Is someone reading your messages? How to check linked devices and sessions

The quickest way to find out is to look at the devices signed in to your accounts: WhatsApp, Telegram, Instagram and Apple each keep a list of every phone, computer and browser that can see your messages, and each lets you log out one you don’t recognize in a few taps. If everything on those lists is yours, nobody is reading along through a signed-in device.

This guide walks through each list, a few settings on your Mac, and what to do, calmly, if you find something unfamiliar. Every step comes from WhatsApp’s, Telegram’s, Instagram’s and Apple’s own help pages, which we checked on 20 October 2026 and link below. Menu names can change between app versions.

A note on safety first. If you think someone you live with or are close to is watching your messages, they may notice when a device is logged out. Apple’s advice applies to every app: “Before making changes or deleting information, consider potential impacts to your safety and privacy” (Apple). There’s more on this at the end.

Where each app lists the devices signed in to your account (checked October 2026)

App	Where to look	What it shows	How to remove a device
WhatsApp	On your phone: Settings → Linked devices	Computers, browsers, tablets and companion phones linked to your account	Tap the device, then Log out
Telegram	Settings → Devices, or Privacy and Security → Active Sessions on a Mac	Every app and browser signed in	Terminate that session, or all other sessions
Instagram	Accounts Center → Password and security → Where you’re logged in	Devices signed in to your account	Select devices to log out
iMessage (Apple)	iPhone: Settings → [your name]; Mac: System Settings → [your name]; web: account.apple.com	Devices signed in with your Apple Account	Remove from Account

Can someone read my WhatsApp messages from another phone?

Only if another device is linked to your account, or someone has your phone itself. WhatsApp lets up to four devices link to one account, including computers, browsers, tablets and companion phones, and every one of them is listed on your main phone (WhatsApp Help Center).

To check:

1. Open WhatsApp on your phone and go to Settings (on some versions you tap your profile picture first).
2. Tap Linked devices to see every device linked to your account.
3. If you don’t recognize one, tap it, then tap Log out.

A few things WhatsApp does for you: with push notifications on, your phone gets a notification when a new device is linked so you can review or remove it; it logs out a linked device that’s been inactive for 30 days, and it logs out all linked devices if your phone isn’t used for more than 14 days (WhatsApp Help Center). Linking a new device is done from your phone, which is why your phone’s own passcode matters.

Then turn on two-step verification, which adds a password that’s needed when your number is registered on a phone again. On iPhone it’s under You → Account → Two-step verification (WhatsApp Help Center).

Telegram: Devices and Active Sessions

Telegram lists every app and browser signed in to your account. Telegram’s FAQ says to “go to Settings > Devices (or Privacy & Security > Active Sessions)” and end any session you don’t want (Telegram FAQ).

1. Open Settings → Devices on your phone. On a Mac, look for Devices in Settings, or Active Sessions under Privacy and Security.
2. Tap or click a session you don’t recognize and terminate it, or choose Terminate all other sessions, which logs out every device except the one you’re holding.
3. Turn on Two-Step Verification in Privacy and Security. With it on, Telegram’s FAQ says you need both an SMS code and a password to log in.

You can also set Telegram to log out devices automatically after a period of inactivity, from the same Devices screen (Telegram).

Instagram: Where you’re logged in

Instagram’s list lives in Accounts Center. On a computer at instagram.com (Instagram Help Center):

1. Click More in the bottom left, then Settings.
2. Click Accounts Center, then Password and security, then Where you’re logged in.
3. Choose your account to see each device.
4. Click Select devices to log out, tick the ones you don’t recognize, and click Log out.

If you see Login activity instead, you can mark each login “This was me” or “This wasn’t me”; choosing the second takes you through changing your password. Instagram says it’s moving some people to Meta account settings, so the names may differ slightly.

iMessage: devices on your Apple Account

iMessage doesn’t have a separate “linked devices” list. Any iPhone, iPad or Mac signed in to your Apple Account can get your iMessages, so the list to check is your Apple Account’s devices (Apple):

• iPhone or iPad: open Settings, tap your name, and scroll down to the list of devices.
• Mac: open System Settings and click your name.
• On the web: sign in at account.apple.com and choose Devices.

