diff --git a/db/migrations/0200__create_hidden_subtree.js b/db/migrations/0200__create_hidden_subtree.js
index aba83ac4e..990566283 100644
--- a/db/migrations/0200__create_hidden_subtree.js
+++ b/db/migrations/0200__create_hidden_subtree.js
@@ -1,5 +1,5 @@
 module.exports = () => {
-    const hiddenSubtreeService = require('../../src/services/hidden_subtree.js');
+    const hiddenSubtreeService = require('../../src/services/hidden_subtree');
     const cls = require("../../src/services/cls");
     const beccaLoader = require("../../src/becca/becca_loader");
 
diff --git a/dump-db/dump-db.js b/dump-db/dump-db.js
index ece36f39e..2e37486c0 100755
--- a/dump-db/dump-db.js
+++ b/dump-db/dump-db.js
@@ -2,7 +2,7 @@
 
 const yargs = require('yargs/yargs')
 const { hideBin } = require('yargs/helpers')
-const dumpService = require("./inc/dump.js");
+const dumpService = require("./inc/dump");
 
 yargs(hideBin(process.argv))
     .command('$0 <path_to_document> <target_directory>', 'dump the contents of document.db into the target directory', (yargs) => {
diff --git a/dump-db/inc/data_key.js b/dump-db/inc/data_key.js
index c879bafad..fe47ddd6f 100644
--- a/dump-db/inc/data_key.js
+++ b/dump-db/inc/data_key.js
@@ -1,6 +1,6 @@
 const crypto = require("crypto");
-const sql = require("./sql.js");
-const decryptService = require("./decrypt.js");
+const sql = require("./sql");
+const decryptService = require("./decrypt");
 
 function getDataKey(password) {
     if (!password) {
diff --git a/dump-db/inc/dump.js b/dump-db/inc/dump.js
index 6145f040a..cd6ba5534 100644
--- a/dump-db/inc/dump.js
+++ b/dump-db/inc/dump.js
@@ -1,9 +1,9 @@
 const fs = require("fs");
 const sanitize = require("sanitize-filename");
-const sql = require("./sql.js");
-const decryptService = require("./decrypt.js");
-const dataKeyService = require("./data_key.js");
-const extensionService = require("./extension.js");
+const sql = require("./sql");
+const decryptService = require("./decrypt");
+const dataKeyService = require("./data_key");
+const extensionService = require("./extension");
 
 function dumpDocument(documentPath, targetPath, options) {
     const stats = {
diff --git a/spec/search/search.spec.js b/spec/search/search.spec.js
index e74d48107..ce826ed16 100644
--- a/spec/search/search.spec.js
+++ b/spec/search/search.spec.js
@@ -4,7 +4,7 @@ const Branch = require('../../src/becca/entities/branch');
 const SearchContext = require('../../src/services/search/search_context');
 const dateUtils = require('../../src/services/date_utils');
 const becca = require('../../src/becca/becca');
-const {NoteBuilder, findNoteByTitle, note} = require('./becca_mocking.js');
+const {NoteBuilder, findNoteByTitle, note} = require('./becca_mocking');
 
 describe("Search", () => {
     let rootNote;
diff --git a/spec/search/value_extractor.spec.js b/spec/search/value_extractor.spec.js
index 1e664279f..04fe3c303 100644
--- a/spec/search/value_extractor.spec.js
+++ b/spec/search/value_extractor.spec.js
@@ -1,4 +1,4 @@
-const {note} = require('./becca_mocking.js');
+const {note} = require('./becca_mocking');
 const ValueExtractor = require('../../src/services/search/value_extractor');
 const becca = require('../../src/becca/becca');
 const SearchContext = require("../../src/services/search/search_context");
diff --git a/src/becca/becca_service.js b/src/becca/becca_service.js
index 4337903b0..d666c502a 100644
--- a/src/becca/becca_service.js
+++ b/src/becca/becca_service.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const becca = require('./becca.js');
+const becca = require('./becca');
 const cls = require('../services/cls');
 const protectedSessionService = require('../services/protected_session');
 const log = require('../services/log');
diff --git a/src/becca/entities/branch.js b/src/becca/entities/branch.js
index 691a46e39..2ed3ec070 100644
--- a/src/becca/entities/branch.js
+++ b/src/becca/entities/branch.js
@@ -4,7 +4,7 @@ const Note = require('./note');
 const AbstractEntity = require("./abstract_entity");
 const sql = require("../../services/sql");
 const dateUtils = require("../../services/date_utils");
-const utils = require("../../services/utils.js");
+const utils = require("../../services/utils");
 const TaskContext = require("../../services/task_context");
 const cls = require("../../services/cls");
 const log = require("../../services/log");
diff --git a/src/becca/similarity.js b/src/becca/similarity.js
index f270960c0..efb8734d6 100644
--- a/src/becca/similarity.js
+++ b/src/becca/similarity.js
@@ -1,6 +1,6 @@
 const becca = require('./becca');
 const log = require('../services/log');
-const beccaService = require('./becca_service.js');
+const beccaService = require('./becca_service');
 const dateUtils = require('../services/date_utils');
 const { JSDOM } = require("jsdom");
 
