MetaBook
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A book about exactly your thing, at exactly your level.

MetaBook interviews you about the topic — what you already know, what you want out of it, how deep to go — proposes a chapter outline you can rename, reorder and cut, and then writes the chapters on demand, one at a time, on your phone. And when a passage lands badly, you hold it and say simplify this — or ask for a picture of the thing it is describing. The person it is written for does not have to be you: answer the interview about somebody else and it writes them the book.

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No account. No server of ours. No analytics. Model calls go straight from your phone to your provider, billed to you — and every one of them says what it will cost before it runs.

It stops before any chapter has text, so you see the shape of the book — and what it costs — before a word is paid for.

New · version 0.6

Six things it could not do a fortnight ago.

Almost all of the recent work is in the reading loop. A passage can now be drawn as well as rewritten, a question you asked stays answered on the passage you asked it about, and everything that has ever been done to a book is one list.

Illustrate

A passage gets its picture, in place

Hold a paragraph, take Illustrate, and say what the picture should show — or say nothing and let the passage speak for itself. The reply comes back as an image, and the app writes it into the chapter as its own block directly under the passage. It is part of the book from then on: it rides inside an EPUB or an FB2 export, it returns if you restore a version that had it, and deleting it by hand costs nothing. Around 8¢ a picture, quoted high at 25¢ on the control before you press it.

Kept answers

What you asked stays with the passage

Ask was the one paid action that left nothing behind — the ledger outlived the sheet and the thing it paid for did not. Now the question and its answer are kept against the passage, the page carries a tint where you asked, and tapping it opens the answer again. The chapter's answers are a list, each with what it cost. None of it is chapter text: no byte moves, and nothing reaches an export.

Bookmarks

A folded corner, and it crosses chapters

Mark the place you are reading from the running head. The book's marks are one list in reading order, each row naming its chapter, the heading above it and the opening of the block it holds — and each is a way back into it. A mark follows its block when the text is rewritten under it, and says so plainly when the place is gone.

The inner index

A chapter's own headings are a way into it

The chapter list now opens out the chapter you are reading and lists the headings inside it, indented by level, with the one you are currently under marked. Taking one moves you there without reloading the chapter. Every other chapter keeps its single row, so opening the list parses nothing it does not already hold.

Book history

Everything done to a book, newest first

The version rows were always written, and were readable one chapter at a time. Now they are a single list for the whole book: what was done — written, rewritten, edited by hand, taken back — when it happened, the sentence you typed if you typed one, the model behind it and what the call cost. Every row leads back to the chapter it is about.

Dials

What you may say before the interview asks

Three dials on the topic screen — level, density and size — each of which may be left alone. Left alone is not a middle setting: it means ask me about this. Set one and you are shown the exact sentence it will send, and told which question you have just bought back from the interview.

And one change you see only on the bill: every task now runs on a single fast model by default, which puts an eight-chapter book in English at about 23¢ to write, cover to cover. What things cost.

The problem

Nobody has written the book you need.

A model will draft you a chapter about anything today. Turning that into a book you can sit down and read — on the right topic, at the right depth, in something that behaves like a reader — is the part nobody has done.

What it takes now

  1. Search for a book on exactly your topic.
  2. Settle for one that is half about it.
  3. Or ask a chatbot, one chapter at a time.
  4. Convert the answers to EPUB by hand.
  5. Get the file onto the phone.
  6. Read it in a separate e-reader.
  7. Hit a dense passage — copy, switch apps, ask.

Every step costs a file conversion or an app switch, so you stop asking for the book you wanted and read the one that exists.

What it takes here

  1. Say what you want a book about.
  2. Answer a few questions.
  3. Read.
  4. Hold a passage and say what is wrong with it.

One to three are the book, and they are most of the app. Four is what you do to it without ever leaving the page.

First · making a book

A topic, a short interview, and an outline you own.

The half of the app you use first, and the one that decides whether the book is worth reading at all. It stops before any chapter has text, so you see the shape of the book — and what it will cost — before a chapter is paid for.

