diff --git a/apps/base/arrstack/prowlarr/deployment.yaml b/apps/base/arrstack/prowlarr/deployment.yaml
index a6a95cc..4e79607 100644
--- a/apps/base/arrstack/prowlarr/deployment.yaml
+++ b/apps/base/arrstack/prowlarr/deployment.yaml
@@ -21,10 +21,12 @@ spec:
         fsGroup: 1000
         fsGroupChangePolicy: OnRootMismatch
       initContainers:
-        # Enforce the Vault-sourced API key in /config/config.xml before the app
-        # starts. Vault is source of truth (override bootstrap): the key is minted
-        # in Vault, synced by VSO into the prowlarr-apikey Secret, and written here.
-        # Runs as root to fix ownership; touches only the <ApiKey> element.
+        # Enforce the Vault-sourced API key and the reverse-proxy URL base in
+        # /config/config.xml before the app starts. Vault is source of truth
+        # (override bootstrap): the key is minted in Vault, synced by VSO into the
+        # prowlarr-apikey Secret, and written here. UrlBase=/prowlarr lets arrproxy
+        # forward arrstack.unkin.net/prowlarr/... with the prefix preserved (no 307).
+        # Runs as root to fix ownership; touches only <ApiKey> and <UrlBase>.
         - name: apikey-init
           image: artifactapi.k8s.syd1.au.unkin.net/dockerhub/library/busybox:1.37.0
           imagePullPolicy: IfNotPresent
@@ -43,21 +45,29 @@ spec:
               set -eu
               case "$API_KEY" in
                 "" | *[!0-9a-fA-F]*)
-                  echo "apikey-init: API_KEY missing or not hex; refusing" >&2
+                  echo "config-init: API_KEY missing or not hex; refusing" >&2
                   exit 1
                   ;;
               esac
+              URL_BASE=/prowlarr
               CFG=/config/config.xml
               if [ ! -f "$CFG" ]; then
-                printf '<Config>\n  <ApiKey>%s</ApiKey>\n</Config>\n' "$API_KEY" > "$CFG"
-              elif grep -q '<ApiKey>' "$CFG"; then
-                sed -i "s|<ApiKey>[^<]*</ApiKey>|<ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                printf '<Config>\n  <ApiKey>%s</ApiKey>\n  <UrlBase>%s</UrlBase>\n</Config>\n' "$API_KEY" "$URL_BASE" > "$CFG"
               else
-                sed -i "s|<Config>|<Config>\n  <ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                if grep -q '<ApiKey>' "$CFG"; then
+                  sed -i "s|<ApiKey>[^<]*</ApiKey>|<ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                else
+                  sed -i "s|<Config>|<Config>\n  <ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                fi
+                if grep -q '<UrlBase>' "$CFG"; then
+                  sed -i "s|<UrlBase>[^<]*</UrlBase>|<UrlBase>${URL_BASE}</UrlBase>|" "$CFG"
+                else
+                  sed -i "s|<Config>|<Config>\n  <UrlBase>${URL_BASE}</UrlBase>|" "$CFG"
+                fi
               fi
               chown 1000:1000 "$CFG"
               chmod 600 "$CFG"
-              echo "apikey-init: <ApiKey> enforced from Vault"
+              echo "config-init: <ApiKey> and <UrlBase>=${URL_BASE} enforced from Vault"
           resources:
             requests:
               cpu: 50m
@@ -85,7 +95,7 @@ spec:
               value: Australia/Sydney
           livenessProbe:
             httpGet:
-              path: /ping
+              path: /prowlarr/ping
               port: http
             initialDelaySeconds: 30
             periodSeconds: 30
@@ -93,7 +103,7 @@ spec:
             failureThreshold: 3
           readinessProbe:
             httpGet:
-              path: /ping
+              path: /prowlarr/ping
               port: http
             initialDelaySeconds: 10
             periodSeconds: 10
diff --git a/apps/base/arrstack/radarr/deployment.yaml b/apps/base/arrstack/radarr/deployment.yaml
index 6ed1f9d..7a09cf1 100644
--- a/apps/base/arrstack/radarr/deployment.yaml
+++ b/apps/base/arrstack/radarr/deployment.yaml
@@ -21,10 +21,12 @@ spec:
         fsGroup: 1000
         fsGroupChangePolicy: OnRootMismatch
       initContainers:
-        # Enforce the Vault-sourced API key in /config/config.xml before the app
-        # starts. Vault is source of truth (override bootstrap): the key is minted
-        # in Vault, synced by VSO into the radarr-apikey Secret, and written here.
