Your library stays yours.
Refrain was built around a simple idea: it shouldn't need your data to work. Your Kindle highlights live on your devices. Your devices sync through your own iCloud. Refrain's finding runs locally.
There is no Refrain account. There is no Refrain cloud. And there is nothing on our side that can read your library.
The short version
Your Kindle
Amazon
Refrain
Your iPhone · iPad · Mac
Your iCloud
Your devices stay in sync
The important part
Your library never goes up to us. The intelligence runs where your library lives.
There is no Refrain cloud.
Most apps work by sending your data to a company's servers. Refrain doesn't. Your library is stored locally on your devices. iCloud syncs it between your own devices. Refrain doesn't operate a backend that receives, stores, indexes, or processes your reading.
That's not a privacy policy. It's the architecture.
Your password goes to Amazon. Not us.
When you connect Kindle, Refrain presents Amazon's own sign-in page inside the app. Your Amazon password is entered into Amazon's page. Refrain never sees it, stores it, or transmits it.
Once authenticated, Refrain reads your Kindle notebook and imports your passages directly onto your device. Older Kindles and sideloaded books can use My Clippings.txt instead.
Nothing from your library is uploaded to Refrain.
Your library lives on your devices.
Refrain uses Apple's native storage and sync technologies to keep your library available across iPhone, iPad, and Mac. Your passages, books, notes, insights, threads, and other Refrain data are stored in your private iCloud database when sync is enabled.
When you're offline, changes wait locally. When you're connected again, your devices catch up. The cloud here belongs to you.
Everything that reads across your library runs on your device.
Refrain's finding isn't a request to a remote model.
- Rhymes compares the meaning of passages on your device.
- Threads finds lines of thought across your library and names them there. On devices with Apple Intelligence, Apple's on-device model proposes sharper names — "Money" becomes "Concert Pricing" — and the proposal is accepted only when Refrain's own measure agrees it sits closer to what the thread shares. The naming never leaves the device.
- Search by meaning understands the idea behind your query, on your device.
- Echoes matches your library against a collection of public quotations downloaded to your device.
Across your library: no passage, no note, no derivative is sent anywhere.
One feature reads outward, and it's the one you'd expect. Tap Go deeper and a single brief — one passage, your note, up to three rhymes, the name of a thread, and the questions you've chosen — goes to Apple's Private Cloud Compute. Not your library. One brief, when you tap, and never before.
Nothing is sent anywhere unless you send it.
Built with Apple's stack.
Refrain is built almost entirely with technologies already on your Apple devices.
- SwiftUI
- One native interface across iPhone, iPad, and Mac.
- SwiftData + CloudKit
- Local library storage and iCloud sync.
- Core ML
- On-device passage embeddings and semantic matching, using the Neural Engine when available.
- Natural Language
- Linguistic analysis used to help name threads.
- Foundation Models
- Apple's on-device model helps name threads. Private Cloud Compute reads a Go deeper brief when you ask.
- WebKit
- Amazon's sign-in and notebook sync.
- WidgetKit
- The daily passage on your Home Screen.
- StoreKit 2
- The one-time unlock.
The only third-party code in the entire app is an HTML parser.
How rhymes actually work
Each passage is represented locally in a form that lets Refrain compare its meaning with other passages in your library. When two passages resonate, Refrain calls that a rhyme. A weaker match is a fainter rhyme.
The comparison happens on your device. Your library never needs to leave it.
For the curious: Refrain uses an on-device embedding model to represent passages and cosine similarity to rank their semantic proximity.
Threads are found, not written.
Refrain looks across your library for groups of passages that share a meaningful idea. Those groups become threads. Thread names are chosen on your device from the passages themselves — and on devices with Apple Intelligence, with help from Apple's on-device model, which may propose a sharper title that Refrain accepts only when its own measure agrees. Names you write yourself are never touched.
The name isn't a claim about what you believe. It's Refrain describing what the passages have in common. The books speak. Refrain frames.
The library never goes up. The canon comes down.
Refrain downloads a collection of roughly 50,000 attributed quotations — once. Its vectors are already prepared. When Refrain looks for an echo, it compares your threads against that local collection. The result never requires uploading your library.
And Refrain has a quality bar: if there isn't a genuinely good echo, there isn't one. Silence beats an almost-match.
Insights: no intelligence required. Just you.
An insight is simply something you wrote about a passage or thread. It stays distinct from the book's words and from anything Refrain found. Its origin is permanent. Your insight is yours — Refrain doesn't rewrite it, summarize it, or pretend it came from somewhere else.
Refrain writes the brief. You decide who reads it.
Go deeper composes a plain-text research brief entirely on your device. It can include the original passage and attribution, your note if you wrote one, up to three rhymes, the thread it belongs to, and the questions you've chosen to ask — up to four of eight: In plain words, Why you marked it, The fuller picture, Where it comes from, The best objection, Try it, Read next, One question. Out of the box it asks why you marked it, the fuller picture, the best objection, and one question.
