diff --git a/arduino-ide-extension/src/common/protocol/sketches-service.ts b/arduino-ide-extension/src/common/protocol/sketches-service.ts
index 94bc8eef..9b84b6e0 100644
--- a/arduino-ide-extension/src/common/protocol/sketches-service.ts
+++ b/arduino-ide-extension/src/common/protocol/sketches-service.ts
@@ -74,7 +74,7 @@ export namespace Sketch {
     export namespace Extensions {
         export const MAIN = ['.ino', '.pde'];
         export const SOURCE = ['.c', '.cpp', '.s'];
-        export const ADDITIONAL = ['.h', '.c', '.hpp', '.hh', '.cpp', '.s'];
+        export const ADDITIONAL = ['.h', '.c', '.hpp', '.hh', '.cpp', '.s', '.json'];
         export const ALL = Array.from(new Set([...MAIN, ...SOURCE, ...ADDITIONAL]));
     }
     export function isInSketch(uri: string | URI, sketch: Sketch): boolean {
diff --git a/electron/build/template-package.json b/electron/build/template-package.json
index 4b6c7ebc..4879609f 100644
--- a/electron/build/template-package.json
+++ b/electron/build/template-package.json
@@ -138,6 +138,8 @@
   "theiaPlugins": {
     "vscode-builtin-cpp": "http://open-vsx.org/api/vscode/cpp/1.44.2/file/vscode.cpp-1.44.2.vsix",
     "vscode-arduino-language-server": "https://downloads.arduino.cc/vscode-arduino-language-server/nightly/vscode-arduino-language-server-0.0.1.vsix",
+    "vscode-builtin-json": "https://open-vsx.org/api/vscode/json/1.46.1/file/vscode.json-1.46.1.vsix",
+    "vscode-builtin-json-language-features": "https://open-vsx.org/api/vscode/json-language-features/1.46.1/file/vscode.json-language-features-1.46.1.vsix",
     "cortex-debug": "https://open-vsx.org/api/marus25/cortex-debug/0.3.7/file/marus25.cortex-debug-0.3.7.vsix"
   }
 }
diff --git a/package.json b/package.json
index 61a7f40b..8e97d5ee 100644
--- a/package.json
+++ b/package.json
@@ -37,6 +37,8 @@
   "theiaPlugins": {
     "vscode-builtin-cpp": "http://open-vsx.org/api/vscode/cpp/1.44.2/file/vscode.cpp-1.44.2.vsix",
     "vscode-arduino-language-server": "https://downloads.arduino.cc/vscode-arduino-language-server/nightly/vscode-arduino-language-server-0.0.1.vsix",
+    "vscode-builtin-json": "https://open-vsx.org/api/vscode/json/1.46.1/file/vscode.json-1.46.1.vsix",
+    "vscode-builtin-json-language-features": "https://open-vsx.org/api/vscode/json-language-features/1.46.1/file/vscode.json-language-features-1.46.1.vsix",
     "cortex-debug": "https://open-vsx.org/api/marus25/cortex-debug/0.3.7/file/marus25.cortex-debug-0.3.7.vsix"
   }
 }