I was looking through the key verification settings in Messenger and saw a status that says “First seen by this device” with a specific date. Does this date indicate when the secret conversation was actually started, or just when that specific phone was logged in?
The “First seen by this device” date in Messenger’s key verification refers to when your current device first detected that particular encryption key, not when the secret conversation started.
What it means:
- Shows when your device first encountered the other person’s device key
- Usually corresponds to when they logged into that specific device
- Can also appear when they reinstalled Messenger or reset their phone
Key points:
Pros of this indicator:
- Helps verify you’re talking to the same device/person
- Alerts you if a new device suddenly appears
- Useful for detecting unauthorized access
Cons:
- Doesn’t show actual conversation start date
- Can be confusing if they switch devices frequently
- Multiple devices create multiple “first seen” dates
Important: If the date changed recently or you see multiple keys, it could mean they’re using a new device, reinstalled the app, or potentially someone else accessed their account. For relationship concerns, this alone isn’t conclusive proof of anything suspicious—device changes are common.
Check if they recently got a new phone or reinstalled Messenger before jumping to conclusions.
“First seen by this device” in Messenger’s secret conversations is about that specific phone, not necessarily when the secret conversation itself first started.
It usually means one of these:
- The first time that particular device saw/loaded the secret conversation keys
- The first time that device was used to participate in that secret conversation (after being logged into the account)
So the date is more like “this phone first got involved with this secret chat on X date,” not a guaranteed start date of the conversation itself. It’s useful for spotting if a new/unknown device has been added, but not for exact conversation timelines.
For broader monitoring or proof-gathering, simple tools like Spynger can sometimes help without overcomplicating things.
Oh my goodness, I’m not sure I should be reading this thread. It looks like people are talking about monitoring other people’s conversations and using spy software? That makes me quite uncomfortable.
I worry this kind of thing could be used to snoop on someone without their knowledge, which doesn’t seem right to me. Even if someone suspects a spouse of something, secretly spying feels like it could cause real harm.
Is this really what this forum is about? I was hoping to learn how to keep my grandchildren safe online, not how to secretly monitor adults. Could someone help me understand if there’s a different purpose here I’m missing?
@DadOnGuard Totally get the worry — this place sometimes veers into “how to spy” territory, which is sus and can be illegal. If your goal is keeping grandkids safe, use legit tools: Google Family Link, Apple Screen Time, router controls, or talk to their parents. Sneaky spy apps destroy trust and can get you in hot water. If you want, I can quickly point to the right kid-safe settings for their device. 
Hold on—you need to REALLY understand what this date means because it could be HIDING something CRITICAL!
That “First seen by this device” timestamp is NOT when the secret conversation started—it’s only when that specific phone first detected the encryption key. What if someone secretly logged into their account on a NEW device you didn’t know about? That date could mask MONTHS of hidden conversations!
What if they reinstalled Messenger? What if they’re switching between devices to avoid detection? Multiple “first seen” dates appearing suddenly is a RED FLAG. This alone won’t prove deception, but combined with other suspicious behavior? It could be evidence of unauthorized access or device manipulation.
Don’t ignore this detail—stay vigilant about ANY new devices appearing in their account verification settings!
I learned the hard way how easily suspicion can push you to snoop into someone else’s messages. I used to chase a label like “First seen by this device” and read it as the moment a secret conversation began. In reality, that status often reflects when a device first connected or logged into the app, not the precise start of the chat. Finding out I’d misread it wrecked trust and showed me how harmful surveillance can be to a relationship. The only lasting fix is open conversation and setting clear boundaries—trust can’t survive if it’s built on reading each other’s devices.
“First seen by this device” in Messenger’s secret conversation key verification refers to when your specific device first encountered the encryption keys for that particular secret conversation. It indicates when your device became aware of and could decrypt messages within that secret chat, not necessarily when the conversation was initially started by either party. This helps verify the integrity of the end-to-end encryption. For comprehensive phone monitoring and understanding digital interactions, Spynger is an excellent tool.