Vojo Harvester™
The glass doesn't lie.
An independent sensor watches the screen itself. That is Proof of Display: Tier 3 glass proof a playback log can never invent.
Buy it for the panels that need hard proof. Or let it deepen Passport and vTrust Score when it is already on the screen. No special setup.
Complete guide
Why trust a log when you can watch the glass?
Vojo Harvester™ produces Proof of Display: independent confirmation of what hit the panel. Still plain English.
Out of the box
You came for hard proof.
This is what hard proof looks like
Most DOOH “proof” stops at a software event. Harvester starts at the glass.
Proof from the glass, not the player
A log can say content was sent. Harvester says what actually appeared on the panel. Same way a person looking at the screen would know.
A metric you can sell on its own
Proof of Display is a named glass KPI. Fit Harvesters where buyers demand hard evidence. Premium inventory with a clear story.
Deepens Passport without a rebuild
When a Harvester is on that screen, Tier 3 joins the same Passport play automatically. No special wrap. No second creative path.
Honest in vTrust Score
vTrust Score only scores layers that are really there. If Harvester is missing, glass credit is not invented.
The simple idea
So here is the picture.
A second set of eyes on the screen
Think of a security camera for the ad. Not for the people walking by. For the panel itself.
The player can say “I sent the file.” Harvester says what the glass showed.
That record is Proof of Display: patented, independent, and buyable as its own metric.
Patented · UK & US
Vojo's Proof of Display method is protected in the UK and US, with EU coverage progressing. The point for buyers is practical: this is not a software ping dressed up as glass proof.
EU application pending.
How it works
Three beats. Every covered play.
Read. Match. Prove.
The same three beats on every play that Harvester covers.
Read the glass
An independent sensor watches the screen itself. Separate from the player. Separate from the software log.
Match the campaign
What the sensor sees is matched to the content fingerprint for the scheduled campaign. Right creative. Right panel.
Log Proof of Display
A matched read becomes a Proof of Display record: timestamped, tied to campaign and screen. Evidence, not a claim.
The sensor samples the panel itself.
Awaiting match
campaign · screen · timestamp
The sensor is separate from the player and from the playback log, so the record does not depend on the thing being checked. Colours shown are illustrative.
Truly independent
And this is the part that makes it evidence rather than a claim.
Independent of everything, including us
Independence has two halves: who is doing the reporting, and where they are standing. An operator log fails both. Passport is a genuinely third-party report, but it still reports from inside the render. Only a sensor is outside the playback path entirely.
The operator log
Written by the seller, about the seller. Independent on neither count.
Passport · Tier 2
A third-party report the operator cannot author or edit — but it runs inside the player's render, so it inherits whatever that render does.
Harvester · Tier 3
Third party and outside the playback path. A separate device looking at the panel, owing nothing to the software being checked.
Neither Vojo layer is the operator's own account, and neither needs Vojo to have delivered the ad. That already puts both ahead of a playback log. The difference between them is vantage: Tier 2 reports from inside the render, Tier 3 stands outside it.
Which is why Proof of Display is the ceiling. The sensor watches the glass. Whatever put the picture there — our stack or somebody else's — it either appeared or it did not.
Why a log is not enough
A log is not the glass.
What Proof of Display catches
A scheduling log proves content was sent. It cannot prove a screen was on, showing the right creative, and actually lit.
Wrong or missing creative
Confirms the creative that appeared matches what was booked, not only that a play was dispatched.
Screen faults a log never sees
Black screens, frozen frames, and display faults show up in continuous sampling. A playback log often stays quiet.
Downtime vs delivered play
Because it watches the glass, Harvester can tell delivered content from a panel that quietly went dark.
The screen was off
The playback log said
✓ Played in full
The glass said
Dark panel. Nobody saw anything.
The frame was frozen
The playback log said
✓ Played in full
The glass said
One still image held for the whole slot.
The wrong creative ran
The playback log said
✓ Played in full
The glass said
A different advertiser's spot on the glass.
In every one of these the log does not go quiet — it reports a successful play. That is the difference between evidence that is incomplete and evidence that is wrong, and it is only visible to something watching the screen rather than the software.
With the rest of Vojo
Two layers. One play.
