diff --git a/src/node/db/API.js b/src/node/db/API.js
index 3f92c47dd..b9efb5411 100644
--- a/src/node/db/API.js
+++ b/src/node/db/API.js
@@ -33,7 +33,7 @@ const exportTxt = require('../utils/ExportTxt');
 const importHtml = require('../utils/ImportHtml');
 const cleanText = require('./Pad').cleanText;
 const PadDiff = require('../utils/padDiff');
-const { checkValidRev, isInt } = require('../utils/checkValidRev');
+const {checkValidRev, isInt} = require('../utils/checkValidRev');
 
 /* ********************
  * GROUP FUNCTIONS ****
@@ -193,6 +193,13 @@ Example returns:
 {code: 1, message:"padID does not exist", data: null}
 {code: 1, message:"text too long", data: null}
 */
+/**
+ *
+ * @param {String} padID the id of the pad
+ * @param {String} text the text of the pad
+ * @param {String} authorId the id of the author, defaulting to empty string
+ * @returns {Promise<void>}
+ */
 exports.setText = async (padID, text, authorId = '') => {
   // text is required
   if (typeof text !== 'string') {
@@ -214,7 +221,10 @@ Example returns:
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
 {code: 1, message:"text too long", data: null}
-*/
+ @param {String} padID the id of the pad
+ @param {String} text the text of the pad
+ @param {String} authorId the id of the author, defaulting to empty string
+ */
 exports.appendText = async (padID, text, authorId = '') => {
   // text is required
   if (typeof text !== 'string') {
@@ -233,6 +243,9 @@ Example returns:
 
 {code: 0, message:"ok", data: {text:"Welcome <strong>Text</strong>"}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
+ @param {String} rev the revision number, defaulting to the latest revision
+ @return {Promise<{html: string}>} the html of the pad
 */
 exports.getHTML = async (padID, rev) => {
   if (rev !== undefined) {
@@ -265,6 +278,10 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
+
+ @param {String} padID the id of the pad
+ @param {String} html the html of the pad
+ @param {String} authorId the id of the author, defaulting to empty string
 */
 exports.setHTML = async (padID, html, authorId = '') => {
   // html string is required
@@ -303,6 +320,9 @@ Example returns:
 {code: 1, message:"start is higher or equal to the current chatHead", data: null}
 
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
+ @param {Number} start the start point of the chat-history
+ @param {Number} end the end point of the chat-history
 */
 exports.getChatHistory = async (padID, start, end) => {
   if (start && end) {
@@ -349,6 +369,10 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
+ @param {String} text the text of the chat-message
+ @param {String} authorID the id of the author
+ @param {Number} time the timestamp of the chat-message
 */
 exports.appendChatMessage = async (padID, text, authorID, time) => {
   // text is required
@@ -378,6 +402,7 @@ Example returns:
 
 {code: 0, message:"ok", data: {revisions: 56}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
 */
 exports.getRevisionsCount = async (padID) => {
   // get the pad
@@ -392,6 +417,7 @@ Example returns:
 
 {code: 0, message:"ok", data: {savedRevisions: 42}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
 */
 exports.getSavedRevisionsCount = async (padID) => {
   // get the pad
@@ -406,6 +432,7 @@ Example returns:
 
 {code: 0, message:"ok", data: {savedRevisions: [2, 42, 1337]}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
 */
 exports.listSavedRevisions = async (padID) => {
   // get the pad
@@ -420,6 +447,8 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
+    @param {String} padID the id of the pad
+     @param {Number} rev the revision number, defaulting to the latest revision
 */
 exports.saveRevision = async (padID, rev) => {
   // check if rev is a number
@@ -451,6 +480,8 @@ Example returns:
 
 {code: 0, message:"ok", data: {lastEdited: 1340815946602}}
 {code: 1, message:"padID does not exist", data: null}
+    @param {String} padID the id of the pad
+ @return {Promise<{lastEdited: number}>} the timestamp of the last revision of the pad
 */
 exports.getLastEdited = async (padID) => {
   // get the pad
@@ -466,6 +497,9 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"pad does already exist", data: null}
+ @param {String} padName the name of the new pad
+    @param {String} text the initial text of the pad
+     @param {String} authorId the id of the author, defaulting to empty string
 */
 exports.createPad = async (padID, text, authorId = '') => {
   if (padID) {
@@ -491,6 +525,7 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
 */
 exports.deletePad = async (padID) => {
   const pad = await getPadSafe(padID, true);
@@ -504,6 +539,9 @@ exports.deletePad = async (padID) => {
 
