diff --git a/GUIDE_API_KEY.md b/GUIDE_API_KEY.md
index 5a9b65e..688b6c1 100644
--- a/GUIDE_API_KEY.md
+++ b/GUIDE_API_KEY.md
@@ -45,16 +45,3 @@ To configure multiple keys with per-key rate limits:
 ```
 
 The app will round-robin requests across configured keys and respect `rateLimitPerMinute` values.
-
-## Storing keys safely
-
-- Do not commit `config.json` with keys to version control. Add `config.json` to `.gitignore`.
-- Alternatively, keep a `config.json.example` in the repo and place the real keys in a local `config.json`.
-- If you prefer to use environment variables, you can have a small loader script that reads an env var and writes `config.json` before running the app.
-
-## Troubleshooting
-
-- If you get quota or 403 errors, check API restrictions, project quotas, and whether the key is restricted to the wrong IP/referrer.
-- Use multiple keys to spread requests if you hit per-key quotas.
-
-*** End of guide ***
diff --git a/GUIDE_SERVICE_ACCOUNT.md b/GUIDE_SERVICE_ACCOUNT.md
index 41a9be0..4a7f0b9 100644
--- a/GUIDE_SERVICE_ACCOUNT.md
+++ b/GUIDE_SERVICE_ACCOUNT.md
@@ -37,14 +37,20 @@ This guide explains how to create a Google service account, enable the Sheets AP
 
 ## 5. Configure the project
 
-In `config.json`, set the `credentialsPath` field to the JSON file path, and remove any `apiKey` or `apiKeys` entries if you are using service account auth.
-
-Example:
+In `config.json`, add the service account credentials under the `serviceAccounts` array. Here's an example using service account authentication:
 
 ```json
 {
-  "credentialsPath": "credentials.json",
-  "rateLimitPerMinute": 50,
+  "serviceAccounts": [
+    {
+      "path": "credentials.json",
+      "rateLimitPerMinute": 50
+    },
+    {
+      "path": "credentials.json",
+      "rateLimitPerMinute": 50
+    }
+  ],
   "documents": [
     {
       "documentId": "YOUR_SPREADSHEET_ID",
@@ -58,4 +64,6 @@ Example:
     }
   ]
 }
-```
\ No newline at end of file
+```
+
+The app will round-robin requests across configured accounts and respect `rateLimitPerMinute` values.
\ No newline at end of file
diff --git a/config.example.json b/config.example.json
index 6015870..06ec215 100644
--- a/config.example.json
+++ b/config.example.json
@@ -13,6 +13,10 @@
     {
       "path": "credentials.json",
       "rateLimitPerMinute": 50
+    },
+    {
+      "path": "credentials_2.json",
+      "rateLimitPerMinute": 50
     }
   ],
   "documents": [
@@ -25,6 +29,16 @@
           "outputFilename": "sheet1.csv"
         }
       ]
+    },
+    {
+      "documentId": "YOUR_SPREADSHEET_ID_2",
+      "outputDir": "output/your-document-2",
+      "sheets": [
+        {
+          "name": "Sheet1",
+          "outputFilename": "sheet1.csv"
+        }
+      ]
     }
   ]
 }