  1. 1

    The topic, and the language

    The language a book is written in is chosen here, before the first call, and never again. It is what the interview asks in, what the outline comes back in, and what every chapter is written in. Ten to choose from.

  2. 2

    Three dials, or none new

    Level, density and size, on the same screen as the topic. Each of them may be left alone — and left alone is not a middle setting, it means ask me about this. Set one and you are shown the exact sentence it will send, and told which question you have just bought back from the interview. They freeze once a chapter has text.

  3. 3

    Three to eight questions

    What you already know, what you want out of it, how deep to go. You end the interview, from the third question on — a model that announced it had heard enough would be deciding how much more of your money to spend.

  4. 4

    An outline you can edit

    Rename, reorder, insert, remove. Editing the outline costs nothing and calls nothing — it moves titles and synopses, never text. A chapter you have not written yet says so, with its synopsis, instead of showing you a blank page.

  5. 5

    Chapters, one at a time, on demand

    A chapter takes minutes and arrives as it is written. Leave the app and it keeps going — the request is handed to the phone itself, and a notification says when the chapter is ready. Come back to an interrupted one and it continues from what you already paid for rather than starting again.

  6. 6

    The book remembers itself

    Two documents: a seed taken from your brief that no model ever rewrites, and a rolling summary refreshed as chapters are absorbed. It is why chapter nine still knows who it is written for, and does not explain chapter two again.

Nothing here is written until you ask for it, and nothing you have already paid for is thrown away. Text is saved as it arrives, so a force-quit mid-chapter costs you nothing but the rest of the chapter.

Then · while reading

Hold a passage. Say what is wrong with it.

The book is written for you, but no brief survives contact with a paragraph that is too dense. So the second half of the app is one gesture: touch and hold any paragraph and a toolbar appears — drawn by the app rather than by the phone, so it is the same on both. Four controls: Rewrite, Ask, Edit and copy. Behind Rewrite are four named actions and a field for saying it in your own words, and each of the five states what it will cost on the control you are about to press.

The passage and its two neighbours are what the model is sent. Not the chapter.
  1. 01

    Simplify

    Rewrites the passage in plainer words. You run this while reading, so it is the call the whole app is tuned for: the cheapest one it makes, and the fastest.

  2. 02

    Expand

    Rewrites the passage at greater length — for the paragraph that went past something you wanted more of.

  3. 03

    Example

    Adds a worked example to the passage. Short, concrete, and written into the book where the abstraction was.

  4. 04

    Illustrate new

    Draws the passage. Say what the picture should show, or say nothing and let the paragraph speak for itself. What comes back is an image, and the app writes it into the chapter as its own block directly under the passage — the one thing in the book the app writes and no model is ever asked for.

  5. 05

    Or say it in your own words

    A field on the same sheet. Say which years. Give this its own paragraph. This contradicts chapter two. The named actions are shortcuts for it, which is why they live behind the same door rather than beside it — and why typing in the field puts them out of reach. One instruction per call.

Ask — and now the answer is kept

Answers a question about the passage and writes nothing into the book. Asking is not editing, and one action for both would make the book unsafe to ask about. The answer is kept against the passage you asked about, the page carries a tint there, and the chapter's answers are a list — none of which is chapter text, and none of which reaches an export.

Edit — by hand, for nothing

Opens the passage's own Markdown in a field. What you type is spliced in verbatim through the same verified write a rewrite goes through, and is recorded as a version like any other change — with no call made and no cost. Emptying the field deletes the passage.

Copy — the words, not the markup

Puts the passage on the clipboard as it reads: no asterisks, no hashes, no list markers. Exactly the range you highlighted, too — not the wider span a rewrite has to take, because widening a quote would be the app editing your words.

Select more than about a third of a chapter, or use Rewrite this chapter with nothing selected, and you leave this path for a whole-chapter rewrite — roughly fifty times the cost, stated and confirmed before it runs.

