Period & cycle tracking
Your cycle, only on your phone.
A period tracker with no accounts, no analytics, and no servers. Your data lives on your device. That's the whole product.
No account · No analytics · No telemetry
A period tracker that respects you.
Most period apps have a problem. In 2021, the FTC settled with Flo Health over sharing users' menstrual data with Facebook and Google despite promising not to. In 2025, a $56 million class-action settlement followed. These weren't edge cases — they were the business model. Period data is valuable to advertisers, insurers, and data brokers, and the apps that collect it have every incentive to sell it.
Vellum works differently. There are no servers, no user accounts, no analytics SDKs, and no marketing list. Your cycle data is stored in a local SQLite database on your device, with notes and symptom fields encrypted at rest using AES-GCM with a 256-bit key that lives in your phone's hardware-backed secure store. We never see it. We can't. That's not a policy — it's an architecture.
What you get: a full calendar view, cycle length predictions, daily symptom and mood logging, and pattern insights over time. Everything a good cycle tracker should do, without anyone watching over your shoulder.
The app.
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A calendar that learns from you, not about you.
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Log what matters. Privately.
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See your patterns over time.
What we don't have.
- No user accounts
- No analytics or telemetry
- No servers storing your data
- No third-party SDKs
- No advertising network
- No data sharing with anyone, ever
We can't leak data we don't have. That's the whole design.
Simple pricing.
Free
Free
Forever
- Unlimited cycle logging
- Last 3 cycles of history
- Basic predictions
- Local notifications
Lifetime
$9.99
One-time purchase
- Everything in Free
- Full history, all insights
- PDF export
- Four accent themes
No subscription. No ads. Pay once, yours forever.
Questions.
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Where is my data stored?
On your device only, in a local SQLite database. Notes and symptom fields are encrypted with a key that lives in your phone's hardware-backed secure store (iOS Keychain or Android Keystore). That key never leaves your device.
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What happens if I lose my phone?
Your data is gone. We can't recover it because we never had it. Use the export feature in Settings to keep your own backup — Vellum can produce an encrypted JSON file or a printable PDF that you save wherever you choose.
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Is this medical advice?
No. Vellum is a tracking tool, not a medical device, contraceptive method, or fertility treatment. Predictions are estimates based on your tracked history. If you're tracking for conception, contraception, or a health condition, please consult a clinician.
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Can I share data with my doctor?
Yes. Export to encrypted JSON or a printable PDF from Settings, then share the file however you choose. Vellum itself never uploads the file anywhere.
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Why no Apple Health or Google Fit integration?
Maybe later. For v1, we kept the boundary as simple as possible: data lives on your device, full stop. Adding Health integrations would require careful review of what leaves the device and under what conditions. We'd rather ship that right than ship it fast.
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Who built this?
A small independent developer who got tired of period apps that exist to sell user data. Questions? support@dyeverse.co