Frequently asked questions

No. Your PDFs live on your device, and — if you turn sync on — in your own iCloud account. There is no Fihris server that stores or serves papers, and there never will be: arXiv's terms do not permit it, and the app is built so it cannot happen.

The one server Fihris runs is the Fihris Intelligence relay, and it never receives a PDF or a whole paper. When you ask a question on that route it receives your question and the short passages that Fihris's on-device search already picked out as relevant — nothing else. Fihris's relay keeps nothing: no question, excerpt or answer is stored there. It forwards them to Anthropic to generate the answer, and what Anthropic does with what it is sent is covered by Anthropic's own privacy policy and terms — Anthropic's default retention for API requests is 7 days, and we do not claim otherwise. The privacy policy sets out both sides in full.

Fihris always uses the smallest route that fits your question, and tells you which one before it sends anything.

1. On this device. Apple's on-device model. Nothing leaves your device. Free, offline.
2. Apple's private cloud. Apple's Private Cloud Compute, where your device supports it. Inside Apple's privacy boundary; Apple retains nothing; free.
3. Fihris Intelligence. Our relay, which forwards to Anthropic's Claude. Optional, paid, and gated behind a consent card that names both the relay and Anthropic.
4. Your own Claude or ChatGPT account. Only if you connect your own key. Straight from your device to that provider; your account pays.

You can see and change the order in Settings ▸ AI ▸ Where answers run, and you can always decline a route and take a smaller one instead.

Fihris Intelligence is an optional subscription that answers your bigger questions through a server we run, on Anthropic's Claude — the ones that are too large for the model on your device and that you would otherwise need your own API key for.

$10.99 a month or $99.99 a year, with a 7-day free trial. Other storefronts are priced by Apple in the local equivalent. It includes 300 credits a month, and a 150-credit top-up is $4.99 if you need more. Full detail is on the subscription page.

You do not need it. Everything else in Fihris — including grounded questions, the literature matrix, gap finding and cite-while-writing — works for free on your device, on Apple's private cloud, or on your own key.

The unit Fihris Intelligence is metered in. Each kind of action costs a fixed number of credits: a grounded question is cheap, a literature matrix over forty papers is not. The full table is in the app before you subscribe and in Settings ▸ AI.

The monthly allowance of 300 credits resets at each renewal and does not roll over. Credits from a top-up never expire and are spent only after the allowance runs out. A request that is refused or that fails on our side is not charged.

Yes, and it stays free. Paste an Anthropic or OpenAI key in Settings ▸ AI and Fihris will use your account instead of ours. The key is stored in the iOS Keychain on your device, never in a file, never in a backup we can read, and never sent anywhere but that provider.

If you have both a key and a subscription, Settings ▸ AI ▸ When both are available decides which one wins. The default is Fihris Intelligence; switch it to your key whenever you like.

Your own key also unlocks the highest-fidelity citation mode, where Anthropic's API extracts the cited passage and page itself from a whole paper. That mode is deliberately never routed through our relay, because the relay never receives whole papers.

A one-time purchase — $22.99, not a subscription — that unlocks iCloud sync, mind maps, analysis, manuscripts and Export everything.

Fihris Pro never gates AI. The two purchases are separate on purpose: Pro buys features in the local app forever, Fihris Intelligence pays for inference on somebody else's computer.

Mostly, yes, and by design. In airplane mode you can read, highlight, underline, draw with Apple Pencil, write and link notes, browse and organise your Library, search it, open a mind map or an analysis you have already built, write in the LaTeX editor with the cite picker, and ask questions answered by the model on your device.

What needs a connection: Discover (it queries live sources), Apple's private cloud, Fihris Intelligence, your own key, and iCloud sync.

One honest caveat: this version has no on-device TeX engine, so there is no offline "compile to PDF". You get the editor, the cite picker, a structural preview, export, and a one-tap hand-off to Overleaf.

If you asked Fihris Intelligence something it judged to be outside its job, it replies with one sentence:

I can only help with questions about the papers in your library.

Fihris Intelligence answers questions about the papers in your Library. It is not a general-purpose chat service and will decline other requests: it will not write code, hold an unrelated conversation, or do work that has nothing to do with the papers you gave it. That is a deliberate limit, it keeps the price where it is, and a refused request is never charged.

The check is not perfect. If a genuine research question was refused, please tell us — we cannot see your question, so a report from you is the only way that gets fixed.

Refusals can also come from a different place: if the model declines on its own safety grounds, you see the same sentence, and again you are not charged.

Every iPhone and iPad running iOS or iPadOS 18 or later. It is one universal app: the phone is not a cut-down version, it is the same app laid out for a smaller screen. Apple Pencil support on iPad is the one honest hardware difference.