diff --git a/src/etapi/app_info.js b/src/etapi/app_info.js
index ede96d792..3dc4481ac 100644
--- a/src/etapi/app_info.js
+++ b/src/etapi/app_info.js
@@ -1,5 +1,5 @@
 const appInfo = require('../services/app_info');
-const eu = require("./etapi_utils.js");
+const eu = require("./etapi_utils");
 
 function register(router) {
     eu.route(router, 'get', '/etapi/app-info', (req, res, next) => {
diff --git a/src/public/app/widgets/attribute_widgets/attribute_editor.js b/src/public/app/widgets/attribute_widgets/attribute_editor.js
index 59e8b1906..d3bf0522b 100644
--- a/src/public/app/widgets/attribute_widgets/attribute_editor.js
+++ b/src/public/app/widgets/attribute_widgets/attribute_editor.js
@@ -357,7 +357,7 @@ export default class AttributeEditorWidget extends NoteContextAwareWidget {
         // disable spellcheck for attribute editor
         this.textEditor.editing.view.change(writer => writer.setAttribute('spellcheck', 'false', this.textEditor.editing.view.document.getRoot()));
 
-        //await import(/* webpackIgnore: true */'../../libraries/ckeditor/inspector.js');
+        //await import(/* webpackIgnore: true */'../../libraries/ckeditor/inspector');
         //CKEditorInspector.attach(this.textEditor);
     }
 
diff --git a/src/public/app/widgets/note_tree.js b/src/public/app/widgets/note_tree.js
index b60e981ff..04524a645 100644
--- a/src/public/app/widgets/note_tree.js
+++ b/src/public/app/widgets/note_tree.js
@@ -452,7 +452,7 @@ export default class NoteTreeWidget extends NoteContextAwareWidget {
                     if (dataTransfer && dataTransfer.files && dataTransfer.files.length > 0) {
                         const files = [...dataTransfer.files]; // chrome has issue that dataTransfer.files empties after async operation
 
-                        const importService = await import('../services/import.js');
+                        const importService = await import('../services/import');
 
                         importService.uploadFiles(node.data.noteId, files, {
                             safeImport: true,
diff --git a/src/public/app/widgets/type_widgets/editable_text.js b/src/public/app/widgets/type_widgets/editable_text.js
index c41d020aa..8f53e7207 100644
--- a/src/public/app/widgets/type_widgets/editable_text.js
+++ b/src/public/app/widgets/type_widgets/editable_text.js
@@ -132,7 +132,7 @@ export default class EditableTextTypeWidget extends AbstractTextTypeWidget {
         this.textEditor.model.document.on('change:data', () => this.spacedUpdate.scheduleUpdate());
 
         if (glob.isDev && ENABLE_INSPECTOR) {
-            await import(/* webpackIgnore: true */'../../../libraries/ckeditor/inspector.js');
+            await import(/* webpackIgnore: true */'../../../libraries/ckeditor/inspector');
             CKEditorInspector.attach(this.textEditor);
         }
     }
diff --git a/src/routes/api/attributes.js b/src/routes/api/attributes.js
index 60339ad71..ec4ab2c3f 100644
--- a/src/routes/api/attributes.js
+++ b/src/routes/api/attributes.js
@@ -5,8 +5,8 @@ const log = require('../../services/log');
 const attributeService = require('../../services/attributes');
 const Attribute = require('../../becca/entities/attribute');
 const becca = require("../../becca/becca");
-const ValidationError = require("../../public/app/services/validation_error.js");
-const NotFoundError = require("../../errors/not_found_error.js");
+const ValidationError = require("../../errors/validation_error");
+const NotFoundError = require("../../errors/not_found_error");
 