In place

“The book changes in place” is a claim.
Here is what backs it.

Rewriting a passage inside a document you are holding open is the part everyone else solves by putting the answer in a side panel. Five decisions make it safe to put it in the book instead.

  1. The version is checked before the call, and again before the write.

    Offsets are computed against a particular version of a chapter. Slicing against text that has since moved would spend your money on a passage that is no longer there.

  2. The request carries the passage and its neighbours. Never the chapter.

    Two bounded slices around your selection, each snapped to a block boundary, so no request hands a model half of anything. It is what makes the call cheap enough to run casually.

  3. The reply is spliced by the app, not by the model.

    What comes back replaces exactly the range you selected, and nothing else. The model is never in a position to touch a byte outside it.

  4. Then the chapter is re-read and compared, block by block.

    Identical bytes outside the range is necessary and not sufficient: an unterminated code fence inside the replacement changes how the rest of the chapter reads without altering a byte of it. So the comparison is of the parsed document, not of the text.

  5. Undo does not rewind.

    It restores the previous text as a new version. History that ran backwards could not say what the model did, and every passage you had already selected would become ambiguous.

Nothing in the app retries a model call — a retry spends your money on the app's problem. The one thing that retries is the write.

Also · writing for somebody else

The reader in the brief does not have to be you.

The interview ends in a brief, and the brief has a section called Reader: who this book is for, what they already know, why they are reading it now. The outline and every chapter are written against it. Answer the interview about somebody else and the same app stops making you a book and starts making you an author.

You are the reader

A book for yourself

You say what you want and how much of it you already know, and the book comes back pitched at that. The four actions are how you keep it there: a chapter that lands badly is a paragraph you hold, not a book you give up on.

You are the writer

A book for somebody else

You answer the same questions about them — the new hire who starts on Monday, a student, a friend who asked what it is you actually do, a parent and their new phone. The brief describes that person, the outline is proposed for them, and every chapter is written to them rather than to nobody in particular.

  1. The brief is where you say who they are

    One call turns the interview into it, and you are shown it before an outline exists. If it describes somebody your reader is not, you say what is wrong and it is written again — one call, before a chapter has been paid for.

  2. Reading it through is the editing pass

    Same gesture, different job: simplify what will be too dense for them, expand what is too thin, add the example the abstraction needed. Ask writes nothing into the book, so you can interrogate a draft without changing it. Every version is kept — what changed it, and what it cost.

  3. Then you hand it over

    EPUB for their e-reader, Markdown for anything, FB2 — a whole book or a single chapter, out through the phone's own share sheet to wherever you send files. They need no key, no account, and no copy of MetaBook.

What leaves the phone is a file: a copy, finished at the moment you exported it. The hold-a-passage loop belongs to the app and to the device the book lives on — which is the argument for reading it through before you send it.

Money

You are spending your own money, so the app never hides it.

There is no subscription and nothing to buy from us. Every call is billed to the provider account your key belongs to, and the app is built as though you were watching the meter — because you are.

  • An estimate before, a figure after. Anything that spends says what it will cost before it runs, and what it actually cost when it is done.
  • A daily cap and a per-book budget, on by default. They refuse. There is no “continue anyway” button — raising a limit is a decision you make in Settings, deliberately, not one you make mid-flow with a chapter half-written. The defaults, $5.00 a day and $3.00 a book, are derived from what the largest book the app can produce actually costs, not guessed.
  • Every call writes a row, successful or not. The ledger is on your device and it is yours to read: what the call was for, which model, what it cost.
  • A limit is drawn as a limit. Wherever the app shows what a book has spent beside the figure it counts against, it names the second one as a ceiling you set and can move. A budget read as a price is the largest number in the flow, it arrives before the book exists, and it is wrong.
  • Prices come from the provider's live feed, and amounts are stored as whole numbers of a billionth of a dollar. Nothing is rounded into existence.
  • One model choice runs everything, and the recommendation behind it is now a single fast model for every task. The reading loop is what the product is for, so it does not get slower and dearer to buy generation quality nobody asked for. Per-task pickers are still there, behind an advanced disclosure that says whether anything is overridden without being opened.