Answering on your device needs a recent iOS and an Apple Intelligence-capable device. If yours does not have it, nothing is unreachable — those questions route to Apple's private cloud, to Fihris Intelligence, or to your own key, and Fihris says which.

Not today. Fihris is a universal iPhone and iPad app.

A Mac version is intended and the app is built to make it cheap — SwiftUI throughout, with the iOS-only pieces behind thin wrappers — but it is not released and has no date. There is no Android version and none is planned; too much of Fihris is built directly on Apple's frameworks.

Discover searches several scholarly sources at once and merges the results: arXiv, OpenAlex, Crossref, Semantic Scholar, DBLP, CORE and Unpaywall. You can also connect a Springer Nature account for full-text access you already have.

If one source is slow or down, Fihris degrades that source and still shows you the rest.

Yes, and it is one of the reasons the architecture looks the way it does.

• arXiv is queried at one request every three seconds, on a single connection — its published limit. A rate-limited search is slower on purpose.
• OpenAlex and Unpaywall get a contact email, as their polite-pool rules ask.
• A PDF is downloaded straight from the source to your device. Fihris never stores or re-serves an e-print, which arXiv's terms forbid, and the relay never fetches from arXiv or a publisher at all — it can reach exactly one host, and that is checked by its own tests.
• Access you get through a publisher account is your access, used on your device with your credentials.

Yes, and this is the part of Fihris worth understanding.

Fihris chops up every PDF itself, so it owns the map from each passage to its paper, page and character range. When a model answers, it is given numbered passages and is asked to cite them by number — it is never asked for, and never allowed to write, a page number. Fihris resolves those numbers to pages from its own index.

So the page pointer cannot be hallucinated. A number the model invents resolves to nothing and never becomes a citation. What can still be wrong is the choice of passage — and because every citation is a chip you tap to open the paper at that page with the passage highlighted, you can check it in a second. Do check it.

If you turn it on, and if you have Fihris Pro. Sync uses your own iCloud account — a private CloudKit database and container that belongs to you. We cannot read it; Apple's private database is inaccessible to developers by design.

It is off by default. Turning it off and choosing to remove the Library from iCloud takes it back out of your container. Derived data — the search index and the embeddings — is never synced; it is rebuilt on each device and kept out of your iCloud backup so it does not eat your storage.

Per paper or per collection: BibTeX, RIS, CSL-JSON, a Markdown file of your notes and highlights, an annotated copy of the PDF with your markup burned in, and the original PDF.

A mind map exports as PDF, a Markdown outline, OPML, GraphML or DOT.

Export everything (Fihris Pro) writes your whole Library — papers, PDFs, annotations, notes and drafts — into a single archive, so you are never locked in. Fihris stores metadata in the CSL-JSON shape the rest of the reference-manager world uses, which is why moving in and out is boring rather than painful.

No. There is no account, no password, no profile, and no email address collected. Your purchases travel with your Apple Account through the App Store; Restore purchases brings them back on a new device.

The trade-off: if you ever need us to find your subscription — for support, a data request or a deletion — the only handle we have is your App Store transaction identifier. It is in Apple's confirmation email and in Settings ▸ AI ▸ Fihris Intelligence.

An audit log, kept on your device, of every question that was answered anywhere other than on your device. Each entry records which route was used, the titles of the papers involved, how many pages and passages, and token counts.

It never records the question or the answer — the log must not become a second copy of your research. Nothing in it is ever uploaded. You can read it, and clear it, in Settings ▸ AI ▸ Sent to your account.

Cancel through Apple: Settings ▸ your name ▸ Subscriptions ▸ Fihris Intelligence ▸ Cancel subscription. It takes effect at the end of the period you have paid for. Refunds are Apple's, at reportaproblem.apple.com.

Afterwards, nothing is taken away. Your Library, annotations, notes, mind maps and drafts are local and untouched, and Fihris keeps answering questions on your device, on Apple's private cloud, and with your own key. Only the relay route stops. Top-up credits stay in your balance for if you come back.

On the App Store, in the storefronts listed on the press page. Fihris is currently not offered in the 27 European Union storefronts — a decision about the EU's trader-disclosure rules that we would rather make properly than quickly. It may change; the App Store listing is always the current answer.

Fihris (فهرس) is Arabic for index or catalogue. It is pronounced FIH-ris.

It is a nod to Ibn al-Nadim al-Warrāq's Kitab al-Fihrist of 987 CE — a catalogue of some 4,300 authors and the books they wrote, and arguably the first reference manager anyone built. Naming a reference manager after it seemed only fair.