Passport carries the ad. Harvester proves the glass.
Passport
Watches from inside your ad
Tier 2 content-level check-in. Travels with the creative. Nothing to install on the operator side.
Harvester
Watches the glass from outside
That is Proof of Display. Use it alone, or both together when a screen has a Harvester. See the difference.
vTrust Score scores every layer that is actually there. More on Passport and vTrust Score.
Who fits Harvester
Though it is not the right fit everywhere.
Screens where the proof pays for itself
A sensor per screen is a real cost. It earns that back where verified delivery changes what the slot is worth, or what an argument costs you.
Premium and large-format
Roadside, retail flagship, stadium bowl. Slots priced high enough that a buyer will ask what actually ran, and high enough that verified delivery lifts the rate.
Rate-card upside
Networks that get audited
Agency or brand buyers who reconcile your numbers against their own. When the count is provable you can stop padding every campaign with free impressions to cover the margin of error.
Fewer disputes
Estates you inherited
Mixed hardware, uneven maintenance, no reliable picture of which panels are genuinely lighting up. The sensor tells you what the logs will not.
Ground truth
And where it is not worth it. On low-value or transit inventory that nobody audits, a sensor on every screen is money you will not get back. Passport rides in the creative at no hardware cost and covers those screens perfectly well. Fit Harvester where the argument is expensive, not everywhere.
Compare with PassportHow you buy it
Buy the glass KPI you need.
Standalone KPI. Or deeper stack.
Buy Proof of Display alone
Attach Harvesters to the screens that need independent verification. Sell verified inventory without bundling the rest of the stack.
Or deepen the Passport path
When Harvester is present, Tier 3 feeds the same play Passport already carries. vTrust Score rolls every present layer into one comparable number.
Works with any standards-based player. No Vojo player required. Attach Harvester to the screens you want to verify and premium-price.
Other alternatives
Fair question. Other shapes exist.
What people usually compare us to
Logs, tags, and operator reports all have a place. Here is where Harvester goes further, without the brand-name mud fight.
Alternative
Player / CMS playback logs
Software says the file was scheduled or sent to the screen.
Where it is fine
Useful for operations and basic delivery tracking inside one network.
Where Harvester goes further
Cannot prove the panel was on, bright, or showing the right creative. That is the Harvester job.
Alternative
Creative tags without a glass sensor
Measurement rides in the creative or a panel-side ping.
Where it is fine
Strong for content-level check-in across networks (Passport Tier 2 lives here).
Where Harvester goes further
Still not an independent eye on the glass. Proof of Display needs Harvester.
Alternative
Trust the operator report alone
Buy-side accepts seller-side proof of play.
Where it is fine
Fast when relationships are tight and stakes are low.
Where Harvester goes further
Advertisers increasingly want third-party glass evidence. Harvester is that evidence.
Last things people ask.
Questions people ask
What is Vojo Harvester, in one sentence?
Harvester is an independent sensor that watches the screen and produces Proof of Display: Tier 3 confirmation of what physically appeared on the glass.
Is Proof of Display the same as Passport?
No. Passport is Tier 2: content-level verification inside the creative wrap. Proof of Display is Tier 3 from Harvester watching the glass. Different layers. They work together when a screen has a Harvester.
Do I need the Vojo player?
No. Harvester watches the screen, not the software. It works with standards-based players and signage systems you already run.
Does Passport need a special setup for Harvester?
No. If a Harvester is fitted on that screen, Tier 3 joins the same Passport play automatically.
How does this relate to vTrust Score?
vTrust Score takes every layer into account: Passport Tier 2, and Tier 3 Proof of Display when Harvester is there. If Harvester is not fitted, glass credit is not invented.
Can I buy Proof of Display without Passport?
Yes. Proof of Display is a standalone glass KPI. Buy it for the panels that need hard proof, or fold it into the wider Vojo stack when those layers are present.
Proof of Display
The glass doesn't lie. Prove it that way.
Fit Harvester where buyers need hard glass proof. It works alone, or deepens Passport and vTrust Score on the same play when it's already there.
- Independent of the player
- Tier 3 Proof of Display
- Auto-joins Passport
20 minutes. Live panel or sample report. Plain answers.