  {code:0, message:"ok", data:null}
  {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
+ @param {Number} rev the revision number, defaulting to the latest revision
+ @param {String} authorId the id of the author, defaulting to empty string
  */
 exports.restoreRevision = async (padID, rev, authorId = '') => {
   // check if rev is a number
@@ -568,6 +606,9 @@ Example returns:
 
 {code: 0, message:"ok", data: {padID: destinationID}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} sourceID the id of the source pad
+ @param {String} destinationID the id of the destination pad
+ @param {Boolean} force whether to overwrite the destination pad if it exists
 */
 exports.copyPad = async (sourceID, destinationID, force) => {
   const pad = await getPadSafe(sourceID, true);
@@ -582,6 +623,10 @@ Example returns:
 
 {code: 0, message:"ok", data: {padID: destinationID}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} sourceID the id of the source pad
+ @param {String} destinationID the id of the destination pad
+ @param {Boolean} force whether to overwrite the destination pad if it exists
+ @param {String} authorId the id of the author, defaulting to empty string
 */
 exports.copyPadWithoutHistory = async (sourceID, destinationID, force, authorId = '') => {
   const pad = await getPadSafe(sourceID, true);
@@ -596,6 +641,9 @@ Example returns:
 
 {code: 0, message:"ok", data: {padID: destinationID}}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} sourceID the id of the source pad
+ @param {String} destinationID the id of the destination pad
+ @param {Boolean} force whether to overwrite the destination pad if it exists
 */
 exports.movePad = async (sourceID, destinationID, force) => {
   const pad = await getPadSafe(sourceID, true);
@@ -610,6 +658,7 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
+ @param {String} padID the id of the pad
 */
 exports.getReadOnlyID = async (padID) => {
   // we don't need the pad object, but this function does all the security stuff for us
@@ -628,6 +677,7 @@ Example returns:
 
 {code: 0, message:"ok", data: {padID: padID}}
 {code: 1, message:"padID does not exist", data: null}
+    @param {String} roID the readonly id of the pad
 */
 exports.getPadID = async (roID) => {
   // get the PadId
@@ -646,6 +696,8 @@ Example returns:
 
 {code: 0, message:"ok", data: null}
 {code: 1, message:"padID does not exist", data: null}
+    @param {String} padID the id of the pad
+     @param {Boolean} publicStatus the public status of the pad
 */
 exports.setPublicStatus = async (padID, publicStatus) => {
   // ensure this is a group pad
@@ -669,6 +721,7 @@ Example returns:
 
 {code: 0, message:"ok", data: {publicStatus: true}}
 {code: 1, message:"padID does not exist", data: null}
+     @param {String} padID the id of the pad
 */
 exports.getPublicStatus = async (padID) => {
   // ensure this is a group pad
@@ -686,6 +739,7 @@ Example returns:
 
 {code: 0, message:"ok", data: {authorIDs : ["a.s8oes9dhwrvt0zif", "a.akf8finncvomlqva"]}
 {code: 1, message:"padID does not exist", data: null}
+     @param {String} padID the id of the pad
 */
 exports.listAuthorsOfPad = async (padID) => {
   // get the pad
@@ -715,6 +769,8 @@ Example returns:
 
 {code: 0, message:"ok"}
 {code: 1, message:"padID does not exist"}
+     @param {String} padID the id of the pad
+     @param {String} msg the message to send
 */
 
 exports.sendClientsMessage = async (padID, msg) => {
@@ -740,6 +796,8 @@ Example returns:
 
 {code: 0, message:"ok", data: {chatHead: 42}}
 {code: 1, message:"padID does not exist", data: null}
+     @param {String} padID the id of the pad
+     @return {Promise<{chatHead: number}>} the chatHead of the pad
 */
 exports.getChatHead = async (padID) => {
   // get the pad
@@ -763,7 +821,9 @@ Example returns:
   }
 }
 {"code":4,"message":"no or wrong API Key","data":null}
-
+  @param {String} padID the id of the pad
+ @param {Number} startRev the start revision number
+ @param {Number} endRev the end revision number
 */
 exports.createDiffHTML = async (padID, startRev, endRev) => {
   // check if startRev is a number
@@ -779,11 +839,9 @@ exports.createDiffHTML = async (padID, startRev, endRev) => {
   // get the pad
   const pad = await getPadSafe(padID, true);
   const headRev = pad.getHeadRevisionNumber();
-  if (startRev > headRev)
-    startRev = headRev;
+  if (startRev > headRev) startRev = headRev;
 
