Start with what an invoice proves. It proves that you billed. It does not prove that work happened, or when, or that the joint held at 80 PSI. When a card processor gives you ten days to respond to a chargeback with evidence, the invoice is the one document you definitely have and the one that helps least.
A report that holds up has six properties. None of them is exotic. All of them are hard to add afterwards.
1. Written on the day
The write-up — what was found, what was done, what was tested — has to exist before anyone knows there will be an argument. A note reconstructed for the dispute reads like one. A note written at 10:46 on the day, by the person who did the work, reads like a record. FieldLog's notes are captured on site and filed with the photos; there's no "write it up later" step for the argument to leak into.
2. A time on the picture
Metadata is stripped the moment a photo is texted or emailed. A timestamp burned into the pixels is not. If a customer forwards your photo to their brother-in-law who "knows about plumbing", the time goes with it. (Where it was taken does not — that lives on the report, on purpose.)
3. A name on the work
"One of my guys" is not a witness. D. Okafor, 09:14 is. Every FieldLog photo records which technician took it, which is also why we price by size rather than by seat — shared logins put the same name on everything and the property disappears.
4. A filed line
Who filed the report, when, and from where. It is the moment the job closed on the record, and it is the line that ends the "when was this actually done?" phone call. It's set in the same monospace on every report so that it reads as what it is: a stamp, not prose.
5. Sent the same day
A report the customer received in August is hard to argue with in March. The share link and the sign-off page record when the customer was sent the report and, if they answered, what they said and when. We deliberately give "Yes, all good" and "Something's not right" equal weight — a sign-off page that makes disagreement hard is not a sign-off, it's a trap, and a trap is worth nothing when it's questioned.
And we never use the word "verified" about a sign-off. No identity check is performed. The only claim ever made is: the customer was sent this exact report and said this about it, at this time, and nobody has changed either since.
6. Unchangeable after filing
This is the one people skip. A record you can edit is a record you could have edited. FieldLog's filed reports are immutable — the database refuses the change, for everyone including us. Photos can only be attached in the same moment the report is created, so nothing can be slipped in later either. Corrections are a new report that points at the old one, with both kept.
What none of this guarantees
FieldLog is a record, not a legal outcome. No app decides how a dispute ends. What it guarantees is narrower and more useful: when one starts, your side of it is already written, stamped, named and filed — and the other side has to explain why a contemporaneous record is wrong, rather than you having to explain why you have nothing.