 function getEffectiveNoteAttributes(req) {
     const note = becca.getNote(req.params.noteId);
diff --git a/src/routes/api/branches.js b/src/routes/api/branches.js
index 8ef10b119..cb3f31b71 100644
--- a/src/routes/api/branches.js
+++ b/src/routes/api/branches.js
@@ -8,9 +8,9 @@ const noteService = require('../../services/notes');
 const becca = require('../../becca/becca');
 const TaskContext = require('../../services/task_context');
 const branchService = require("../../services/branches");
-const log = require("../../services/log.js");
-const ValidationError = require("../../public/app/services/validation_error.js");
-const NotFoundError = require("../../errors/not_found_error.js");
+const log = require("../../services/log");
+const ValidationError = require("../../errors/validation_error");
+const NotFoundError = require("../../errors/not_found_error");
 
 /**
  * Code in this file deals with moving and cloning branches. Relationship between note and parent note is unique
diff --git a/src/routes/api/export.js b/src/routes/api/export.js
index 0a22233a8..365c7e185 100644
--- a/src/routes/api/export.js
+++ b/src/routes/api/export.js
@@ -6,7 +6,7 @@ const opmlExportService = require('../../services/export/opml');
 const becca = require('../../becca/becca');
 const TaskContext = require("../../services/task_context");
 const log = require("../../services/log");
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 function exportBranch(req, res) {
     const {branchId, type, format, version, taskId} = req.params;
diff --git a/src/routes/api/files.js b/src/routes/api/files.js
index 3b9bef762..7e41af4ae 100644
--- a/src/routes/api/files.js
+++ b/src/routes/api/files.js
@@ -10,7 +10,7 @@ const { Readable } = require('stream');
 const chokidar = require('chokidar');
 const ws = require('../../services/ws');
 const becca = require("../../becca/becca");
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 function updateFile(req) {
     const {noteId} = req.params;
diff --git a/src/routes/api/image.js b/src/routes/api/image.js
index 619f7b21e..aa6151ce6 100644
--- a/src/routes/api/image.js
+++ b/src/routes/api/image.js
@@ -4,8 +4,8 @@ const imageService = require('../../services/image');
 const becca = require('../../becca/becca');
 const RESOURCE_DIR = require('../../services/resource_dir').RESOURCE_DIR;
 const fs = require('fs');
-const ValidationError = require("../../public/app/services/validation_error.js");
-const NotFoundError = require("../../errors/not_found_error.js");
+const ValidationError = require("../../errors/validation_error");
+const NotFoundError = require("../../errors/not_found_error");
 
 function returnImage(req, res) {
     const image = becca.getNote(req.params.noteId);
diff --git a/src/routes/api/import.js b/src/routes/api/import.js
index 930758ce8..f62f37b7c 100644
--- a/src/routes/api/import.js
+++ b/src/routes/api/import.js
@@ -10,8 +10,8 @@ const becca = require('../../becca/becca');
 const beccaLoader = require('../../becca/becca_loader');
 const log = require('../../services/log');
 const TaskContext = require('../../services/task_context');
-const ValidationError = require("../../public/app/services/validation_error.js");
-const NotFoundError = require("../../errors/not_found_error.js");
+const ValidationError = require("../../errors/validation_error");
+const NotFoundError = require("../../errors/not_found_error");
 
 async function importToBranch(req) {
     const {parentNoteId} = req.params;
diff --git a/src/routes/api/note_map.js b/src/routes/api/note_map.js
index f9fe9bc44..4485130a0 100644
--- a/src/routes/api/note_map.js
+++ b/src/routes/api/note_map.js
@@ -2,7 +2,7 @@
 
 const becca = require("../../becca/becca");
 const { JSDOM } = require("jsdom");
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 function buildDescendantCountMap() {
     const noteIdToCountMap = {};
diff --git a/src/routes/api/notes.js b/src/routes/api/notes.js
index 1033d3663..ba112b034 100644
--- a/src/routes/api/notes.js
+++ b/src/routes/api/notes.js
@@ -6,11 +6,10 @@ const sql = require('../../services/sql');
 const utils = require('../../services/utils');
 const log = require('../../services/log');
 const TaskContext = require('../../services/task_context');
-const protectedSessionService = require('../../services/protected_session');
 const fs = require('fs');
 const becca = require("../../becca/becca");
-const ValidationError = require("../../public/app/services/validation_error.js");
-const NotFoundError = require("../../errors/not_found_error.js");
+const ValidationError = require("../../errors/validation_error");
+const NotFoundError = require("../../errors/not_found_error");
 
