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How to read and watch with instant tap-to-translate

CIRCØ is a free, private, browser-based reader and video player with instant tap-to-translate built in. Read EPUB books, PDF documents, and CBZ/CBR comics, or watch videos with subtitles — and tap any word to translate it. There is no account and no install: your library and progress stay in your browser, and only the text you choose to translate is sent off-device.

Getting started

1. Open circ0.com in any modern browser (desktop or mobile).
2. Upload a book or a movie — EPUB, PDF, CBZ, CBR, or a video file (MP4, MKV, MOV, WEBM, AVI, FLV).
3. Choose your From and To languages in the header.
4. Tap a word or select text to translate it (the exact gesture depends on the format — see below).

Translating EPUB books

Open an EPUB and read in paginated mode with previous/next navigation, light or dark theme, and adjustable font size and line spacing. To translate, tap any word or select a phrase or sentence. A popover shows the translation instantly, and translated words are highlighted and saved per book so you can review them later.

Translating PDF documents

PDFs render with a transparent text layer for native text selection. Select any word or phrase on the page to translate it. You can fit-width, fit-page, or zoom to 150%, and navigate pages with the arrow keys.

Translating comics and manga (CBZ/CBR)

Comics are images, so translation uses OCR (optical character recognition):

1. Set your From and To languages.
2. Click the translate icon in the toolbar — the cursor becomes a crosshair.
3. Draw a rectangle over any text in the comic.
4. OCR reads the text in that region, then it is translated and shown in a popover.

OCR supports English, Spanish, French, German, Italian, Portuguese, Russian, Japanese, and Chinese (Simplified). Reading direction can be set to left-to-right or right-to-left for manga.

Translating video subtitles

The built-in video player supports local video files, multi-track audio, external audio uploads, embedded subtitle extraction, sidecar SRT/VTT uploads, and subtitle timing shift. With subtitles showing, tap a subtitle word or select a phrase to translate it on the fly — great for language learning while watching films and shows.

Translating fully offline with on-device AI

On capable devices — desktop computers and most Android phones — CIRCØ can translate with no internet connection at all. Open Settings and enable Offline AI Translation to download an on-device neural translation model (about 900 MB, once). It covers 200+ languages, runs entirely on your device, and never sends tapped text anywhere. iPhones and very low-memory phones stay on fast online translation instead — the app tells you which mode your device supports.

Why CIRCØ for language learning

• Read or watch in your target language and translate only the words you don't know.
• Private by design — your library, reading position, highlights, and history stay in your browser.
• No account, no install, no cost.
• Installable PWA that works offline after the first load.
• One app for everything — books, documents, comics, and videos.

Questions? Email circ0@circ0.com. See our privacy policy and terms of use.