-  if (endRev > headRev)
-    endRev = headRev;
+  if (endRev > headRev) endRev = headRev;
 
   let padDiff;
   try {
@@ -810,7 +868,6 @@ exports.createDiffHTML = async (padID, startRev, endRev) => {
  {"code":0,"message":"ok","data":{"totalPads":3,"totalSessions": 2,"totalActivePads": 1}}
  {"code":4,"message":"no or wrong API Key","data":null}
  */
-
 exports.getStats = async () => {
   const sessionInfos = padMessageHandler.sessioninfos;
 
diff --git a/src/node/db/AuthorManager.js b/src/node/db/AuthorManager.js
index 7049be5db..7413b5806 100644
--- a/src/node/db/AuthorManager.js
+++ b/src/node/db/AuthorManager.js
@@ -93,6 +93,7 @@ exports.getColorPalette = () => [
 
 /**
  * Checks if the author exists
+ * @param {String} authorID The id of the author
  */
 exports.doesAuthorExist = async (authorID) => {
   const author = await db.get(`globalAuthor:${authorID}`);
@@ -100,50 +101,12 @@ exports.doesAuthorExist = async (authorID) => {
   return author != null;
 };
 
-/* exported for backwards compatibility */
+/**
+ exported for backwards compatibility
+ @param {String} authorID The id of the author
+  */
 exports.doesAuthorExists = exports.doesAuthorExist;
 
-const getAuthor4Token = async (token) => {
-  const author = await mapAuthorWithDBKey('token2author', token);
-
-  // return only the sub value authorID
-  return author ? author.authorID : author;
-};
-
-exports.getAuthorId = async (token, user) => {
-  const context = {dbKey: token, token, user};
-  let [authorId] = await hooks.aCallFirst('getAuthorId', context);
-  if (!authorId) authorId = await getAuthor4Token(context.dbKey);
-  return authorId;
-};
-
-/**
- * Returns the AuthorID for a token.
- *
- * @deprecated Use `getAuthorId` instead.
- * @param {String} token The token
- */
-exports.getAuthor4Token = async (token) => {
-  warnDeprecated(
-      'AuthorManager.getAuthor4Token() is deprecated; use AuthorManager.getAuthorId() instead');
-  return await getAuthor4Token(token);
-};
-
-/**
- * Returns the AuthorID for a mapper.
- * @param {String} token The mapper
- * @param {String} name The name of the author (optional)
- */
-exports.createAuthorIfNotExistsFor = async (authorMapper, name) => {
-  const author = await mapAuthorWithDBKey('mapper2author', authorMapper);
-
-  if (name) {
-    // set the name of this author
-    await exports.setAuthorName(author.authorID, name);
-  }
-
-  return author;
-};
 
 /**
  * Returns the AuthorID for a mapper. We can map using a mapperkey,
@@ -174,6 +137,60 @@ const mapAuthorWithDBKey = async (mapperkey, mapper) => {
   return {authorID: author};
 };
 
+/**
+ * Returns the AuthorID for a token.
+ * @param {String} token The token of the author
+ * @return {Promise<string|*|{authorID: string}|{authorID: *}>}
+ */
+const getAuthor4Token = async (token) => {
+  const author = await mapAuthorWithDBKey('token2author', token);
+
+  // return only the sub value authorID
+  return author ? author.authorID : author;
+};
+
+/**
+ * Returns the AuthorID for a token.
+ * @param {String} token
+ * @param {Object} user
+ * @return {Promise<*>}
+ */
+exports.getAuthorId = async (token, user) => {
+  const context = {dbKey: token, token, user};
+  let [authorId] = await hooks.aCallFirst('getAuthorId', context);
+  if (!authorId) authorId = await getAuthor4Token(context.dbKey);
+  return authorId;
+};
+
+/**
+ * Returns the AuthorID for a token.
+ *
+ * @deprecated Use `getAuthorId` instead.
+ * @param {String} token The token
+ */
+exports.getAuthor4Token = async (token) => {
+  warnDeprecated(
+      'AuthorManager.getAuthor4Token() is deprecated; use AuthorManager.getAuthorId() instead');
+  return await getAuthor4Token(token);
+};
+
+/**
+ * Returns the AuthorID for a mapper.
+ * @param {String} authorMapper The mapper
+ * @param {String} name The name of the author (optional)
+ */
+exports.createAuthorIfNotExistsFor = async (authorMapper, name) => {
+  const author = await mapAuthorWithDBKey('mapper2author', authorMapper);
+
+  if (name) {
+    // set the name of this author
+    await exports.setAuthorName(author.authorID, name);
+  }
+
+  return author;
+};
+
+
 /**
  * Internal function that creates the database entry for an author
  * @param {String} name The name of the author
@@ -231,7 +248,7 @@ exports.setAuthorName = async (author, name) => await db.setSub(
 
