Zero-knowledge habit tracking. Your growth belongs to you.
Hi Product Hunt! π
I'm Mark, solo dev and co-founder of Moss Piglet β a privacy-first public benefit company.
Habit tracking is personal. Your goals, your struggles, your progress β that's some of the most intimate data you can generate about yourself. So why does every habit tracker out there store it in plaintext on their servers?
Metamorphic is a zero-knowledge encrypted habit tracker. Your data is encrypted in your browser before it ever leaves your device. The server never sees your habits, your goals, or your progress. Not even we can read it.
How it works:
Password-derived public-key cryptography runs entirely in the browser
End-to-end encryption by default on every plan β not a premium add-on
The server stores only encrypted blobs it can never decrypt
What you get:
Habits & streaks β build consistency and track your check-ins
Reflections β journal on your progress privately
Goals & milestones β set targets and track meaningful progress
Schedule / calendar β plan your habits around your life
Progress insights β see how you're actually doing over time
Family groups β up to 6 people with shared habits, shared goals, and a group dashboard
Data export β your data, your way out. Always.
Every plan gets E2E encryption. The free tier gives you 5 habits with 7 days of history and full streak tracking β no credit card, no catch. Paid plans unlock unlimited habits, full history, reflections, goals, insights, and family features.
Why I built this:
I believe privacy is foundational to how we grow as people. You can't reflect honestly or push yourself if you know someone's watching. Metamorphic is built to give you that space.
It's built with Elixir and Phoenix LiveView, bootstrapped with zero investors, and run as a public benefit company β so the incentive is always the product, never your data.
I also built MOSSLET, a privacy-first social network with E2EE messaging and Bluesky interop, using the same encryption architecture that inspired Metamorphic.
Launch offer: Use code PH20SAVE for 20% off 6 months (good until April 30, 2026 at 11:59pm).
Would love to hear what you think β happy to answer any questions about the zero-knowledge architecture or anything else. π
Replies
Metamorphic
Metamorphic is now post-quantum resistant
Your habits, goals, reflections, and personal data are now protected against both today's threats and tomorrow's quantum computers.
We've upgraded Metamorphic's encryption architecture to use a hybrid post-quantum KEM β combining classical X25519 with ML-KEM-768 (NIST FIPS 203), the same approach used by Signal, Apple iMessage, and Chrome. Both algorithms must be broken simultaneously to compromise your data. If either one holds, your keys stay safe.
What changed
Hybrid key distribution β Every key seal operation now uses ML-KEM-768 + X25519, providingresistance to both classical and quantum attacks
Automatic migration β Existing users get post-quantum protection on their next login. Your browsergenerates new hybrid keys and re-seals all your existing data in the background. No action required.
Version-tagged ciphertext β We introduced a v1/v2 format so legacy-encrypted data continues to workseamlessly while all keys are progressively upgraded to quantum-resistant wrapping
SHA3-256 key combiner β The two shared secrets are combined with full transcript binding (ciphertextsand public keys included), following the IETF hybrid KEM draft for proper domain separation
What didn't change
Zero-knowledge guarantee β We still can't read your data. Everything is still encrypted and decryptedin your browser.
Three layers of encryption at rest β Client-side E2E (XSalsa20-Poly1305), application-layer (AES-256-GCM), and infrastructure disk encryption (LUKS) all remain in place.
No price change β Post-quantum encryption is included on every plan, including free. Privacy is not apaid upgrade.
Why this matters for a habit tracker
Your habit data might seem low-stakes, but it reveals your daily routines, health practices, mental health patterns, personal goals, and the structure of your life. Adversaries with a "harvest now, decrypt later" strategy could capture encrypted data today and wait for quantum computers to break classical encryption years from now.
We'd rather not give them the chance.
Technical details
We use libsodium (via libsodium-wrappers-sumo) for classical cryptography and @noble/post-quantum (from the noble cryptography suite, whose core libraries have been audited by Cure53) for ML-KEM-768. No custom or proprietary cryptography.
Full details are on our updatedΒ encryption architectureΒ page.
Metamorphic
Quick update β Metamorphic was just featured as the #1 pick in We Are Founders' "Best Habit Tracking Apps" roundup for 2026. We're the only zero-knowledge encrypted option on the list. Also recently added .ics calendar import/export and moved data export to the free tier. More coming soon.