Proof of completion for field service

A completion sign-off is not proof the job got done

Last updated July 16, 2026

Proof of completion for field service is not a checkbox that says the job is done. It is a record made at the job: a live photo, the location, and a time the technician cannot set. Most field-service tools mark a work order “complete” when the tech taps a button, which is a claim, not evidence. This surprises people, but it shouldn’t: the button records that someone said the job was done, nothing more. LockProof records the job itself, sealed so the record holds up when a customer, an adjuster, or an auditor asks.

A sign-off is only as good as the proof behind it

Between 2015 and 2021, a supplier called DRI Relays sold the Defense Department electrical relays and sockets it certified as meeting military specifications. The certification was the product: a signed statement that the required tests had been run and passed. They had not been. The parts shipped, the paperwork said tested, and the testing simply never happened. DRI’s parent company later disclosed the gap, and in April 2025 DRI agreed to pay $15.7 million to settle False Claims Act allegations. Strip away the defense contract and the dollar figure and what is left is ordinary: a sign-off said the work was done, and the proof behind the sign-off did not exist. Reported by the U.S. Department of Justice and Constantine Cannon.

A sign-off is a claim about work, not the work itself. The gap between the two does not care whether the job is a military-grade relay or a Tuesday service call. In field service the claim usually arrives as a tapped button. The technician marks the work order complete, and the dispatcher, the customer, and the adjuster downstream are all trusting the tap.

The button records a claim, not the work

Here is the mental model most field-service software runs on: a work order marked done means the job got done. It holds right up until someone disputes it, and then it comes apart in one step. The button does not record the work. It records that a person pressed a button. Nothing in a checkbox ties the claim to the site it was made about, the time the work was actually finished, or the condition it was left in. An e-signature does not close the gap; it adds a name to the claim. Proof has to come from the job, not from the record of someone asserting the job is finished.

How the record gets made

The alternative is to capture the finished job at the moment it is finished, in a way that is boring to produce and hard to change after the fact. Four steps, no app for the technician, and nothing typed in later.

  1. Dispatch the job. The technician gets a text with a link. No app to install, no login.
  2. The link opens the camera. Gallery uploads are blocked, so the photo of the finished work is taken on site, not pulled from a camera roll.
  3. The record seals itself. GPS and a server-set time attach at capture, and a SHA-256 fingerprint makes any later change detectable.
  4. You see it, and can share it. The completed job lands on your dashboard, marked done, late, or missed, and shares as one signed link when a customer asks.

What a completed job carries

  • A live photo of the finished work, captured through the link (gallery blocked)
  • GPS recorded at capture, checked against the site’s expected location
  • A server-set timestamp the technician cannot change
  • A SHA-256 chain of custody on every record
  • A dashboard that marks each job done, late, or missed
  • An Evidence Vault you can search by site, technician, or date
  • A shareable signed proof link that expires after 7 days
  • No technician app or login, in English and Spanish

Sign-off vs. proof

The two look alike in a dashboard. They are not the same the day a customer pushes back.

What the record carriesA completion sign-offLockProof
Shows the finished workA checkboxA live photo
Tied to the siteNoGPS at capture
Time you can trustTyped or device timeServer-set
A later edit is detectableNoSHA-256 chain of custody
Filed and searchableIn the work orderEvidence Vault
Ready to share in a disputeThe sign-off onlyOne signed link

See a finished example in a sample verified record, or how it fits field service teams. And if a customer ever disputes a job, the proof is already filed, dispute-ready.

Common questions

What counts as proof of completion for field service?

Proof of completion is a record made at the job, not a claim entered afterward. It carries the finished work as a live photo, the GPS where it was taken, and a server-set time the technician cannot change. A work order marked done is a claim; a captured, sealed record is the evidence behind it.

How do you prove a technician was actually at the job site?

The capture records GPS the moment the photo is taken and checks it against the site's expected location. A photo taken two blocks away, or an hour later, shows as exactly that. It is not a tracker running all day — one location, fixed to the finished job, not a trail of the technician's movements.

Can a completion photo or its timestamp be faked?

The link opens a live camera only, with gallery uploads blocked, so a photo from last week can't be attached. The time is set by the server, not the handset, and reminder timing is randomized. Every record carries a SHA-256 fingerprint, so any later edit stops matching and is detectable.

What do you show a customer who disputes the work?

One record: the live photo of the finished job, its GPS, the server time, and the full event history, shared as a single signed link. The customer sees the work, where it was, and when. The dispute moves from your word against theirs to a record that stands on its own.

See proof of completion on your own jobs

Book a 15-minute demo and watch a finished job come back as a verified record instead of a checkbox: the live photo, the place, and a server-set time the technician cannot change.