 /**
  * Returns an array of all pads this author contributed to
- * @param {String} author The id of the author
+ * @param {String} authorID The id of the author
  */
 exports.listPadsOfAuthor = async (authorID) => {
   /* There are two other places where this array is manipulated:
@@ -255,7 +272,7 @@ exports.listPadsOfAuthor = async (authorID) => {
 
 /**
  * Adds a new pad to the list of contributions
- * @param {String} author The id of the author
+ * @param {String} authorID The id of the author
  * @param {String} padID The id of the pad the author contributes to
  */
 exports.addPad = async (authorID, padID) => {
@@ -282,7 +299,7 @@ exports.addPad = async (authorID, padID) => {
 
 /**
  * Removes a pad from the list of contributions
- * @param {String} author The id of the author
+ * @param {String} authorID The id of the author
  * @param {String} padID The id of the pad the author contributes to
  */
 exports.removePad = async (authorID, padID) => {
diff --git a/src/node/db/GroupManager.js b/src/node/db/GroupManager.js
index 4302048c4..2ab20ac16 100644
--- a/src/node/db/GroupManager.js
+++ b/src/node/db/GroupManager.js
@@ -25,6 +25,10 @@ const db = require('./DB');
 const padManager = require('./PadManager');
 const sessionManager = require('./SessionManager');
 
+/**
+ * Lists all groups
+ * @return {Promise<{groupIDs: string[]}>} The ids of all groups
+ */
 exports.listAllGroups = async () => {
   let groups = await db.get('groups');
   groups = groups || {};
@@ -33,6 +37,11 @@ exports.listAllGroups = async () => {
   return {groupIDs};
 };
 
+/**
+ * Deletes a group and all associated pads
+ * @param {String} groupID The id of the group
+ * @return {Promise<void>} Resolves when the group is deleted
+ */
 exports.deleteGroup = async (groupID) => {
   const group = await db.get(`group:${groupID}`);
 
@@ -68,6 +77,11 @@ exports.deleteGroup = async (groupID) => {
   await db.remove(`group:${groupID}`);
 };
 
+/**
+ * Checks if a group exists
+ * @param {String} groupID the id of the group to delete
+ * @return {Promise<boolean>} Resolves to true if the group exists
+ */
 exports.doesGroupExist = async (groupID) => {
   // try to get the group entry
   const group = await db.get(`group:${groupID}`);
@@ -75,6 +89,10 @@ exports.doesGroupExist = async (groupID) => {
   return (group != null);
 };
 
+/**
+ * Creates a new group
+ * @return {Promise<{groupID: string}>} the id of the new group
+ */
 exports.createGroup = async () => {
   const groupID = `g.${randomString(16)}`;
   await db.set(`group:${groupID}`, {pads: {}, mappings: {}});
@@ -85,6 +103,11 @@ exports.createGroup = async () => {
   return {groupID};
 };
 
+/**
+ * Creates a new group if it does not exist already and returns the group ID
+ * @param groupMapper the mapper of the group
+ * @return {Promise<{groupID: string}|{groupID: *}>} a promise that resolves to the group ID
+ */
 exports.createGroupIfNotExistsFor = async (groupMapper) => {
   if (typeof groupMapper !== 'string') {
     throw new CustomError('groupMapper is not a string', 'apierror');
@@ -103,6 +126,14 @@ exports.createGroupIfNotExistsFor = async (groupMapper) => {
   return result;
 };
 