 function getNote(req) {
     const noteId = req.params.noteId;
diff --git a/src/routes/api/options.js b/src/routes/api/options.js
index 4c2add9f3..a176bb45f 100644
--- a/src/routes/api/options.js
+++ b/src/routes/api/options.js
@@ -3,7 +3,7 @@
 const optionService = require('../../services/options');
 const log = require('../../services/log');
 const searchService = require('../../services/search/services/search');
-const ValidationError = require("../../public/app/services/validation_error.js");
+const ValidationError = require("../../errors/validation_error");
 
 // options allowed to be updated directly in options dialog
 const ALLOWED_OPTIONS = new Set([
diff --git a/src/routes/api/password.js b/src/routes/api/password.js
index 7fe1203cb..289a18716 100644
--- a/src/routes/api/password.js
+++ b/src/routes/api/password.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const passwordService = require('../../services/password');
-const ValidationError = require("../../public/app/services/validation_error.js");
+const ValidationError = require("../../errors/validation_error");
 
 function changePassword(req) {
     if (passwordService.isPasswordSet()) {
diff --git a/src/routes/api/search.js b/src/routes/api/search.js
index 8356b14f0..b9c1f5412 100644
--- a/src/routes/api/search.js
+++ b/src/routes/api/search.js
@@ -6,8 +6,8 @@ const searchService = require('../../services/search/services/search');
 const bulkActionService = require("../../services/bulk_actions");
 const cls = require("../../services/cls");
 const {formatAttrForSearch} = require("../../services/attribute_formatter");
-const ValidationError = require("../../public/app/services/validation_error.js");
-const NotFoundError = require("../../errors/not_found_error.js");
+const ValidationError = require("../../errors/validation_error");
+const NotFoundError = require("../../errors/not_found_error");
 
 function searchFromNote(req) {
     const note = becca.getNote(req.params.noteId);
diff --git a/src/routes/api/similar_notes.js b/src/routes/api/similar_notes.js
index 524bfc493..e27968ebe 100644
--- a/src/routes/api/similar_notes.js
+++ b/src/routes/api/similar_notes.js
@@ -2,7 +2,7 @@
 
 const similarityService = require('../../becca/similarity');
 const becca = require("../../becca/becca");
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 async function getSimilarNotes(req) {
     const noteId = req.params.noteId;
diff --git a/src/routes/api/sql.js b/src/routes/api/sql.js
index 25bf111f7..09e14cc86 100644
--- a/src/routes/api/sql.js
+++ b/src/routes/api/sql.js
@@ -2,7 +2,7 @@
 
 const sql = require('../../services/sql');
 const becca = require("../../becca/becca");
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 function getSchema() {
     const tableNames = sql.getColumn(`SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%' ORDER BY name`);
diff --git a/src/routes/api/stats.js b/src/routes/api/stats.js
index 4276655eb..43aec3014 100644
--- a/src/routes/api/stats.js
+++ b/src/routes/api/stats.js
@@ -1,6 +1,6 @@
 const sql = require('../../services/sql');
 const becca = require('../../becca/becca');
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 function getNoteSize(req) {
     const {noteId} = req.params;
diff --git a/src/routes/api/tree.js b/src/routes/api/tree.js
index 5f323570c..82b3ace04 100644
--- a/src/routes/api/tree.js
+++ b/src/routes/api/tree.js
@@ -2,7 +2,7 @@
 
 const becca = require('../../becca/becca');
 const log = require('../../services/log');
-const NotFoundError = require("../../errors/not_found_error.js");
+const NotFoundError = require("../../errors/not_found_error");
 
 function getNotesAndBranchesAndAttributes(noteIds) {
     noteIds = new Set(noteIds);
diff --git a/src/routes/login.js b/src/routes/login.js
index f00e455df..f824931c6 100644
--- a/src/routes/login.js
+++ b/src/routes/login.js
@@ -6,7 +6,7 @@ const myScryptService = require('../services/my_scrypt');
 const log = require('../services/log');
 const passwordService = require("../services/password");
 const assetPath = require("../services/asset_path");
-const ValidationError = require("../public/app/services/validation_error.js");
+const ValidationError = require("../errors/validation_error");
 
