It's not what's in your pocket.
It's what's in your head, and Rex is here to help you fill it.
On iPhone, iPad and Mac. One account, the same boards on all of them.
You can't buy a crown. You earn it. Rex is here to help you earn yours.
And because we believe anyone should have access to great learning tools, Rex starts free. No paywalls on the basics. You show up. Rex shows up for you.
What's inside
Built to help you actually understand, not just memorize.
Ask anything. Get real explanations and step-by-step walkthroughs across every subject, from math and science to history and coding.
Organize notes, charts and ideas on infinite canvases. Everything syncs, so your study session is waiting where you left it.
Type an equation and Rex solves, differentiates, integrates, factors and simplifies it exactly, then writes the working out line by line. Tap a line you do not follow and he explains that step. The algebra runs on your device, so the answer is right whether or not you have a signal.
Turn a board, a chapter or a recorded lecture into flashcards, then let Rex schedule them. Cards you find easy disappear for weeks. Cards you keep missing come back in minutes. Your progress follows the card, across every deck and every device you sign in on.
Small learning widgets you poke at instead of read. Build your own, publish them, or remix someone else's.
Work it out by hand, with layers, real brushes and a panel built for thinking on paper. Rex can mark up your drawing the way a teacher would, pointing at the line where it went wrong instead of just telling you it did.
Record the lecture and get the transcript. Transcription runs on your device wherever the language allows it, so the recording is yours.
A browser that lives beside your work, with SafeSearch locked on and ads and trackers blocked. Look it up without losing your place.
Talk to Rex and he talks back, hands free. He works on your board while he explains, then shrinks to a corner so the board has the screen. You decide whether he's allowed to touch it.
Rex reads it out in his own voice and highlights the sentence he is on, scrolling the page to keep up with himself: a web page, a PDF, an EPUB, your notes, even a photo of a worksheet. The voice runs on your device, and there is no cap on how much of it you use.
Search actual published papers from your board and keep the ones that matter beside your notes, so a claim in an essay can point at something real.
Drop in a PDF, a file, or a photo of the worksheet and scan it straight onto the board. Whatever you're studying from can sit next to the work instead of in another app.
Open an EPUB beside your work, keep your place in it, and hand it to read aloud like anything else. The book, your notes about the book and the questions you asked about it all live on the same board.
Make one link to one board and give it to ChatGPT, Claude or whatever you already use. It can read the board and fix your wording, add notes or build a teaching chart on it. It cannot touch anything else you own, every change it makes is logged, and you can kill the link in a tap.
Boards, drawings, the solver, read aloud and transcription all keep working with no connection. Rex writes to your device first and syncs when the signal comes back, so a bad train ride costs you nothing.
One reminder a day, at the time you pick, and a streak that only counts the days you actually showed up. Home tells you how many cards are ready before you have to go looking for them.
The Rexer
Live nowEverything you put on a board is material. The Rexer turns that pile into a taught lesson, out loud, one thing at a time, on the board you already built.
It sits on the same button you add widgets with. Nothing to set up, nothing to export, no render to wait through.
Your notes, PDFs, scans, drawings, charts, the pages you kept and the lecture you recorded. Each one is read in full rather than skimmed, so a big board gets taught, not summarised.
Everything goes dark and Rex lights up one item at a time, talking over it in his own voice, with captions, a running order you can jump around in, and a way to stop and ask him about the thing on screen.
Stop him mid-sentence and ask for that part again another way. The lecture leaves things behind on the board as it goes, and the end card shows what it was built from: how many stops came from your own work, how many from your recording, and how many Rex added where your notes stopped. Save the whole thing as a video or send it to someone.
The Rexer never invents your lesson. It teaches what is on the board, in the order the board suggests, weighted by what you actually spent the session on. So the way to get a better lecture is not a better prompt. It's a better board.
Six things that change the result.
Every stop is labelled with where it came from: your notepad, your recording, or Rex filling a gap. And if you're offline, out of your daily allowance, or on a board Rex can't make sense of, you still get something: he reads the board back to you in its own words, marked as a read through, so a read through is never passed off as a lecture.
Playground
A chart can be a 3D scene you turn in your hands, a language drill, or a study set. These are real ones from Rex, running the way they run in the app. Try them, then load a file of your own to test it before you ever publish.
Load your own file to check it against the same lint the app runs on import, and to try its variables before you publish. Nothing is uploaded. It stays in your browser. Writing one with an AI assistant? Hand it the chart guide, which spells out the rules and the variable contract it has to follow.
These are the variables your file exposes. Change one and the preview re-runs, which is what happens when someone remixes your chart in the app.
How it works
You don't need a tutor's schedule or a permission slip. You need a phone and ten minutes.
Free on iPhone, iPad and Mac. No credit card, no trial countdown, nothing to cancel later.
Type it, say it, or put your notes on a board. Rex explains it in steps until it clicks.
Turn the answer into a chart, a quiz or a sketch, then come back and beat it tomorrow.
