What a fingerprint reader actually solves

A biometric terminal ties an attendance event to a body part. That is a genuinely strong answer, and any honest discussion of alternatives has to start by saying so.

What it does not solve is everything around it: the queue at shift change, the enrolment session for every new starter, the reader that will not recognise a wet or worn fingertip, and a second purchase for every site you open. For a single site with a stable team those costs are bearable. They scale badly.

Three checks that make proxy clock-ins harder

A phone-based system cannot verify a body. It can verify the circumstances of the request, and stacking those checks is what closes most of the practical gap.

  • Registered device: the clock-in must come from the phone bound to that employee’s company membership. A colleague clocking in for someone else would have to be holding their phone.
  • Point-of-action location: the request is checked against the workplace’s coordinates and radius at the moment it is made, with the accuracy of the reading treated as part of the answer.
  • Workplace network: the request is checked against the network the site expects, which often works better indoors than a satellite fix.

Why the device check does most of the work

Location alone is weak against buddy punching, because a colleague who is genuinely at work is genuinely at the workplace. A geofence cannot tell you whose finger pressed the button.

Requiring the registered device changes the question from "is this request coming from the workplace" to "is it coming from this employee’s known phone". To clock in for an absent colleague, someone now has to physically have that colleague’s unlocked phone — a much higher bar than borrowing a badge, and one most teams will not cross casually.

In SlidesClock the device identifiers are recorded for verification. Hardware-level cryptographic attestation is not operational, so this is a strong practical signal rather than a cryptographic guarantee, and it is worth saying that plainly.

What this approach cannot claim

It is not biometric identification. A determined pair of employees who hand over a phone can still defeat it, exactly as a determined pair can defeat a badge system.

GPS and network checks are probabilistic signals, not proof of presence. No combination of them makes attendance unfalsifiable, and software that says otherwise is overselling.

If a regulation in your industry specifically requires biometric identification, a terminal remains the correct answer. The honest claim for a phone-based system is that it raises the cost of a proxy clock-in enough that it stops being casual — which, for most businesses, is the actual goal.

The part that is not technical

Buddy punching is usually a symptom. Teams that do it tend to be covering for a colleague who is five minutes late under a policy with no grace period, or clocking in a shift that was communicated badly.

A configurable grace period and a schedule everybody can see in the app remove a surprising amount of the motive. So does a correction workflow: if a genuinely late arrival can be explained and reviewed rather than silently punished, there is far less reason to arrange a cover-up.

A sensible configuration

For a site where proxy clock-ins are the main worry, require the registered device and one workplace signal — location outdoors, the workplace network indoors. Set a grace period that reflects how people actually arrive, and keep corrections available so an honest mistake has an honest route.

All of that is configurable per workplace, so a warehouse and a head office do not have to share one rule. You can test the arrangement on the free plan before committing a budget to it.