 function loginPage(req, res) {
     res.render('login', {
diff --git a/src/routes/routes.js b/src/routes/routes.js
index bb3f1d044..ff1dde1fa 100644
--- a/src/routes/routes.js
+++ b/src/routes/routes.js
@@ -5,7 +5,7 @@ const loginRoute = require('./login');
 const indexRoute = require('./index');
 const utils = require('../services/utils');
 const multer = require('multer');
-const ValidationError = require("../errors/validation_error.js");
+const ValidationError = require("../errors/validation_error");
 
 // API routes
 const treeApiRoute = require('./api/tree');
@@ -62,7 +62,7 @@ const csurf = require('csurf');
 const {createPartialContentHandler} = require("express-partial-content");
 const rateLimit = require("express-rate-limit");
 const AbstractEntity = require("../becca/entities/abstract_entity");
-const NotFoundError = require("../errors/not_found_error.js");
+const NotFoundError = require("../errors/not_found_error");
 
 const csrfMiddleware = csurf({
     cookie: true,
diff --git a/src/services/hidden_subtree.js b/src/services/hidden_subtree.js
index 73bdebec3..4b2ae362f 100644
--- a/src/services/hidden_subtree.js
+++ b/src/services/hidden_subtree.js
@@ -1,6 +1,6 @@
 const becca = require("../becca/becca");
 const noteService = require("./notes");
-const log = require("./log.js");
+const log = require("./log");
 
 const LBTPL_ROOT = "lbTplRoot";
 const LBTPL_BASE = "lbTplBase";
diff --git a/src/services/notes.js b/src/services/notes.js
index 72fb46383..77b16c236 100644
--- a/src/services/notes.js
+++ b/src/services/notes.js
@@ -18,8 +18,8 @@ const Branch = require('../becca/entities/branch');
 const Note = require('../becca/entities/note');
 const Attribute = require('../becca/entities/attribute');
 const dayjs = require("dayjs");
-const htmlSanitizer = require("./html_sanitizer.js");
-const ValidationError = require("../errors/validation_error.js");
+const htmlSanitizer = require("./html_sanitizer");
+const ValidationError = require("../errors/validation_error");
 
 function getNewNotePosition(parentNoteId) {
     const note = becca.notes[parentNoteId];
diff --git a/src/services/search/services/parse.js b/src/services/search/services/parse.js
index ad88449e2..2f72e0b1b 100644
--- a/src/services/search/services/parse.js
+++ b/src/services/search/services/parse.js
@@ -12,7 +12,7 @@ const PropertyComparisonExp = require('../expressions/property_comparison');
 const AttributeExistsExp = require('../expressions/attribute_exists');
 const LabelComparisonExp = require('../expressions/label_comparison');
 const NoteFlatTextExp = require('../expressions/note_flat_text');
-const NoteContentFulltextExp = require('../expressions/note_content_fulltext.js');
+const NoteContentFulltextExp = require('../expressions/note_content_fulltext');
 const OrderByAndLimitExp = require('../expressions/order_by_and_limit');
 const AncestorExp = require("../expressions/ancestor");
 const buildComparator = require('./build_comparator');
diff --git a/src/services/search/services/search.js b/src/services/search/services/search.js
index 42897ebc5..dee2816c6 100644
--- a/src/services/search/services/search.js
+++ b/src/services/search/services/search.js
@@ -10,7 +10,7 @@ const becca = require('../../../becca/becca');
 const beccaService = require('../../../becca/becca_service');
 const utils = require('../../utils');
 const log = require('../../log');
-const scriptService = require("../../script.js");
+const scriptService = require("../../script");
 
 function searchFromNote(note) {
     let searchResultNoteIds, highlightedTokens;
diff --git a/src/services/special_notes.js b/src/services/special_notes.js
index 5e318bd11..da272cfe0 100644
--- a/src/services/special_notes.js
+++ b/src/services/special_notes.js
@@ -4,7 +4,7 @@ const becca = require("../becca/becca");
 const noteService = require("./notes");
 const cls = require("./cls");
 const dateUtils = require("./date_utils");
-const log = require("./log.js");
+const log = require("./log");
 const hiddenSubtreeService = require("./hidden_subtree");
 
 function getInboxNote(date) {