Then you choose who reads it.
In Refrain. One tap on Go deeper sends the brief to Apple's Private Cloud Compute — Apple's servers, running Apple's model. A reading streams back beside the passage and is drawn as it arrives, one section per question. A few hundred words, grounded in the passage, never a book summary. The finished reading is signed Read on Apple's Private Cloud Compute and saved with the passage — an insight that permanently says a model wrote it, the same way your own insights permanently say you. Tap Go deeper on that passage again and the reading is there; ask again for a fresh one.
A reading is a starting point. Sit with its question, and the question rides back with the passage the next time it returns in your daily deck. Respond, and your answer is saved as your own insight on the passage — and the question, answered, stops returning.
What we can promise, because it's our architecture: nothing is sent until you tap — no prefetch, nothing in the background — and the reading comes back to your device, not to us. There is no Refrain server in the path. There's no charge for it, to you or to us.
What Apple says, because it's Apple's design: a request to Private Cloud Compute is used only to fulfill itself, is not stored or accessible afterwards, and the design is published so others can check it. That's Apple's word. We relay it; we don't restate it as ours.
If your device has Apple Intelligence and can't reach Apple's Private Cloud Compute — no connection, or Apple's usage limit is reached — the reading runs on the device itself. Shorter and plainer, the same questions, signed Read on this device.
Hand to your AI. The same brief goes to the standard share sheet. ChatGPT. Claude. Notes. Mail. Something else. Once you hand the brief to another service, that service's terms apply. That's your decision — not Refrain's.
Which devices get which: Apple's Private Cloud Compute needs the current OS. On last year's OS, a device with Apple Intelligence still gets readings, on the device itself. Everything older gets the hand-off — exactly what 1.0 had. The hand-off works everywhere. When a reading can't happen, Refrain says so in one quiet line and offers the hand-off. Never an error dialog.
Nothing is sent until you tap. Nothing comes back to us.
What's next arrived. The rule didn't move.
In August this page said that as Apple's devices grew more capable, Refrain would bring that capability in without changing the promise underneath. 2.0 is that sentence, kept.
A reading beside any passage, written by Apple's model. Thread names chosen with help from Apple's on-device model. A spread on the devices wide enough to hold one.
And the promise underneath, in its more precise form: the finding happens on your device. The one feature that reaches out does so only when you tap — to Apple, never to us. Your reading stays yours.
No dates promised. Better devices. Better Refrain. Same rule.
What does Refrain know about you?
| Data / activity | Who has it? |
|---|---|
| Your Amazon password | Refrain never sees it |
| Your Kindle highlights | Stored on your devices; never uploaded to Refrain |
| Your notes and insights | Stored on your devices and your own iCloud |
| Your reading habits | No tracking or analytics code |
| Which AI app you hand a brief to | Refrain doesn't know |
| The response you get from that service | Refrain never sees it |
| The brief you send with Go deeper | Apple's Private Cloud Compute, only when you tap, to write the reading. Apple's design: used only to fulfill the request, not stored or accessible afterwards. Refrain never sees it |
| The reading that comes back — and any question you sit with, or answer you write | Your device, saved with the passage — and your own iCloud, if you sync. Refrain never sees it |
| Which path you chose — a reading in Refrain, or the hand-off | Refrain doesn't know. There's no analytics code to tell us |
What about Apple? iCloud and Private Cloud Compute are Apple's infrastructure, not Refrain's. Your iCloud data is protected by Apple's security model; Advanced Data Protection can provide end-to-end encryption for additional iCloud data when enabled. Private Cloud Compute is designed by Apple so that a request is used only to fulfill it and is not stored or accessible afterwards — a design Apple publishes for independent verification.
Who does Refrain talk to?
- Amazon
- For the Kindle sync you initiate — your highlights and your books' cover art alike. Your other devices fetch the same covers from Amazon's image server, without your Amazon sign-in.
- Apple
- For iCloud, App Store services, Apple's own optional diagnostics — and Apple's Private Cloud Compute, only on a Go deeper tap.
- getrefrain.app
- For two static downloads: configuration and the Echoes quotation pack.
That's it. There is no Refrain API. No Refrain endpoint of any kind. No analytics service. No tracking service. No user database.
And the app doesn't phone home.
Take it on a plane.
Once your library is imported, everything important works offline: read, return, search, search by meaning, find rhymes, explore threads, write insights, find echoes, write the brief.
The only things that need connectivity are the things that actually need somewhere else to go: Amazon sync, the one-time Echoes download, iCloud propagation between devices, and Go deeper readings — which, on a device with Apple Intelligence, runs on the device itself when there is no connection.
Your library doesn't stop working because your Wi-Fi does.
The short version, again
Your books are yours. Your passages are yours. Your thoughts are yours. Refrain doesn't need to take possession of any of them to make them more interesting.
There is no Refrain cloud. There is no Refrain account. There is nothing for us to read.