Select a device you don’t recognize and choose Remove from Account. A removed device can no longer use iCloud or Find My and stops showing your two-factor codes, but Apple notes it may reappear the next time it connects to the internet if it’s still signed in. If it isn’t yours, change your Apple Account password too.

Two more checks on iPhone:

• Text Message Forwarding (Settings → Apps → Messages → Text Message Forwarding) lists the other devices that can send and receive the SMS, MMS and RCS texts from your iPhone (Apple).
• Safety Check (Settings → Privacy & Security → Safety Check, iOS 16 or later) walks you through the people, apps and devices that have access to your information. Manage Sharing & Access lets you review one item at a time; Emergency Reset stops sharing with everyone at once (Apple).

On your Mac: check app permissions

Signed-in devices aren’t the only way in. On a Mac, an app you’ve given certain permissions can read your messages without signing in to anything. Open System Settings → Privacy & Security and look at these three lists (Apple):

• Full Disk Access: apps here can read data from other apps, including Messages and Mail. Our guide to Full Disk Access explains why some legitimate apps need it.
• Accessibility: apps here can control your Mac.
• Screen & System Audio Recording: apps here can see what’s on your screen.

Turn off anything you don’t recognize or no longer use. If you’re not sure what an app is, look it up before you remove it: plenty of legitimate apps (backup tools, password managers, screen-sharing apps) appear in these lists.

What about apps that combine your chats?

Apps that put several messaging services in one inbox sign in to your accounts too, so you can check and remove them the same way. Just don’t expect every list to show the app’s name: Telegram and Instagram don’t document what name a sign-in made through another app’s window shows.

Tera Chat for Mac, a free app made by the team behind this blog, is one of them, so here’s how it connects. WhatsApp pairs it as a linked device with a QR code, like WhatsApp Web, so it’s in Linked devices. Telegram sign-in happens on Telegram’s own website (web.telegram.org), in a separate browser window that Tera Chat opens. Instagram sign-in happens on Instagram’s own login page inside the app. iMessage isn’t a sign-in at all: Tera Chat reads your Messages history on your Mac, which needs Full Disk Access, and sends through the Messages app, which needs Automation, so it’s in those two lists instead. Your messages stay on your Mac and aren’t uploaded to a Tera Chat server; if you set up its AI features, the chats they work on go to the AI provider you use (with a Tera Chat AI plan, Anthropic’s Claude through Tera Chat’s server, which doesn’t keep them).

WhatsApp’s own linked-devices page also warns that linking unofficial apps or websites may put your account at risk and can lead to a temporary or permanent ban. We cover that trade-off in are all-in-one messaging apps safe? and Tera Chat’s own answers in is Tera Chat safe?. If AI is the worry, see is it safe to let AI read your messages?

If you find a device you don’t recognize

Take a breath: an unfamiliar entry isn’t always an intruder. Names can be generic (“Chrome”, “Mac OS”), an old phone you traded in may still be listed, and locations are often approximate. Then:

1. Check it’s not yours. Think about old phones, a work computer, a browser you used once, or an app you connected.
2. If you’re safe to do so, log it out from the list in the app, as above.
3. Change your password where there is one (Apple Account, Instagram), and turn on two-step verification for WhatsApp and Telegram.
4. Change your phone’s passcode if anyone else might know it. Apple’s personal safety checklist starts with exactly this, along with reviewing your devices and any Face ID or Touch ID you didn’t set up (Apple).
5. Look again in a few days to make sure it hasn’t come back.

If the device belongs to someone you know, and especially someone you’re in a relationship with, it may be safer to make a plan before you remove anything. In the US, the National Domestic Violence Hotline can help: call 800-799-7233 or text START to 88788 (The Hotline). If you’re in immediate danger, call 911 or your local emergency number. Outside the US, a local domestic abuse or victim support service can help in the same way.

For keeping chats private from people who use your Mac in person, see how to hide or lock chats on a Mac.