-        # Runs as root to fix ownership; touches only the <ApiKey> element.
+        # Enforce the Vault-sourced API key and the reverse-proxy URL base in
+        # /config/config.xml before the app starts. Vault is source of truth
+        # (override bootstrap): the key is minted in Vault, synced by VSO into the
+        # radarr-apikey Secret, and written here. UrlBase=/radarr lets arrproxy
+        # forward arrstack.unkin.net/radarr/... with the prefix preserved (no 307).
+        # Runs as root to fix ownership; touches only <ApiKey> and <UrlBase>.
         - name: apikey-init
           image: artifactapi.k8s.syd1.au.unkin.net/dockerhub/library/busybox:1.37.0
           imagePullPolicy: IfNotPresent
@@ -43,21 +45,29 @@ spec:
               set -eu
               case "$API_KEY" in
                 "" | *[!0-9a-fA-F]*)
-                  echo "apikey-init: API_KEY missing or not hex; refusing" >&2
+                  echo "config-init: API_KEY missing or not hex; refusing" >&2
                   exit 1
                   ;;
               esac
+              URL_BASE=/radarr
               CFG=/config/config.xml
               if [ ! -f "$CFG" ]; then
-                printf '<Config>\n  <ApiKey>%s</ApiKey>\n</Config>\n' "$API_KEY" > "$CFG"
-              elif grep -q '<ApiKey>' "$CFG"; then
-                sed -i "s|<ApiKey>[^<]*</ApiKey>|<ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                printf '<Config>\n  <ApiKey>%s</ApiKey>\n  <UrlBase>%s</UrlBase>\n</Config>\n' "$API_KEY" "$URL_BASE" > "$CFG"
               else
-                sed -i "s|<Config>|<Config>\n  <ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                if grep -q '<ApiKey>' "$CFG"; then
+                  sed -i "s|<ApiKey>[^<]*</ApiKey>|<ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                else
+                  sed -i "s|<Config>|<Config>\n  <ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                fi
+                if grep -q '<UrlBase>' "$CFG"; then
+                  sed -i "s|<UrlBase>[^<]*</UrlBase>|<UrlBase>${URL_BASE}</UrlBase>|" "$CFG"
+                else
+                  sed -i "s|<Config>|<Config>\n  <UrlBase>${URL_BASE}</UrlBase>|" "$CFG"
+                fi
               fi
               chown 1000:1000 "$CFG"
               chmod 600 "$CFG"
-              echo "apikey-init: <ApiKey> enforced from Vault"
+              echo "config-init: <ApiKey> and <UrlBase>=${URL_BASE} enforced from Vault"
           resources:
             requests:
               cpu: 50m
@@ -85,7 +95,7 @@ spec:
               value: Australia/Sydney
           livenessProbe:
             httpGet:
-              path: /ping
+              path: /radarr/ping
               port: http
             initialDelaySeconds: 30
             periodSeconds: 30
@@ -93,7 +103,7 @@ spec:
             failureThreshold: 3
           readinessProbe:
             httpGet:
-              path: /ping
+              path: /radarr/ping
               port: http
             initialDelaySeconds: 10
             periodSeconds: 10
diff --git a/apps/base/arrstack/sonarr/deployment.yaml b/apps/base/arrstack/sonarr/deployment.yaml
index 6e9be13..230208a 100644
--- a/apps/base/arrstack/sonarr/deployment.yaml
+++ b/apps/base/arrstack/sonarr/deployment.yaml
@@ -24,10 +24,12 @@ spec:
         fsGroup: 1000
         fsGroupChangePolicy: OnRootMismatch
       initContainers:
-        # Enforce the Vault-sourced API key in /config/config.xml before the app
-        # starts. Vault is source of truth (override bootstrap): the key is minted
-        # in Vault, synced by VSO into the sonarr-apikey Secret, and written here.
