diff --git a/back/mails/imap/ImapInstance.ts b/back/mails/imap/ImapInstance.ts
index 3248ef6..064307e 100644
--- a/back/mails/imap/ImapInstance.ts
+++ b/back/mails/imap/ImapInstance.ts
@@ -3,12 +3,12 @@ import { Account } from "./ImapSync";
 import Imap from "imap";
 import { getAllMailboxes, registerMailbox } from "../../db/imap/imap-db";
 import logger from "../../system/Logger";
-import Box from "./Box";
+import Mailbox from "./Mailbox";
 
 export class ImapInstance {
     imap: Imap;
     account: Account;
-    boxes: Box[];
+    boxes: Mailbox[];
 
     constructor(account) {
         this.imap = new Imap({
@@ -44,13 +44,13 @@ export class ImapInstance {
     imapReady() {
         getAllMailboxes(this.account.id).then((mailboxes) => {
             if (mailboxes.length > 0) {
-                this.boxes.push(new Box(this.imap, mailboxes[0].mailbox_id, mailboxes[0].mailbox_name));
+                this.boxes.push(new Mailbox(this.imap, mailboxes[0].mailbox_id, mailboxes[0].mailbox_name));
             } else {
                 this.imap.getBoxes("", (err, boxes) => {
                     if (err) logger.err(err);
                     const allBoxName = this.getAllBox(boxes);
                     registerMailbox(this.account.id, allBoxName).then((mailboxId) => {
-                        this.boxes.push(new Box(this.imap, mailboxId, allBoxName));
+                        this.boxes.push(new Mailbox(this.imap, mailboxId, allBoxName));
                     });
                 });
             }
diff --git a/back/mails/imap/Box.ts b/back/mails/imap/Mailbox.ts
similarity index 61%
rename from back/mails/imap/Box.ts
rename to back/mails/imap/Mailbox.ts
index cb04aa1..8106650 100644
--- a/back/mails/imap/Box.ts
+++ b/back/mails/imap/Mailbox.ts
@@ -1,47 +1,68 @@
-import Imap, { ImapMessageAttributes, MailBoxes } from "imap";
+import Imap, { ImapMessageAttributes, Box } from "imap";
 import { getMailbox, updateMailbox } from "../../db/imap/imap-db";
 import { Attrs, AttrsWithEnvelope } from "../../interfaces/mail/attrs.interface";
 import logger from "../../system/Logger";
 import RegisterMessageInApp from "../saveMessage";
 import { saveMessage } from "../storeMessage";
 
-export default class Box {
+export default class Mailbox {
     imap: Imap;
     boxName: string;
     id: number;
-    box: MailBoxes;
+    box: Box;
+    msgToSync: number;
+    syncing: boolean;
 
     constructor(_imap, _boxId, _boxName) {
         this.imap = _imap;
         this.boxName = _boxName;
         this.id = _boxId;
         this.box;
+        this.msgToSync = 0;
+        this.syncing = false;
         this.init();
     }
 
     async init() {
+        // get mailbox from the database
         this.box = (await getMailbox(this.id))[0];
 
         const readOnly = true;
         this.imap.openBox(this.boxName, readOnly, (err, box) => {
             if (err) logger.err(err);
-            this.sync(this.box.uidnext, box.uidnext);
+
+            // sync only if has new messages
+            if (this.box.uidnext < box.uidnext) {
+                this.sync(this.box.uidnext, box.uidnext);
+            } else {
+                logger.log("Already up to date")
+            }
+
+            this.imap.on("mail", (numNewMsgs: number) => {
+                if (!this.syncing) {
+                    // if not syncing restart a sync
+                    this.sync(this.box.uidnext, this.box.uidnext + numNewMsgs);
+                } else {
+                    // else save number of message to sync latter
+                    this.msgToSync += numNewMsgs;
+                }
+            });
         });
     }
 
-    sync(savedUid, currentUid) {
+    async sync(savedUid: number, currentUid: number) {
+        this.syncing = true;
         const promises: Promise<unknown>[] = [];
         const mails: Attrs[] = [];
         logger.log(`Syncing from ${savedUid} to ${currentUid} uid`);
         const f = this.imap.seq.fetch(`${savedUid}:${currentUid}`, {
-        // const f = this.imap.seq.fetch(`${savedUid}:${currentUid}`, {
             size: true,
             envelope: true,
         });
 
         f.on("message", (msg, seqno) => {
             msg.once("attributes", (attrs: AttrsWithEnvelope) => {
-                console.log(attrs.envelope)
+                console.log(attrs.envelope);
                 mails.push(attrs);
                 promises.push(saveMessage(attrs, this.id, this.imap));
             });
@@ -53,7 +74,6 @@ export default class Box {
 
         f.once("end", async () => {
             let step = 20;
-            logger.log(promises.length)
             for (let i = 0; i < promises.length; i += step) {
                 for (let j = i; j < (i + step && promises.length); j++) {
                     await new Promise((resolve, reject) => {
@@ -72,6 +92,16 @@ export default class Box {
                 updateMailbox(this.id, mails[i].uid);
             }
             updateMailbox(this.id, currentUid);
+            this.syncing = false;
+
+            // if has receive new msg during last sync then start a new sync
+            if (this.msgToSync > 0) {
+                const currentUid = this.box.uidnext;
+                this.box.uidnext += this.msgToSync;
+                // reset value to allow to detect new incoming message while syncing
+                this.msgToSync = 0;
+                this.sync(currentUid, this.box.uidnext);
+            }
         });
     }
-}
\ No newline at end of file
+}