+/**
+ * Creates a group pad
+ * @param {String} groupID The id of the group
+ * @param {String} padName The name of the pad
+ * @param {String} text The text of the pad
+ * @param {String} authorId The id of the author
+ * @return {Promise<{padID: string}>} a promise that resolves to the id of the new pad
+ */
 exports.createGroupPad = async (groupID, padName, text, authorId = '') => {
   // create the padID
   const padID = `${groupID}$${padName}`;
@@ -131,6 +162,11 @@ exports.createGroupPad = async (groupID, padName, text, authorId = '') => {
   return {padID};
 };
 
+/**
+ * Lists all pads of a group
+ * @param {String} groupID The id of the group
+ * @return {Promise<{padIDs: string[]}>} a promise that resolves to the ids of all pads of the group
+ */
 exports.listPads = async (groupID) => {
   const exists = await exports.doesGroupExist(groupID);
 
diff --git a/src/node/db/Pad.js b/src/node/db/Pad.js
index 751da1ae5..884b420f0 100644
--- a/src/node/db/Pad.js
+++ b/src/node/db/Pad.js
@@ -25,7 +25,8 @@ const promises = require('../utils/promises');
 /**
  * Copied from the Etherpad source code. It converts Windows line breaks to Unix
  * line breaks and convert Tabs to spaces
- * @param txt
+ * @param {String} txt The text to clean
+ * @returns {String} The cleaned text
  */
 exports.cleanText = (txt) => txt.replace(/\r\n/g, '\n')
     .replace(/\r/g, '\n')
@@ -73,9 +74,16 @@ class Pad {
     return this.publicStatus;
   }
 
+  /**
+   * Appends a new revision
+   * @param {Object} aChangeset The changeset to append to the pad
+   * @param {String} authorId The id of the author
+   * @return {Promise<number|string>}
+   */
   async appendRevision(aChangeset, authorId = '') {
     const newAText = Changeset.applyToAText(aChangeset, this.atext, this.pool);
-    if (newAText.text === this.atext.text && newAText.attribs === this.atext.attribs && this.head !== -1) {
+    if (newAText.text === this.atext.text && newAText.attribs === this.atext.attribs &&
+        this.head !== -1) {
       return this.head;
     }
     Changeset.copyAText(newAText, this.atext);
@@ -158,6 +166,10 @@ class Pad {
     return await this.db.getSub(`pad:${this.id}:revs:${revNum}`, ['meta', 'atext']);
   }
 
+  /**
+   * Returns all authors that worked on this pad
+   * @return {[String]} The id of authors who contributed to this pad
+   */
   getAllAuthors() {
     const authorIds = [];
 
@@ -173,8 +185,7 @@ class Pad {
   async getInternalRevisionAText(targetRev) {
     const keyRev = this.getKeyRevisionNumber(targetRev);
     const headRev = this.getHeadRevisionNumber();
-    if (targetRev > headRev)
-      targetRev = headRev;
+    if (targetRev > headRev) targetRev = headRev;
     const [keyAText, changesets] = await Promise.all([
       this._getKeyRevisionAText(keyRev),
       Promise.all(
diff --git a/src/node/db/PadManager.js b/src/node/db/PadManager.js
index cdcb58176..7c4021541 100644
--- a/src/node/db/PadManager.js
+++ b/src/node/db/PadManager.js
@@ -59,6 +59,7 @@ const padList = new class {
 
   /**
    * Returns all pads in alphabetical order as array.
+   * @returns {Promise<string[]>} A promise that resolves to an array of pad IDs.
    */
   async getPads() {
     if (!this._loaded) {
diff --git a/src/node/db/ReadOnlyManager.js b/src/node/db/ReadOnlyManager.js
index 33ce2930a..b96dd3413 100644
--- a/src/node/db/ReadOnlyManager.js
+++ b/src/node/db/ReadOnlyManager.js
@@ -26,13 +26,15 @@ const randomString = require('../utils/randomstring');
 
 /**
  * checks if the id pattern matches a read-only pad id
- * @param {String} the pad's id
+ * @param {String} id the pad's id
+ * @return {Boolean} true if the id is readonly
  */
 exports.isReadOnlyId = (id) => id.startsWith('r.');
 
