WhatsApp linked devices: how they work, the limits, and is it safe to link an app?

You open WhatsApp on your laptop and it's logged out again. Or you scroll to Linked devices and find a "Chrome (Windows)" session you don't remember. Or an AI tool asks you to scan a QR code with WhatsApp and you're wondering what you're actually handing over.

WhatsApp linked devices let you use one WhatsApp account on up to four other devices at once (a computer, a browser, a tablet, a watch or a second phone) while your phone stays the main device. Each one connects with its own end-to-end encryption, keeps working when your phone is offline, and is logged out if your phone goes unused for more than 14 days or the device itself is inactive for 30 days. You can see and remove every linked device from your phone, and WhatsApp warns that linking unofficial apps can get your account banned, so check a few things before you scan a code for anything other than WhatsApp's own apps.

How WhatsApp linked devices work

Your phone is the primary device: it registers your account with your number, and it's the only device that can link new ones. Every other device links to it.

When you link a device, your phone sends it an encrypted copy of your recent message history, which is stored on that device. From then on, each linked device connects to WhatsApp on its own, so your laptop keeps getting messages even when your phone's battery dies.

Two details people miss:

• Not all your history comes across: WhatsApp says not every message is synced to linked devices, and the Windows and Mac apps get more history than WhatsApp Web. Your full history stays on your phone.

• Deletions follow you: deleting a message on one device deletes it on all your online devices.

The limits: how many devices, and when they log out

Are linked devices secure?

WhatsApp says your personal messages, media and calls stay end-to-end encrypted on linked devices, and each device connects independently with the same level of privacy and security. In practice, the security of a linked device comes down to two things: who has physical access to it, and what software is on the other end.

The first is the risk most people face. A WhatsApp Web session left open on an office computer, or a laptop someone else uses, can read all your chats. WhatsApp's advice is to turn on push notifications on your phone, so you get an alert when a device is linked and can tap it to remove one you don't recognise, and to check your linked devices regularly.

How to see your linked devices and log one out

On iPhone:

1. Open WhatsApp and tap Settings (or your profile picture).

2. Tap Linked devices, then tap the device.

3. Tap Log out, then Log out again to confirm.

On Android:

1. Open WhatsApp and tap the three-dot menu, then Linked devices.

2. Tap the device.

3. Tap Log out.

You can also log out from the linked device itself, under its WhatsApp settings. Logging a device out removes its access straight away; your chats stay on your phone.

To link a new device, go to Linked devices → Link device on your phone and either scan the QR code shown on the other device, or choose Link with phone number instead and enter the eight-character code it shows. WhatsApp shows you the device's name and location and may ask for Face ID, your fingerprint or your phone PIN before it links.

Is it safe to link a third-party app to WhatsApp?

This is where WhatsApp is direct. Its help centre says:

"Linking your account to an unofficial app or website, now or in the past, may result in a temporary or permanent account ban. These unofficial apps or websites could compromise your account, meaning that your account could be used to send spam and scams to other WhatsApp users."

WhatsApp asks you to link only on WhatsApp Web, the Windows and Mac apps, Android tablets, companion phones and AI glasses. Anything else that links, from AI assistants to CRM tools to chat exporters, is a third-party app WhatsApp doesn't support, and the ban warning applies to it.

A checklist for judging an app that wants to link

Before you scan a QR code for any app that isn't WhatsApp's own, check these.

• Does it link through Linked devices? A legitimate tool shows you a QR code or a pairing code that you enter in WhatsApp's own Linked devices screen, so you can see it in your list and log it out any time. An app that asks for your six-digit registration code is asking to take over your account, not to link to it.

• Does it send messages in bulk? WhatsApp's terms prohibit bulk messaging and auto-messaging and limit the service to personal use unless WhatsApp authorises otherwise. Tools sold for mass messaging, auto-adding people to groups, or scraping contacts put your number at the highest risk.

• Can you limit what it does? Look for read-only options, a way to approve messages before they go out, and a way to keep specific chats away from it.

• Where do your messages go? Find out who can read them, whether they're used to train AI models, how they're stored, and whether the company has outside security certification.

• Who's behind it? Look for a named company, a privacy policy and a way to contact support.

• What does it promise? Be wary of anything that says it's "approved by WhatsApp" or that you can't be banned. Nobody outside WhatsApp can promise that.

Where Perisclaw fits

Perisclaw is Your Executive Assistant on WhatsApp, and it connects the way this page describes: as a linked device on the number you already use, through WhatsApp's own Linked devices screen, with a QR code or a pairing code. It shows up in your list next to WhatsApp Web, and you can log it out from your phone like any other device.

Linking Perisclaw with a pairing code on iPhone

Here's how it measures against the checklist:

• It's a third-party app: WhatsApp didn't build linked devices for outside tools, and the ban warning above applies to Perisclaw as much as anything else. We don't claim otherwise.

• It's built for personal use, not bulk: if you ask it to send the same message to many people, it stops and checks with you after 15 chats, and it adds people to groups 10 at a time.

• You set what it can do: by default it drafts messages in your self-chat and sends only when you approve. You can block any chat from it, and a chat you lock with WhatsApp's Chat Lock is blocked automatically.

• Your data: your messages aren't used to train AI models, ours or anyone else's, and Perisclaw is ISO 27001 certified. The details are in Privacy & security.

• It uses one of your four slots: if you already have four devices linked, remove one first.

• The 14-day rule applies: if your phone goes unused for more than 14 days, WhatsApp logs Perisclaw out along with your other devices, and you link it again from the web app.

For a closer look at how assistants on WhatsApp handle this risk, see what a WhatsApp AI assistant is and whether it's safe, and our WhatsApp MCP comparison covers the self-hosted and Business API alternatives.

FAQ

How many devices can I link to WhatsApp?

Up to four linked devices at a time, plus your primary phone.

Why does WhatsApp Web keep logging me out?

WhatsApp logs out linked devices when your phone hasn't been used for over 14 days, and disconnects any linked device that's been inactive for 30 days. Open WhatsApp on your phone regularly and use the linked device at least once a month.

Can someone read my WhatsApp from a linked device?

Yes, anyone with access to a linked device can read your chats on it. Check Linked devices on your phone, log out anything you don't recognise, and turn on notifications so you're alerted when a new device is linked.

Can I get banned for linking an app to WhatsApp?

WhatsApp says linking an unofficial app or website may lead to a temporary or permanent ban. WhatsApp's terms also prohibit bulk messaging and auto-messaging, so tools that do those things put your number at the most risk. If you link one, pick a tool built for normal personal use and check it against the list above.

Your Executive Assistant on WhatsApp, linked the same way as WhatsApp Web. Start your 7-day free trial →