diff --git a/render.yaml b/render.yaml
index 56e817e..d503e24 100644
--- a/render.yaml
+++ b/render.yaml
@@ -11,7 +11,12 @@ services:
         sync: false
       # Memory optimization for Render free tier (512MB RAM)
       - key: WEB_CONCURRENCY
-        value: "1" # Single worker to fit in 512MB
+        # 0 = Puma single mode (the master process serves HTTP directly,
+        # no forked workers). Any value ≥ 1 spawns that many worker
+        # processes on top of the master, each adding ~150MB. Combined
+        # with the four Solid Queue subprocesses below, anything above
+        # single mode OOMs on the 512MB free tier.
+        value: "0"
       - key: RAILS_MAX_THREADS
         value: "3" # Cap threads to reduce memory
       - key: MALLOC_ARENA_MAX