 /**
  * returns a read only id for a pad
  * @param {String} padId the id of the pad
+ * @return {String} the read only id
  */
 exports.getReadOnlyId = async (padId) => {
   // check if there is a pad2readonly entry
@@ -53,12 +55,14 @@ exports.getReadOnlyId = async (padId) => {
 /**
  * returns the padId for a read only id
  * @param {String} readOnlyId read only id
+ * @return {String} the padId
  */
 exports.getPadId = async (readOnlyId) => await db.get(`readonly2pad:${readOnlyId}`);
 
 /**
  * returns the padId and readonlyPadId in an object for any id
- * @param {String} padIdOrReadonlyPadId read only id or real pad id
+ * @param {String} id read only id or real pad id
+ * @return {Object} an object with the padId and readonlyPadId
  */
 exports.getIds = async (id) => {
   const readonly = exports.isReadOnlyId(id);
diff --git a/src/node/db/SecurityManager.js b/src/node/db/SecurityManager.js
index 280c753bb..0e5b2c77c 100644
--- a/src/node/db/SecurityManager.js
+++ b/src/node/db/SecurityManager.js
@@ -49,6 +49,11 @@ const DENY = Object.freeze({accessStatus: 'deny'});
  *
  * WARNING: Tokens and session IDs MUST be kept secret, otherwise users will be able to impersonate
  * each other (which might allow them to gain privileges).
+ * @param {String} padID
+ * @param {String} sessionCookie
+ * @param {String} token
+ * @param {Object} userSettings
+ * @return {DENY|{accessStatus: String, authorID: String}}
  */
 exports.checkAccess = async (padID, sessionCookie, token, userSettings) => {
   if (!padID) {
diff --git a/src/node/db/SessionManager.js b/src/node/db/SessionManager.js
index 5ef75acfa..3d39ed747 100644
--- a/src/node/db/SessionManager.js
+++ b/src/node/db/SessionManager.js
@@ -81,6 +81,11 @@ exports.findAuthorID = async (groupID, sessionCookie) => {
   return sessionInfo.authorID;
 };
 
+/**
+ * Checks if a session exists
+ * @param {String} sessionID The id of the session
+ * @return {Promise<boolean>} Resolves to true if the session exists
+ */
 exports.doesSessionExist = async (sessionID) => {
   // check if the database entry of this session exists
   const session = await db.get(`session:${sessionID}`);
@@ -89,6 +94,10 @@ exports.doesSessionExist = async (sessionID) => {
 
 /**
  * Creates a new session between an author and a group
+ * @param {String} groupID The id of the group
+ * @param {String} authorID The id of the author
+ * @param {Number} validUntil The unix timestamp when the session should expire
+ * @return {Promise<{sessionID: string}>} the id of the new session
  */
 exports.createSession = async (groupID, authorID, validUntil) => {
   // check if the group exists
@@ -146,6 +155,11 @@ exports.createSession = async (groupID, authorID, validUntil) => {
   return {sessionID};
 };
 
+/**
+ * Returns the sessioninfos for a session
+ * @param {String} sessionID The id of the session
+ * @return {Promise<Object>} the sessioninfos
+ */
 exports.getSessionInfo = async (sessionID) => {
   // check if the database entry of this session exists
   const session = await db.get(`session:${sessionID}`);
@@ -161,6 +175,8 @@ exports.getSessionInfo = async (sessionID) => {
 
 /**
  * Deletes a session
+ * @param {String} sessionID The id of the session
+ * @return {Promise<void>} Resolves when the session is deleted
  */
 exports.deleteSession = async (sessionID) => {
   // ensure that the session exists
@@ -186,6 +202,11 @@ exports.deleteSession = async (sessionID) => {
   await db.remove(`session:${sessionID}`);
 };
 
+/**
+ * Returns an array of all sessions of a group
+ * @param {String} groupID The id of the group
+ * @return {Promise<Object>} The sessioninfos of all sessions of this group
+ */
 exports.listSessionsOfGroup = async (groupID) => {
   // check that the group exists
   const exists = await groupManager.doesGroupExist(groupID);
@@ -197,6 +218,11 @@ exports.listSessionsOfGroup = async (groupID) => {
   return sessions;
 };
 
+/**
+ * Returns an array of all sessions of an author
+ * @param {String} authorID The id of the author
+ * @return {Promise<Object>} The sessioninfos of all sessions of this author
+ */
 exports.listSessionsOfAuthor = async (authorID) => {
   // check that the author exists
   const exists = await authorManager.doesAuthorExist(authorID);
@@ -204,12 +230,16 @@ exports.listSessionsOfAuthor = async (authorID) => {
     throw new CustomError('authorID does not exist', 'apierror');
   }
 
