diff --git a/src/server/services/backupService.test.ts b/src/server/services/backupService.test.ts
index 4da9f00..71e068c 100644
--- a/src/server/services/backupService.test.ts
+++ b/src/server/services/backupService.test.ts
@@ -290,6 +290,52 @@ describe('backupService', () => {
     ]);
   });
 
+  it('does not export runtime database config in preferences backups', async () => {
+    await db.insert(schema.settings).values([
+      { key: 'db_type', value: JSON.stringify('postgres') },
+      { key: 'db_url', value: JSON.stringify('postgres://metapi:secret@db.example.com:5432/metapi') },
+      { key: 'db_ssl', value: JSON.stringify(true) },
+      { key: 'routing_fallback_unit_cost', value: JSON.stringify(0.25) },
+    ]).run();
+
+    const exported = await backupService.exportBackup('preferences') as any;
+    const exportedSettingKeys = exported.preferences.settings.map((row: { key: string }) => row.key);
+
+    expect(exportedSettingKeys).toContain('routing_fallback_unit_cost');
+    expect(exportedSettingKeys).not.toContain('db_type');
+    expect(exportedSettingKeys).not.toContain('db_url');
+    expect(exportedSettingKeys).not.toContain('db_ssl');
+  });
+
+  it('ignores imported runtime database config settings', async () => {
+    const result = await backupService.importBackup({
+      version: '2.1',
+      timestamp: Date.now(),
+      type: 'preferences',
+      preferences: {
+        settings: [
+          { key: 'db_type', value: 'postgres' },
+          { key: 'db_url', value: 'postgres://metapi:secret@db.example.com:5432/metapi' },
+          { key: 'db_ssl', value: true },
+          { key: 'routing_fallback_unit_cost', value: 0.25 },
+        ],
+      },
+    });
+
+    expect(result.sections.preferences).toBe(true);
+    expect(result.appliedSettings).toEqual([
+      { key: 'routing_fallback_unit_cost', value: 0.25 },
+    ]);
+
+    const settingsRows = await db.select().from(schema.settings).all();
+    const savedKeys = settingsRows.map((row) => row.key);
+
+    expect(savedKeys).toContain('routing_fallback_unit_cost');
+    expect(savedKeys).not.toContain('db_type');
+    expect(savedKeys).not.toContain('db_url');
+    expect(savedKeys).not.toContain('db_ssl');
+  });
+
   it('preserves local logs and runtime stats when importing account backups', async () => {
     const exportedAt = '2026-03-20T09:00:00.000Z';
     const localRuntimeAt = '2026-03-21T10:30:00.000Z';
diff --git a/src/server/services/backupService.ts b/src/server/services/backupService.ts
index 3badddc..1df030d 100644
--- a/src/server/services/backupService.ts
+++ b/src/server/services/backupService.ts
@@ -228,6 +228,10 @@ interface BackupImportResult {
 const EXCLUDED_SETTING_KEYS = new Set<string>([
   // Keep current admin login credential unchanged to avoid accidental lock-out.
   'auth_token',
+  // Runtime database selection is environment-bound and must not be propagated by backups.
+  'db_type',
+  'db_url',
+  'db_ssl',
 ]);
 const BACKUP_WEBDAV_CONFIG_SETTING_KEY = 'backup_webdav_config_v1';
 const BACKUP_WEBDAV_STATE_SETTING_KEY = 'backup_webdav_state_v1';
diff --git a/src/server/services/databaseMigrationService.test.ts b/src/server/services/databaseMigrationService.test.ts
index 223ad59..54a11ee 100644
--- a/src/server/services/databaseMigrationService.test.ts
+++ b/src/server/services/databaseMigrationService.test.ts
@@ -465,4 +465,46 @@ describe('databaseMigrationService', () => {
       vi.resetModules();
     }
   });
+
+  it('excludes runtime database config settings from migration statements', () => {
+    const statements = __databaseMigrationServiceTestUtils.buildStatements({
+      version: 'test',
+      timestamp: Date.now(),
+      accounts: {
+        sites: [],
+        siteAnnouncements: [],
+        siteDisabledModels: [],
+        accounts: [],
+        accountTokens: [],
+        checkinLogs: [],
+        modelAvailability: [],
+        tokenModelAvailability: [],
+        tokenRoutes: [],
+        routeChannels: [],
+        routeGroupSources: [],
+        proxyLogs: [],
+        proxyVideoTasks: [],
+        proxyFiles: [],
+        downstreamApiKeys: [],
+        events: [],
+      },
+      preferences: {
+        settings: [
+          { key: 'db_type', value: 'sqlite' },
+          { key: 'db_url', value: '/app/data/hub.db' },
+          { key: 'db_ssl', value: false },
+          { key: 'routing_fallback_unit_cost', value: 0.25 },
+        ],
+      },
+    } as any);
+
+    const migratedSettingKeys = statements
+      .filter((statement) => statement.table === 'settings')
+      .map((statement) => statement.values[0]);
+
+    expect(migratedSettingKeys).toContain('routing_fallback_unit_cost');
+    expect(migratedSettingKeys).not.toContain('db_type');
+    expect(migratedSettingKeys).not.toContain('db_url');
+    expect(migratedSettingKeys).not.toContain('db_ssl');
+  });
 });
diff --git a/src/server/services/databaseMigrationService.ts b/src/server/services/databaseMigrationService.ts
index d03f0b9..82e8a35 100644
--- a/src/server/services/databaseMigrationService.ts
+++ b/src/server/services/databaseMigrationService.ts
@@ -85,6 +85,7 @@ interface InsertStatement {
 }
 
 const DIALECTS: MigrationDialect[] = ['sqlite', 'mysql', 'postgres'];
+const RUNTIME_DATABASE_SETTING_KEYS = new Set(['db_type', 'db_url', 'db_ssl']);
 
 function asString(value: unknown): string {
   return typeof value === 'string' ? value.trim() : '';
@@ -628,6 +629,9 @@ function buildStatements(snapshot: BackupSnapshot): InsertStatement[] {
   }
 
   for (const row of snapshot.preferences.settings) {
+    if (RUNTIME_DATABASE_SETTING_KEYS.has(row.key)) {
+      continue;
+    }
     statements.push({
       table: 'settings',
       columns: ['key', 'value'],