex(32))"` | — | YES | YES |
+| `VITE_SENTRY_DSN` | GlitchTip/Sentry DSN for the frontend (SvelteKit) — injected at build time via Vite. Leave empty to disable. Set after GlitchTip first-run (§4). | — | — | YES |
 
 ---