diff --git a/.github/scripts/check-yaml.cjs b/.github/scripts/check-yaml.cjs
new file mode 100644
index 0000000..5d04d0c
--- /dev/null
+++ b/.github/scripts/check-yaml.cjs
@@ -0,0 +1,63 @@
+const fs = require("fs");
+const yaml = require("js-yaml");
+const glob = require("glob");
+
+const SNAKE_CASE_REGEX = /^[a-z][a-z0-9_]*$/;
+
+let hasError = false;
+const parsedFiles = [];
+
+function checkKeys(obj, file, path = "") {
+  if (typeof obj !== "object" || obj === null) return;
+
+  for (const key of Object.keys(obj)) {
+    const fullPath = path ? `${path}.${key}` : key;
+
+    if (!SNAKE_CASE_REGEX.test(key)) {
+      console.error(
+        `❌ ${file} → clé invalide "${fullPath}" (snake_case requis)`
+      );
+      hasError = true;
+    }
+
+    checkKeys(obj[key], file, fullPath);
+  }
+}
+
+const files = glob.sync("**/*.{yml,yaml}", {
+  ignore: ["node_modules/**"]
+});
+
+if (files.length === 0) {
+  console.log("ℹ️ Aucun fichier YAML trouvé");
+  process.exit(0);
+}
+
+for (const file of files) {
+  try {
+    const content = fs.readFileSync(file, "utf8");
+    const data = yaml.load(content);
+
+    checkKeys(data, file);
+
+    parsedFiles.push({
+      file,
+      data
+    });
+  } catch (err) {
+    console.error(`❌ Erreur YAML dans ${file}`);
+    console.error(err.message);
+    hasError = true;
+  }
+}
+
+if (hasError) {
+  console.error("\n⛔ Validation YAML échouée");
+  process.exit(1);
+}
+
+/**
+ * OUTPUT FINAL
+ * Tu peux le parser dans un autre step GitHub Actions
+ */
+console.log(JSON.stringify(parsedFiles, null, 2));
diff --git a/.github/workflows/yaml-lint.yml b/.github/workflows/yaml-lint.yml
new file mode 100644
index 0000000..0383a44
--- /dev/null
+++ b/.github/workflows/yaml-lint.yml
@@ -0,0 +1,31 @@
+name: YAML format & snake_case check
+
+on:
+  push:
+    paths:
+      - "**/*.yml"
+      - "**/*.yaml"
+  pull_request:
+    paths:
+      - "**/*.yml"
+      - "**/*.yaml"
+
+jobs:
+  yaml-check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm install js-yaml glob
+
+      - name: Validate YAML files and keys
+        run: node .github/scripts/check-yaml.cjs
+