Your key, your provider, your device

There is no backend. Not a small one — none.

No API service, no database server, no accounts, no hosting of any kind. The app on your phone talks to your model provider directly, and to nothing else. That is a decision with a cost, and it buys you this:

Your text goes to your provider, and nowhere else

What you type and what your books hold leave the device only as part of a model call, addressed to the provider your key belongs to. There is no account to make, no server of ours in the path, and no analytics anywhere in the app.

The key lives in the phone's secure storage

Keychain on iOS, Keystore on Android, and nowhere else in the app. It never reaches a log, an export, or a backup — so a backup file you hand to somebody cannot carry your key with it.

Two ways in, and you are asked which

The key screen names the provider it is about to talk to, then poses the choice as a question: connect an OpenRouter account and approve it in the browser, or paste a key you already have — with each answer saying whether it needs an account. Both take you to the same place. You can also finish setup with no key at all and read the sample book first.

The library is a file on your phone

One SQLite database — every book, every version of every chapter, the outline, the memory, the ledger. Back it up whole, restore it on the other phone, or delete all of it, key included, in one action that says exactly what it removes.

And the rest of it

The parts that make it a reader, not a demo.

Ten languages

English, German, Spanish, French, Italian, Portuguese, Russian, Turkish, Indonesian and Vietnamese — for the app, and separately for each book.

Export, losslessly

Markdown that contains each chapter's stored source byte for byte, EPUB 3 for an e-reader, and FB2 — with a picture packaged inside the last two. Exporting spends nothing and changes nothing.

Listen to a chapter

The system voice, sentence by sentence, with the phone's own play controls on the lock screen.

Mathematics, typeset

Display and inline formulae are part of what a chapter may contain — and they are drawn, not printed as dollar signs and backslashes.

Every version kept

Each chapter keeps its history — what changed, which model changed it, what it cost, what the instruction was — and the whole book's changes are one list.

Tables, ruled

A table is drawn as a grid with its header set apart, and one too wide for the page scrolls inside its own block rather than making every paragraph around it harder to read.

Six levels of heading

Below level three a heading gets quieter rather than smaller: under the body size a heading stops reading as a heading and starts reading as a caption.

A sample already on the shelf

The app seeds one book and marks it as its own, so there is something real to read — formulae, tables and all — before you have a key.

The place you stopped

Reading position is an offset into the chapter's own text, not a scroll position, so it survives the text being rewritten under it.

Paper and night

A reading theme that is designed rather than inverted, with the app around it built from the same palette.

Nothing is lost to a kill

Text is written down as it arrives. Force-quit the app mid-chapter and you come back to everything you had already paid for.

The same on both phones

One codebase, and a rule that a feature exists on both targets or on neither. The selection toolbar is the app's own, so it behaves identically on each.

Before you download it

What it does not do.

  • It needs an API key. MetaBook has no server and sells you nothing, which means it cannot pay for your generation. You bring an OpenRouter account — connecting one takes a couple of taps — and the bill is yours. Without a key you can look around and read the sample book the app seeds, but nothing new is written.
  • The chapters are written by a language model, and checked by nobody. A model states wrong things as confidently as right ones. A book here is a good starting point and a bad citation.
  • No fiction. This is for non-fiction and for learning. Novels are a different job and it does not do that job.
  • Phones only. Android and iOS. There is no web version and no desktop one.
  • No accounts, so no sync. Your library lives on one device. Moving it to another is a backup file you carry across yourself.
  • A book you write for somebody else leaves as a file. Export it and they read it in whatever opens an EPUB. There is no way to hand somebody a book that is still live — the reading actions need the app, a key of their own, and the book on the device it was made on.

Ask for the book you wanted.
Then change it as you read.

Free to install. What you spend is what your provider charges, and the app tells you before you spend it.

Download on theApp Store Get it onGoogle Play