diff --git a/.eslintignore b/.eslintignore
index 3df656a84..96158845f 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -115,6 +115,7 @@ ReactNativeClient/lib/services/keychain/KeychainServiceDriver.node.js
 ReactNativeClient/lib/services/keychain/KeychainServiceDriverBase.js
 ReactNativeClient/lib/services/ResourceEditWatcher.js
 ReactNativeClient/lib/services/rest/actionApi.desktop.js
+ReactNativeClient/lib/services/rest/errors.js
 ReactNativeClient/lib/services/SettingUtils.js
 ReactNativeClient/lib/services/UndoRedoService.js
 ReactNativeClient/lib/ShareExtension.js
diff --git a/.gitignore b/.gitignore
index 6b2b19d1d..d95cdf5c9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -105,6 +105,7 @@ ReactNativeClient/lib/services/keychain/KeychainServiceDriver.node.js
 ReactNativeClient/lib/services/keychain/KeychainServiceDriverBase.js
 ReactNativeClient/lib/services/ResourceEditWatcher.js
 ReactNativeClient/lib/services/rest/actionApi.desktop.js
+ReactNativeClient/lib/services/rest/errors.js
 ReactNativeClient/lib/services/SettingUtils.js
 ReactNativeClient/lib/services/UndoRedoService.js
 ReactNativeClient/lib/ShareExtension.js
diff --git a/ReactNativeClient/lib/services/ExternalEditWatcher.js b/ReactNativeClient/lib/services/ExternalEditWatcher.js
index ccea96d8b..c7d81d1b3 100644
--- a/ReactNativeClient/lib/services/ExternalEditWatcher.js
+++ b/ReactNativeClient/lib/services/ExternalEditWatcher.js
@@ -9,6 +9,7 @@ const spawn = require('child_process').spawn;
 const chokidar = require('chokidar');
 const { bridge } = require('electron').remote.require('./bridge');
 const { time } = require('lib/time-utils.js');
+const { ErrorNotFound } = require('./rest/errors');
 
 class ExternalEditWatcher {
 	constructor() {
@@ -27,16 +28,22 @@ class ExternalEditWatcher {
 	}
 
 	externalApi() {
+		const loadNote = async (noteId) => {
+			const note = await Note.load(noteId);
+			if (!note) throw new ErrorNotFound(`No such note: ${noteId}`);
+			return note;
+		};
+
 		return {
 			openAndWatch: async ({ noteId }) => {
-				const note = await Note.load(noteId);
+				const note = await loadNote(noteId);
 				return this.openAndWatch(note);
 			},
 			stopWatching: async ({ noteId }) => {
 				return this.stopWatching(noteId);
 			},
 			noteIsWatched: async ({ noteId }) => {
-				const note = await Note.load(noteId);
+				const note = await loadNote(noteId);
 				return this.noteIsWatched(note);
 			},
 		};
diff --git a/ReactNativeClient/lib/services/rest/Api.js b/ReactNativeClient/lib/services/rest/Api.js
index 4b93b90dd..e315c2168 100644
--- a/ReactNativeClient/lib/services/rest/Api.js
+++ b/ReactNativeClient/lib/services/rest/Api.js
@@ -24,38 +24,7 @@ const { FoldersScreenUtils } = require('lib/folders-screen-utils.js');
 const uri2path = require('file-uri-to-path');
 const { MarkupToHtml } = require('lib/joplin-renderer');
 const { uuid } = require('lib/uuid');
-
-class ApiError extends Error {
-	constructor(message, httpCode = 400) {
-		super(message);
-		this.httpCode_ = httpCode;
-	}
-
-	get httpCode() {
-		return this.httpCode_;
-	}
-}
-
-class ErrorMethodNotAllowed extends ApiError {
-	constructor(message = 'Method Not Allowed') {
-		super(message, 405);
-	}
-}
-class ErrorNotFound extends ApiError {
-	constructor(message = 'Not Found') {
-		super(message, 404);
-	}
-}
-class ErrorForbidden extends ApiError {
-	constructor(message = 'Forbidden') {
-		super(message, 403);
-	}
-}
-class ErrorBadRequest extends ApiError {
-	constructor(message = 'Bad Request') {
-		super(message, 400);
-	}
-}
+const { ErrorMethodNotAllowed, ErrorForbidden, ErrorBadRequest, ErrorNotFound } = require('./errors');
 
 class Api {
 	constructor(token = null, actionApi = null) {
diff --git a/ReactNativeClient/lib/services/rest/errors.ts b/ReactNativeClient/lib/services/rest/errors.ts
new file mode 100644
index 000000000..321ab792c
--- /dev/null
+++ b/ReactNativeClient/lib/services/rest/errors.ts
@@ -0,0 +1,33 @@
+class ApiError extends Error {
+	private httpCode_:number;
+
+	constructor(message:string, httpCode:number = 400) {
+		super(message);
+		this.httpCode_ = httpCode;
+	}
+
+	get httpCode() {
+		return this.httpCode_;
+	}
+}
+
+export class ErrorMethodNotAllowed extends ApiError {
+	constructor(message = 'Method Not Allowed') {
+		super(message, 405);
+	}
+}
+export class ErrorNotFound extends ApiError {
+	constructor(message = 'Not Found') {
+		super(message, 404);
+	}
+}
+export class ErrorForbidden extends ApiError {
+	constructor(message = 'Forbidden') {
+		super(message, 403);
+	}
+}
+export class ErrorBadRequest extends ApiError {
+	constructor(message = 'Bad Request') {
+		super(message, 400);
+	}
+}