Plans
Every plan has every tool. Nothing is locked away behind a tier. What changes is how much you can ask the tutor each day.
Free
$0/mo
Every tool, a real daily allowance. No credit card, no trial timer.
Most popular
Pro
$12.99/mo
The largest daily allowance, and open to anyone. One plan, no tiers to qualify for.
Best value
Pro Annual
$99.99/yr
The same Pro plan, billed once a year instead of every month.
Prices are US dollars and renew monthly or annually through the App Store. Cancel anytime in your Apple ID settings. Running out of tokens pauses the tutor until the next day; it never touches your boards, notes or recordings.
Questions
The stuff people ask before they download.
Yes. The tutor, study boards, whiteboard, notes, charts and read aloud are all on the free plan, with no credit card and no trial timer. Paid plans add capacity and advanced tools. They don't unlock the basics.
iPhone, iPad and Mac. It is one account and one set of boards across all three, and your flashcard schedule follows you between them, so you can start a review on your phone and finish it on the Mac.
Read aloud and dictation both run on your device, and dictation audio is discarded the moment it becomes text. A recording you deliberately save is different: it is a file you are keeping, so the transcript syncs to your account and the audio stays on your device unless you choose to upload it. The full detail is in our privacy policy.
You can. Build one in the app with quiz modes or Frame Studio, or import your own self-contained HTML file. The full guide and starter template are in the chart docs.
It plays your board back to you as a spoken lecture. Rex reads everything on the board, your notes, PDFs, scans, drawings, charts and any lecture you recorded there, then darkens the board and lights up one item at a time while he teaches it. You can jump around the running order, stop him mid-sentence and ask about whatever is on screen, and save the whole thing as a video at the end. The lecture also leaves notes behind on the board as it teaches. Every stop says where it came from, so you can always tell your own work from the parts Rex filled in. It is live now.
Give it a better board. It teaches what is actually there, in the order the board suggests, and it gives more time to the things you spent the session in. So: keep one board per lesson, lay it out in reading order, write your notes in your own words, and record the class on the board when you can. A recording becomes the spine of the lecture, so it follows the order the class was taught in rather than the order tiles landed on the canvas.
It does it. The solver takes an equation and solves, differentiates, integrates, factors and simplifies it exactly, then shows the working line by line so you can see where a step came from. Tap a line and Rex explains that step on its own. The algebra itself runs on your device rather than on a server, which is why it still works with no signal and why it does not guess.
By how well you actually knew it. Answer a card easily and it goes away for weeks; miss it and it comes back in minutes, then a day, then longer as it sticks. The schedule belongs to the card, not the deck, so meeting the same idea somewhere else picks up where you left off, and it follows your account onto your other devices.
Yes. From Share Board you can mint one link to one board and hand it to any AI that can open a URL. It can read that board and do a short list of things to it: fix the wording of what is there, add notes, and build a teaching chart, a quiz or a set of flashcards. It cannot see your other boards, cannot delete anything, cannot touch your drawings or files, and cannot publish to the chart store. Every read and write is logged for you, the link expires on its own, and you can rotate or revoke it whenever you want.
Most of it. Boards, notes, drawings, the solver, read aloud and transcription all keep working with no connection, because they run on the device. Rex saves your work locally first and syncs when the signal comes back. The tutor itself needs a connection, since that is a model answering you.
A hands free conversation with Rex. You talk, he answers out loud, and he can work on your board while he explains, pulling up a chart or writing something down as he talks. When he touches the board he steps aside so you can see it, and shrinks to a chip in the corner. Whether he is allowed to change the board is a switch you control, and you can end the session at any time.
Yes. Read aloud handles web pages, PDFs, your own notes, and images, including a photo of a worksheet or a scanned page, by reading the text out of the picture first. Rex highlights the sentence he is on as he goes, and the voice is generated on your device.
Nothing except how you pay. Pro is $12.99 a month, or $99.99 for a full year billed once. Both plans include every tool and the same 300,000 daily tutor tokens.
No. There are three plans and that is all of them: Free, Pro at $12.99 a month, and Pro Annual at $99.99 a year. There is no student tier, no school email to verify and nothing to apply for. Pro is the same price for everybody, and the free plan is a real plan rather than a trial.
Tokens are how the tutor's usage is measured: roughly speaking, a token is about three quarters of a word, counting both your question and Rex's answer. Free gets 50,000 a day, Pro 300,000, and the count resets every day. Most study sessions do not come close. If you do run out, the tutor pauses until tomorrow and everything else in Rex keeps working.
Yes. You can connect your own OpenRouter account, and the tutor will answer through a model you choose and pay for instead of Rex's, without passing through our servers. Free models are available there, so it is a way to keep going past the daily allowance without a Rex subscription.
Your boards, notes and recordings stay exactly where they are. You drop back to the free plan's daily allowance, but nothing is deleted for cancelling.
The basics are always open, for every student, no matter what's in their pocket. Anyone can start.
Start free on the App Store