How to Use Blackbird with Mercer Mettl
Mercer Mettl runs most large campus and corporate assessments in India, usually through its Mettl Secure Browser.
What Mercer Mettl monitors
- —Mettl Secure Browser kiosk lockdown
- —Webcam image capture at intervals plus AI review
- —Tab-switch and window-focus counters
- —Multiple-face and no-face detection
- —Audio monitoring for conversation
How Blackbird fits in
Mettl's flagging is dominated by two signals: focus changes away from the assessment window and webcam anomalies like a second face or a missing candidate. Both are behavioural.
Blackbird is a lightweight native Windows overlay drawn at the system compositor level. It is not a browser tab, an Electron window, or a shared surface, so it does not show up in screen recordings, screen-share streams, or active-window checks. It stays on top, accepts clicks without stealing focus, and disappears instantly with a hotkey. Clicking the overlay does not change the focused window, so Mettl's tab-switch counter stays at zero.
Practical tips
- +Never alt-tab; use the overlay instead.
- +Keep your face centred and lit — no-face events are the most common flag.
- +Stay silent; Mettl records audio.
- +Write code in your own style rather than pasting a full solution.
Frequently asked questions
Does Mettl Secure Browser detect Blackbird?
The secure browser enforces kiosk mode and blocks known applications. Blackbird is a native overlay drawn above it and is not one of the applications it checks for.
Will it increase my tab-switch count?
No. The overlay never takes focus.
Does it work for coding rounds?
Yes. Screenshot the problem, get the approach, then type it yourself.
Is the free tier enough for a Mettl test?
The free tier caps sessions at 15 minutes. Most Mettl assessments run longer, so Pro or the one-time $20 month is the practical choice.
You are responsible for following the rules of any exam, employer or institution you use Blackbird with. No tool can account for human observation or behavioural review.