diff --git a/openless-all/app/src-tauri/src/lib.rs b/openless-all/app/src-tauri/src/lib.rs
index e86153098..25bcd5352 100644
--- a/openless-all/app/src-tauri/src/lib.rs
+++ b/openless-all/app/src-tauri/src/lib.rs
@@ -132,7 +132,7 @@ use std::time::Duration;
 
 const LOG_ROTATE_LIMIT_BYTES: u64 = 10 * 1024 * 1024;
 #[cfg(target_os = "macos")]
-const OPENLESS_BUNDLE_ID: &str = "com.openless.app";
+const OPENLESS_BUNDLE_ID: &str = crate::persistence::BUNDLE_ID;
 
 /// Positions the QA window at the bottom-center of the screen on first show only, so the
 /// user-dragged position survives hide → show cycles. See issue #118 v2.
@@ -1902,14 +1902,14 @@ pub fn log_dir_path() -> std::path::PathBuf {
             return std::path::PathBuf::from(home)
                 .join("Library")
                 .join("Logs")
-                .join("OpenLess");
+                .join(crate::persistence::APP_DIR_NAME);
         }
     }
     #[cfg(target_os = "windows")]
     {
         if let Ok(local) = std::env::var("LOCALAPPDATA") {
             return std::path::PathBuf::from(local)
-                .join("OpenLess")
+                .join(crate::persistence::APP_DIR_NAME)
                 .join("Logs");
         }
     }
@@ -1919,7 +1919,7 @@ pub fn log_dir_path() -> std::path::PathBuf {
             return std::path::PathBuf::from(home)
                 .join(".local")
                 .join("share")
-                .join("OpenLess")
+                .join(crate::persistence::APP_DIR_NAME)
                 .join("logs");
         }
     }
@@ -1934,7 +1934,7 @@ pub fn log_dir_path() -> std::path::PathBuf {
     }
     #[cfg(not(target_os = "android"))]
     {
-        std::env::temp_dir().join("OpenLess")
+        std::env::temp_dir().join(crate::persistence::APP_DIR_NAME)
     }
 }
 
diff --git a/openless-all/app/src-tauri/src/persistence/credentials.rs b/openless-all/app/src-tauri/src/persistence/credentials.rs
index e123505ca..192c25e3d 100644
--- a/openless-all/app/src-tauri/src/persistence/credentials.rs
+++ b/openless-all/app/src-tauri/src/persistence/credentials.rs
@@ -3497,7 +3497,7 @@ pub struct CredentialsVault;
 
 impl CredentialsVault {
     /// System credential store service name; maps to the Keychain service on macOS.
-    pub const SERVICE_NAME: &'static str = "com.openless.app";
+    pub const SERVICE_NAME: &'static str = super::BUNDLE_ID;
 
     pub(crate) fn bind_sync_gate(
         gate: std::sync::Arc<openless_core::credentials::SyncWriteGate>,
diff --git a/openless-all/app/src-tauri/src/persistence/mod.rs b/openless-all/app/src-tauri/src/persistence/mod.rs
index c274ee018..36bd10e84 100644
--- a/openless-all/app/src-tauri/src/persistence/mod.rs
+++ b/openless-all/app/src-tauri/src/persistence/mod.rs
@@ -58,6 +58,23 @@ pub(crate) use android_storage::{android_log_dir, android_openless_log_candidate
 const HISTORY_CAP: usize = 200;
 const PREFERENCES_FILE: &str = "preferences.json";
 
+/// Bundle identifier; also the system credential store service name. A personal
+/// side-by-side build sets `OPENLESS_BUNDLE_ID` at compile time (matching its Tauri
+/// identifier) so its permissions and credentials never mix with the official app's.
+#[cfg_attr(target_os = "android", allow(dead_code))]
+pub(crate) const BUNDLE_ID: &str = match option_env!("OPENLESS_BUNDLE_ID") {
+    Some(id) => id,
+    None => "com.openless.app",
+};
+
+/// Per-user data and log directory name, overridden by `OPENLESS_APP_DIR_NAME` the
+/// same way.
+#[cfg_attr(target_os = "android", allow(dead_code))]
+pub(crate) const APP_DIR_NAME: &str = match option_env!("OPENLESS_APP_DIR_NAME") {
+    Some(name) => name,
+    None => "OpenLess",
+};
+
 pub(crate) fn data_dir() -> Result<PathBuf> {
     #[cfg(target_os = "macos")]
     {
@@ -65,27 +82,27 @@ pub(crate) fn data_dir() -> Result<PathBuf> {
         Ok(PathBuf::from(home)
             .join("Library")
             .join("Application Support")
-            .join("OpenLess"))
+            .join(APP_DIR_NAME))
     }
 
     #[cfg(target_os = "windows")]
     {
         let appdata = std::env::var("APPDATA").context("APPDATA not set")?;
-        Ok(PathBuf::from(appdata).join("OpenLess"))
+        Ok(PathBuf::from(appdata).join(APP_DIR_NAME))
     }
 
     #[cfg(all(unix, not(target_os = "macos"), not(target_os = "android")))]
     {
         if let Ok(xdg) = std::env::var("XDG_DATA_HOME") {
             if !xdg.is_empty() {
-                return Ok(PathBuf::from(xdg).join("OpenLess"));
+                return Ok(PathBuf::from(xdg).join(APP_DIR_NAME));
             }
         }
         let home = std::env::var("HOME").context("HOME not set")?;
         Ok(PathBuf::from(home)
             .join(".local")
             .join("share")
-            .join("OpenLess"))
+            .join(APP_DIR_NAME))
     }
 
     #[cfg(target_os = "android")]