-        # Runs as root to fix ownership; touches only the <ApiKey> element.
+        # Enforce the Vault-sourced API key and the reverse-proxy URL base in
+        # /config/config.xml before the app starts. Vault is source of truth
+        # (override bootstrap): the key is minted in Vault, synced by VSO into the
+        # sonarr-apikey Secret, and written here. UrlBase=/sonarr lets arrproxy
+        # forward arrstack.unkin.net/sonarr/... with the prefix preserved (no 307).
+        # Runs as root to fix ownership; touches only <ApiKey> and <UrlBase>.
         - name: apikey-init
           image: artifactapi.k8s.syd1.au.unkin.net/dockerhub/library/busybox:1.37.0
           imagePullPolicy: IfNotPresent
@@ -46,21 +48,29 @@ spec:
               set -eu
               case "$API_KEY" in
                 "" | *[!0-9a-fA-F]*)
-                  echo "apikey-init: API_KEY missing or not hex; refusing" >&2
+                  echo "config-init: API_KEY missing or not hex; refusing" >&2
                   exit 1
                   ;;
               esac
+              URL_BASE=/sonarr
               CFG=/config/config.xml
               if [ ! -f "$CFG" ]; then
-                printf '<Config>\n  <ApiKey>%s</ApiKey>\n</Config>\n' "$API_KEY" > "$CFG"
-              elif grep -q '<ApiKey>' "$CFG"; then
-                sed -i "s|<ApiKey>[^<]*</ApiKey>|<ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                printf '<Config>\n  <ApiKey>%s</ApiKey>\n  <UrlBase>%s</UrlBase>\n</Config>\n' "$API_KEY" "$URL_BASE" > "$CFG"
               else
-                sed -i "s|<Config>|<Config>\n  <ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                if grep -q '<ApiKey>' "$CFG"; then
+                  sed -i "s|<ApiKey>[^<]*</ApiKey>|<ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                else
+                  sed -i "s|<Config>|<Config>\n  <ApiKey>${API_KEY}</ApiKey>|" "$CFG"
+                fi
+                if grep -q '<UrlBase>' "$CFG"; then
+                  sed -i "s|<UrlBase>[^<]*</UrlBase>|<UrlBase>${URL_BASE}</UrlBase>|" "$CFG"
+                else
+                  sed -i "s|<Config>|<Config>\n  <UrlBase>${URL_BASE}</UrlBase>|" "$CFG"
+                fi
               fi
               chown 1000:1000 "$CFG"
               chmod 600 "$CFG"
-              echo "apikey-init: <ApiKey> enforced from Vault"
+              echo "config-init: <ApiKey> and <UrlBase>=${URL_BASE} enforced from Vault"
           resources:
             requests:
               cpu: 50m
@@ -88,7 +98,7 @@ spec:
               value: Australia/Sydney
           livenessProbe:
             httpGet:
-              path: /ping
+              path: /sonarr/ping
               port: http
             initialDelaySeconds: 30
             periodSeconds: 30
@@ -96,7 +106,7 @@ spec:
             failureThreshold: 3
           readinessProbe:
             httpGet:
-              path: /ping
+              path: /sonarr/ping
               port: http
             initialDelaySeconds: 10
             periodSeconds: 10