Catchlight.
Catchlight is a private notes, reminders and tasks app for iPhone. It is the first thing Considus built, and the reason the studio exists.
catchlight.app covers what it does, screen by screen. This page is the shorter answer to a different question, why it was built at all.
Why it exists
In early 2026 the UK government forced Apple to withdraw Advanced Data Protection from iCloud. That was the feature giving Apple Notes and Reminders genuine end-to-end encryption. Overnight, the notes app on millions of phones went from private to readable by someone other than its owner.
The gap that opened was not for another notes app. There are hundreds. It was for one that felt as considered as the tool it replaced, and that treated encryption as the floor rather than a paid tier.
What makes it different
One kind of thing. Most apps make you decide up front whether something is a note, a task or a reminder. Catchlight does not ask. You capture a Take, and it becomes whatever it needs to be, gaining a checkbox or a time when you give it one.
Encrypted because that is correct. Not as an upgrade, not as a badge on the pricing page. Your content is encrypted before it leaves the device, and the studio cannot read it. That is a structural property, not a promise.
Your data stays yours. Sync runs through your own iCloud or Dropbox rather than a Considus server. There is no account to create and nothing of yours sitting on infrastructure the studio controls.
Priced honestly. One fair annual price for the whole app. No feature held back to sell later, no advertising, and nothing about you sold to anyone.
White papers
Three technical papers, published before Catchlight launched rather than after, so they can be checked rather than taken on trust. Each one is also a PDF.
The Catchlight encryption architecture
How a note is sealed, where the keys live, and what the design deliberately does not protect you against. The key hierarchy, the ciphers, storage at rest, and recovery when every device is gone.
Who might read your notes
A threat model taken adversary by adversary. What a thief, someone in your household, a cloud provider, Apple, a warrant and the studio itself can each actually do, and which of them the architecture cannot help with.
How to tell whether a notes app is private
Seven tests you can run on any notes app in an afternoon, none of which need any expertise. Vendor-neutral, and Catchlight is scored on the same seven, including where it loses.
Protecting your notes without Advanced Data Protection
What the withdrawal of Advanced Data Protection actually cost UK iPhone users, why Notes and Reminders were two of the ten categories affected, and what is still in your hands.
What AI features cost you in a notes app
Where a model runs decides what an AI feature costs you in confidentiality. On-device, confidential server compute and ordinary servers compared, with the questions to ask any notes app.
Sync with no server and no account
How two devices agree with no server and no account, what the design gives up to get there, and the measured provider constraint it imposes.
Where it is
Catchlight is in late development, heading for TestFlight and then the App Store. The waitlist is open at catchlight.app, and joining it is the way to hear when it ships. The longer account of how it got here is in the Journal, Catchlight, where it stands.
Its own terms
Catchlight has its own privacy documentation and terms, separate from this site. The studio's privacy policy covers considus.com only.