-  const sessions = await listSessionsWithDBKey(`author2sessions:${authorID}`);
-  return sessions;
+  return await listSessionsWithDBKey(`author2sessions:${authorID}`);
 };
 
 // this function is basically the code listSessionsOfAuthor and listSessionsOfGroup has in common
 // required to return null rather than an empty object if there are none
+/**
+ * Returns an array of all sessions of a group
+ * @param {String} dbkey The db key to use to get the sessions
+ * @return {Promise<*>}
+ */
 const listSessionsWithDBKey = async (dbkey) => {
   // get the group2sessions entry
   const sessionObject = await db.get(dbkey);
@@ -218,8 +248,7 @@ const listSessionsWithDBKey = async (dbkey) => {
   // iterate through the sessions and get the sessioninfos
   for (const sessionID of Object.keys(sessions || {})) {
     try {
-      const sessionInfo = await exports.getSessionInfo(sessionID);
-      sessions[sessionID] = sessionInfo;
+      sessions[sessionID] = await exports.getSessionInfo(sessionID);
     } catch (err) {
       if (err.name === 'apierror') {
         console.warn(`Found bad session ${sessionID} in ${dbkey}`);
@@ -233,5 +262,9 @@ const listSessionsWithDBKey = async (dbkey) => {
   return sessions;
 };
 
-// checks if a number is an int
+/**
+ * checks if a number is an int
+ * @param {number|string} value
+ * @return {boolean} If the value is an integer
+ */
 const isInt = (value) => (parseFloat(value) === parseInt(value)) && !isNaN(value);
diff --git a/src/node/handler/APIHandler.js b/src/node/handler/APIHandler.js
index 2c060c239..3b5a3fb63 100644
--- a/src/node/handler/APIHandler.js
+++ b/src/node/handler/APIHandler.js
@@ -165,12 +165,13 @@ exports.version = version;
 
 /**
  * Handles a HTTP API call
- * @param functionName the name of the called function
+ * @param {String} apiVersion the version of the api
+ * @param {String} functionName the name of the called function
  * @param fields the params of the called function
  * @req express request object
  * @res express response object
  */
-exports.handle = async function (apiVersion, functionName, fields, req, res) {
+exports.handle = async function (apiVersion, functionName, fields) {
   // say goodbye if this is an unknown API version
   if (!(apiVersion in version)) {
     throw new createHTTPError.NotFound('no such api version');
diff --git a/src/node/handler/ExportHandler.js b/src/node/handler/ExportHandler.js
index 417380866..e0a89e6d0 100644
--- a/src/node/handler/ExportHandler.js
+++ b/src/node/handler/ExportHandler.js
@@ -38,6 +38,11 @@ const tempDirectory = os.tmpdir();
 
 /**
  * do a requested export
+ * @param {Object} req the request object
+ * @param {Object} res the response object
+ * @param {String} padId the pad id to export
+ * @param {String} readOnlyId the read only id of the pad to export
+ * @param {String} type the type to export
  */
 exports.doExport = async (req, res, padId, readOnlyId, type) => {
   // avoid naming the read-only file as the original pad's id
diff --git a/src/node/handler/ImportHandler.js b/src/node/handler/ImportHandler.js
index 5dfc152c5..6caf7ba93 100644
--- a/src/node/handler/ImportHandler.js
+++ b/src/node/handler/ImportHandler.js
@@ -73,6 +73,10 @@ const tmpDirectory = os.tmpdir();
 
 /**
  * do a requested import
+ * @param {Object} req the request object
+ * @param {Object} res the response object
+ * @param {String} padId the pad id to export
+ * @param {String} authorId the author id to use for the import
  */
 const doImport = async (req, res, padId, authorId) => {
   // pipe to a file
@@ -233,6 +237,14 @@ const doImport = async (req, res, padId, authorId) => {
   return false;
 };
 
