diff --git a/app.py b/app.py
index abd49e26b..cfd73e83f 100644
--- a/app.py
+++ b/app.py
@@ -47,6 +47,7 @@ from fastapi.responses import JSONResponse, FileResponse, HTMLResponse
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.staticfiles import StaticFiles
 from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.middleware.gzip import GZipMiddleware
 
 # Core imports
 from core.constants import (
@@ -104,6 +105,16 @@ app.add_middleware(
     ],
 )
 
+# ========= RESPONSE COMPRESSION (gzip) =========
+# The frontend's text assets (style.css, index.html, the JS bundles) shipped
+# uncompressed on every cold load. gzip cuts CSS/JS/HTML by ~75-85% on the wire
+# with no behavioural change. Starlette's GZipMiddleware excludes
+# `text/event-stream` by default, so the SSE streams (chat, shell, research,
+# model-probe — all served with media_type="text/event-stream") are never
+# compressed or buffered; only complete bodies over minimum_size are. The
+# security-header middleware composes cleanly on top.
+app.add_middleware(GZipMiddleware, minimum_size=1024, compresslevel=6)
+
 # ========= SECURITY HEADERS MIDDLEWARE =========
 app.add_middleware(SecurityHeadersMiddleware)