diff --git a/chapitre-16/rules/flask.yaml b/chapitre-16/rules/flask.yaml
new file mode 100644
index 0000000..421d118
--- /dev/null
+++ b/chapitre-16/rules/flask.yaml
@@ -0,0 +1,17 @@
+groups:
+- name: FlaskErrors
+  rules:
+  - alert: HTTPError
+    expr: >
+      sum(
+        rate(
+          flask_http_request_duration_seconds_count{
+            status=~"[45].."
+          }[5m]
+        )
+      ) > 0
+    for: 5m
+    labels:
+      severity: critical
+    annotations:
+      summary: Too much 4xx or 5xx errors on Flask apps
diff --git a/chapitre-16/rules/spring-boot.yaml b/chapitre-16/rules/spring-boot.yaml
new file mode 100644
index 0000000..00e8740
--- /dev/null
+++ b/chapitre-16/rules/spring-boot.yaml
@@ -0,0 +1,22 @@
+groups:
+- name: SpringBootAlerts
+  rules:
+  - alert: HTTPError
+    expr: >
+      sum(
+        rate(
+          http_server_requests_seconds_count{status=~"[45].."}[5m]
+        )
+      ) > 0
+    for: 5m
+    labels:
+      severity: critical
+    annotations:
+      summary: Too much 4xx or 5xx errors on Spring boot apps
+  - alert: LogError
+    expr: sum(rate(logback_events_total{level="error"}[5m])) > 0
+    for: 5m
+    labels:
+      severity: critical
+    annotations:
+      summary: Too much log error activity since 5 minutes
diff --git a/chapitre-16/spring-boot/tomcat.yml b/chapitre-16/tomcat.yml
similarity index 100%
rename from chapitre-16/spring-boot/tomcat.yml
rename to chapitre-16/tomcat.yml