Sly Fox Appointments

The offline appointment book for solo service providers whose clients expect absolute discretion — tattoo artists, nail techs, stylists, cleaners, and anyone whose client list is theirs alone. Names, photos, and notes stay encrypted on your device. No cloud. No lock-screen previews. Nobody else's business.


BUILT FOR YOUR PRACTICE

• Tattoo artists and piercers — photos of unfinished work on bodies your clients may not have told anyone about; regulars who can't overlap in the waiting room.
• Nail, beauty, and lash — clients who expect discretion about who else you see, how often, and what they ask for.
• Cleaners, organizers, and mobile pros — in people's homes with your phone in your pocket, holding their schedules, addresses, and routines.
• Anyone whose client list is itself confidential — discreet and referral-only practices where a name on a screen is a breach.


THE SITUATIONS YOU ACTUALLY FACE

Your next client walks in early while you're still finishing. Your phone is on the counter, lit up with a notification carrying the name of the person in your chair. The bag goes missing at the gym. A nosy partner picks up the unlocked phone "to check the time."

Privacy isn't paranoia. It's the ordinary moments when your device leaves your hand and your clients are on the screen.


HOW THE LOCK HOLDS

Even when someone is holding your unlocked iPhone, your book stays sealed.

• Every cold start, every return from background — the app re-locks. A PIN gate is the first thing you see.
• Data on disk is ciphertext, not a calendar. The two SQLite databases are sealed with SQLCipher (AES-256 page encryption); the most sensitive columns are wrapped a second time with AES-GCM.
• Keys are not stored. They are derived from your PIN at every unlock using Argon2id at a memory-hard work factor. Without the PIN, the key cannot be reconstructed — and brute-forcing it is ruinously slow.
• Four wrong PIN attempts re-lock the vault and clear the in-memory key.
• Clients you flag sensitive sit behind a separate key and a separate PIN. Their notes, photos, and session details stay sealed even when the everyday vault is open.
• A duress PIN opens a believable decoy vault — a plausible roster, a handful of retail entries, nothing real.
• A privacy overlay drops over the view the instant the app backgrounds, so the iOS app-switcher thumbnail contains nothing recognizable.


NOTIFICATIONS THAT SAY NOTHING

Your lock-screen banner reads "Appointment at 14:30." No name. No address. No service. The reminder gets you to the door; the detail waits behind the PIN.


PHOTOS THAT NEVER TOUCH YOUR CAMERA ROLL

In-app camera capture for references, before/after shots, and works in progress. A zero-permission picker for imports. Plaintext bytes never hit the disk. Nothing about your client appears in the system Photos library or its iCloud backups.


NO CLOUD. NO CALENDAR HANDOFF. NO SPOTLIGHT.

Sly does not sync to iCloud, hand off to the iOS Calendar, expose entries to Spotlight, donate to Siri, or open Maps, tel, mailto, or sms links. Your client list does not exist on any server we operate. There is no server we operate.


OPEN SOURCE, AUDITABLE

The entire codebase is published. The cryptography is documented, tested with realistic Argon2 parameters, and subject to mutation testing. Discretion you cannot inspect is just a promise. This one you can read.


WHAT YOU GET

• No subscription.
• Optional one-time purchase: Encrypted Transfer, to move your vault to a new iPhone.
• No account. No sign-up. No email collected.
• Works fully offline. The app makes no network calls.
• iPhone, iOS 17 and later.