+/**
+ * Handles the request to import a file
+ * @param {Request} req the request object
+ * @param {Response} res the response object
+ * @param {String} padId the pad id to export
+ * @param {String} authorId the author id to use for the import
+ * @return {Promise<void>} a promise
+ */
 exports.doImport = async (req, res, padId, authorId = '') => {
   let httpStatus = 200;
   let code = 0;
diff --git a/src/node/handler/SocketIORouter.js b/src/node/handler/SocketIORouter.js
index 863401ace..d9e76158d 100644
--- a/src/node/handler/SocketIORouter.js
+++ b/src/node/handler/SocketIORouter.js
@@ -35,8 +35,9 @@ const components = {};
 
 let io;
 
-/**
- * adds a component
+/** adds a component
+ * @param {string} moduleName
+ * @param {Module} module
  */
 exports.addComponent = (moduleName, module) => {
   if (module == null) return exports.deleteComponent(moduleName);
@@ -44,10 +45,15 @@ exports.addComponent = (moduleName, module) => {
   module.setSocketIO(io);
 };
 
+/**
+ * removes a component
+ * @param {Module} moduleName
+ */
 exports.deleteComponent = (moduleName) => { delete components[moduleName]; };
 
 /**
  * sets the socket.io and adds event functions for routing
+ * @param {Object} _io the socket.io instance
  */
 exports.setSocketIO = (_io) => {
   io = _io;
diff --git a/src/node/hooks/express/admin.js b/src/node/hooks/express/admin.js
index 763698332..ed272efd8 100644
--- a/src/node/hooks/express/admin.js
+++ b/src/node/hooks/express/admin.js
@@ -1,6 +1,14 @@
 'use strict';
 const eejs = require('../../eejs');
 
+
+/**
+ * Add the admin navigation link
+ * @param hookName {String} the name of the hook
+ * @param args {Object} the object containing the arguments
+ * @param {Function} cb  the callback function
+ * @return {*}
+ */
 exports.expressCreateServer = (hookName, args, cb) => {
   args.app.get('/admin', (req, res) => {
     if ('/' !== req.path[req.path.length - 1]) return res.redirect('./admin/');
diff --git a/src/node/hooks/express/adminplugins.js b/src/node/hooks/express/adminplugins.js
index 543f04c0f..19908cf59 100644
--- a/src/node/hooks/express/adminplugins.js
+++ b/src/node/hooks/express/adminplugins.js
@@ -121,6 +121,13 @@ exports.socketio = (hookName, args, cb) => {
   return cb();
 };
 
+/**
+ * Sorts  a list of plugins by a property
+ * @param {Object} plugins The plugins to sort
+ * @param {Object} property The property to sort by
+ * @param  {String} dir The directory of the plugin
+ * @return {Object[]}
+ */
 const sortPluginList = (plugins, property, /* ASC?*/dir) => plugins.sort((a, b) => {
   if (a[property] < b[property]) {
     return dir ? -1 : 1;
diff --git a/src/node/hooks/express/openapi.js b/src/node/hooks/express/openapi.js
index 240b6fcf5..69f268256 100644
--- a/src/node/hooks/express/openapi.js
+++ b/src/node/hooks/express/openapi.js
@@ -696,10 +696,20 @@ exports.expressPreSession = async (hookName, {app}) => {
   }
 };
 
-// helper to get api root
+/**
+ * Helper to get the current root path for an API version
+ * @param {String} version The API version
+ * @param {APIPathStyle} style The style of the API path
+ * @return {String} The root path for the API version
+ */
 const getApiRootForVersion = (version, style = APIPathStyle.FLAT) => `/${style}/${version}`;
 
-// helper to generate an OpenAPI server object when serving definitions
+/**
+ * Helper to generate an OpenAPI server object when serving definitions
+ * @param {String} apiRoot The root path for the API version
+ * @param {Request} req The express request object
+ * @return {url: String} The server object for the OpenAPI definition location
+ */
 const generateServerForApiVersion = (apiRoot, req) => ({
   url: `${settings.ssl ? 'https' : 'http'}://${req.headers.host}${apiRoot}`,
 });
diff --git a/src/node/security/crypto.js b/src/node/security/crypto.js
index ebe918509..9cf0a95a0 100644
--- a/src/node/security/crypto.js
+++ b/src/node/security/crypto.js
@@ -12,4 +12,4 @@ exports.hkdf = util.promisify(crypto.hkdf);
 /**
  * Promisified version of Node.js's crypto.randomBytes
  */
-exports.randomBytes = util.promisify(crypto.randomBytes);
\ No newline at end of file
+exports.randomBytes = util.promisify(crypto.randomBytes);