You are buying a licence to use Proof. Apple is the seller and handles the money. Everything you measure stays on your device. The rest of this page is the detail behind those three sentences, written to be read rather than skimmed past.
Proof is made by Warren Labs, a trade name of Free River Studios LLC, a Montana limited liability company operating from Livingston, Montana, United States. "We" and "us" below mean Free River Studios LLC.
Apple is the seller. Proof is sold through the App Store, and Apple handles the payment, the tax, the receipt and the refund. Your contract for the transaction is with Apple and is governed by Apple's terms, which you accepted when you set up your Apple Account. This page covers the software itself, and the relationship between you and us. Both relationships are real and they cover different things.
These terms are Proof's. The Warren Labs audio plugins are sold somewhere else entirely, under their own terms, and that page does not apply to anything you buy in the App Store.
A licence to use the software, not the software itself and not its source code.
There is one tier. Everything Proof can do is in it. There is no professional edition, no add-on and no feature you can unlock separately, and we do not intend to add one.
You pay for it once. There is no subscription, nothing renews, and there is no second thing to buy later. The price is shown in the app and on the App Store, and it is not repeated here: a price written in two places is a price that will eventually disagree with itself.
What the licence lets you do. Use Proof on the devices associated with your Apple Account, as Apple's own terms allow, including for paid commercial work, with no royalty, no extra licence and no reporting. Proof is a Universal Purchase: one purchase covers the Mac, iPad and iPhone versions.
What it does not let you do. Resell, rent, redistribute or sublicense it. Reverse-engineer, decompile, or take it apart for use in another product.
Proof has a free half that needs no purchase and no account, and it is not a trial or a teaser.
You do not lose anything you measured, ever. The purchase does not expire, so there is no lapse to describe here, and even the free half can open, check and read every record you have written. We do not hold your data hostage, and there is no state of this app in which a measurement you made becomes unreadable.
Proof is not a subscription. Nothing renews, nothing is charged to you a second time, and there is no date you have to get ahead of. If you are looking for the paragraph that tells you how to cancel before you are billed again, there isn't one, because there is no next bill.
There is no timed free trial either, and that is deliberate. A week is long enough to form an impression of an instrument and not long enough to trust one. So the free half of Proof is not a countdown: the live instruments and reading records are free for as long as you keep the app, and you can go on using them without ever buying anything. That is the trial, and it does not end.
Which means there is no countdown in the app, no "trial expired" screen and no nag. The app only ever asks whether it is entitled right now.
Proof 1.0, and you own it. The purchase does not renew, there is nothing to cancel, and it does not expire. The app keeps working for as long as your hardware and operating system will run it, whatever we do afterwards.
What a future major version will cost, we have not decided. It might be free to you, it might be a separate purchase. Rather than write a number we would have to take back, we are telling you it is open. Updates to the version you bought are not in question: those are just us fixing and improving what you already have.
Apple issues refunds for App Store purchases, and we cannot. We never see the transaction, there is no order number on our side to look up, and Apple gives developers no way to refund one.
Ask Apple at reportaproblem.apple.com, signed in with the Apple Account you bought with. Choose the purchase, pick a reason, submit. Apple usually decides within a couple of days.
An App Store refund is Apple's decision, under Apple's terms and under whatever consumer law applies where you live.
If you are in the UK or the EU, Apple publishes terms for your region, and they are what govern this. The two we read (the UK's and Ireland's) each give you a fourteen-day right to withdraw from an order, exercised through Apple and not through us, and each states an exception to it:
"You cannot cancel your order for the supply of Content if the delivery has started upon your request and acknowledgement that you thereby lose your right of withdrawal."
Apple Media Services Terms and Conditions (Ireland), read 18 September 2026. Apple's UK page carries the same sentence, calling the same thing your cancellation right.
Whether installing Proof starts delivery in that sense is Apple's call and the law's, not ours, and we are not going to tell you the answer we would prefer. Ask Apple. And your statutory rights below stand whatever the answer is: nothing on this page takes away a right the law gives you.
If Apple turns you down and you think that is wrong, write to us anyway. We cannot overturn their decision and we are not going to pretend otherwise, but if Proof did not do what we said it does, we want to know, and that is worth more to us than the sale.
Our general refund policy is at warrenlabs.com/refunds, which already explains this distinction for another App Store product.
This section is the boundary of what Proof claims. It is not a retraction of it.
