Your opponent notes are tactical secrets. Store them like it.

Think about what an honest opponent journal actually contains.

Your reads on every rival in your division. Your assessment of their weaknesses — and the plans you intend to use at the next competition. And the most sensitive part: your own file. The admissions of what breaks your game, written plainly, because the journal only works if you don’t flatter yourself.

Now ask where notes like that should live. On the servers of a company that could get acquired, breached, or bored? Readable by whoever operates the database, governed by a privacy policy that can change with thirty days’ notice?

We didn’t think so either. So we built OpponentBook on an architecture the industry calls BYOS — bring your own storage — and it changes the privacy conversation from a promise into a structure.

“We don’t read your data” vs. “we can’t”

Almost every app with a privacy page makes the first claim. It’s a policy statement: data sits on the company’s servers, employees could technically access it, and a policy — enforced by good intentions and legal exposure — says they won’t.

OpponentBook makes the second claim, and it’s a different kind of sentence. Your journal — every observation, reflection, training entry, photo and clip — is written to your own Google Drive, Dropbox or iCloud. Our servers store your login, your subscription tier, and an anonymous skeleton of IDs and dates so your lists load fast. Your words are not on our side of the wall. We cannot read your notes for the same reason a stranger can’t read the notebook in your gym bag: we don’t have it.

This isn’t a premium feature, and it isn’t a mode you enable. It’s how the product works, for every user, on the free tier, forever.

For the threat model that includes Google

In standard mode, your storage provider can technically read files on your drive — that’s true of everything you keep there. Most athletes are fine with that; Google has no interest in your épée notes.

If you’re not fine with it, one switch turns on end-to-end encryption: your notes are sealed with AES-256-GCM on your device before upload, and the provider stores ciphertext it cannot open. The key derives from a password only you know — which means if you forget it, nobody can recover your notes. Not us, not Apple, not anyone. We state that trade-off in bold when you enable it, because a privacy promise that hides its costs isn’t honest, it’s marketing.

Honesty has a feature list

The same thinking shows up in smaller places:

• The review tracker — the feature that correlates preparing with winning — stores its events on your storage too, next to your notes. One switch stops it; one button erases its history.
• AI features run only when you tap them. Nothing scans your book in the background. Never press the button, and nothing ever leaves your device for a model.
• This website has no third-party analytics. It seemed strange to advertise privacy through a page that spies on you.

Your reads, your weaknesses, your plans. Keep the book — and keep it yours.

Start yours free — the whole journal, on your own storage.