What Proof claims, and we stand behind it. Every reading Proof prints is reported against a noise-and-distortion floor that the instrument measured on the equipment in front of it. A reading that is clear of that floor is printed with the number of digits the floor entitles it to. A reading at or under the floor is printed as an inequality with no digits, because the honest statement is "quieter than this instrument can hear". Most analysers print a number there. Proof does not, and that refusal is the product. Nothing on this page is an admission that Proof's numbers are vague, unreliable or not to be believed. They are stated with their uncertainty attached, which is more than most tools in this class do.
What that does not make Proof. It is not an accredited, certified or traceable instrument. We provide no calibration certificate and no traceability to a national standard, and we hold no accreditation of any kind. Proof measures through hardware we did not make, in a room we have not seen, operated by someone we cannot supervise. Where the app supports calibration (sound pressure level can be calibrated against an acoustic calibrator you supply), the accuracy of that calibration is the accuracy of your calibrator and your microphone, not something we can warrant.
So, plainly: do not use Proof as the instrument of record where the number itself carries legal, regulatory or safety weight. That includes, and is not limited to:
Those uses need an instrument with documented calibration and traceability, usually to a defined class or type, operated to a published method. Proof is not one and does not claim to be. The sound pressure level meter and the noise dosimeter report a measured quantity and prescribe nothing; they are not a substitute for a class- or type-rated sound level meter where one is required.
About the records specifically. A Proof record carries a content hash. That hash proves the document has not been altered since it was written, and anyone can check it without our software. It does not prove the equipment was set up correctly, that the right thing was measured, or that the person holding it is who they say they are, and the format makes no such claim. A record is a statement about what this instrument measured, on this equipment, at that moment. Treat it as exactly that.
The distinction we are drawing is between honesty and authority. Proof is honest about its own uncertainty. It is not an authority, and no amount of honesty makes it one.
A Proof record is your data. You made it. These terms give us no claim on it of any kind.
Nothing you measure leaves your device. Proof has no account, no server of ours, no analytics, no crash reporting and no telemetry. Nothing you measure, and nothing about how you use the app, is sent to us or to anyone else, because there is nowhere for it to be sent: we operate no service for Proof to talk to. If you want a record to go somewhere, you export it and send it yourself.
There are two things the app reaches out for, and neither carries anything you measured:
The privacy manifest that ships inside the app declares no data collected and no tracking, and our App Store privacy answer is Data Not Collected. This page and that manifest have to agree. If they ever disagree, the manifest is what is actually running and this page is the thing that is wrong.
You may use, publish, sell, keep or destroy your records as you like. You need no permission from us, you owe us no attribution, and there is no licence back to us hiding anywhere in this document. The record format is documented and the rule for checking one is plain text, deliberately, so that a record can be checked with a hash function and none of our software at all, including in a future where we no longer exist.
We cannot recover a record you lose. We never had it. Back up your device.
Updates within the version you bought are included. We may add, change or remove features in an update, and we will not pretend otherwise here so that we can quietly change our minds later.
What we will not do is take away the thing you paid for. If Proof's business model ever changes, a licence already sold keeps working for the version it bought, and existing customers will be told directly rather than by us editing this page.
Proof is provided as it is. We do not warrant that it is free of defects, that it is fit for any particular purpose, that its results are accurate for your equipment, or that it will run uninterrupted. No software vendor can honestly promise those things, and a measurement tool least of all.
That paragraph is a legal backstop, not a shrug. If Proof gives you a wrong answer, tell us. We would rather fix the instrument than point at this section: an instrument whose maker is not interested in its errors is not an instrument.
To the fullest extent the law allows, our total liability to you arising out of or relating to Proof is limited to the amount you have paid for Proof.
We are not liable for indirect, incidental, special or consequential loss, including lost profits, lost work, lost data, or loss arising from a decision you made on the basis of a measurement. The section above on what Proof's numbers are for is the reason that last clause is there, and it is why that section is written as plainly as it is.
Nothing in these terms removes rights the law gives you. If you are a consumer in the European Union, the United Kingdom, or anywhere else with mandatory consumer protection, those rights apply on top of this page and override anything here that conflicts with them.
If we change this page, the change applies to purchases made after the change. It does not reach backwards into a licence you already hold. The date at the bottom is when it was last touched.
These terms are governed by the law of the State of Montana, United States, without regard to its conflict-of-law rules. Your separate purchase contract with Apple is governed by Apple's terms.
jamey@warrenlabs.com. Write about anything at all, including the awkward questions. A real person reads it.