
Readest
Readest is a free, open-source ebook reader for EPUB and PDF, with support for formats including MOBI, AZW3, FB2, CBZ, and TXT.
What Readest is
Readest is a free, open-source ebook reader for EPUB and PDF, with support for formats including MOBI, AZW3, FB2, CBZ, and TXT. Readers can highlight passages, bookmark pages, take notes, and search their ebook libraries. Its Parallel Read feature displays two books together with synchronized scrolling and navigation. The reader can translate passages, look up words in Wiktionary or Wikipedia, and read books aloud through on-device, browser, or cloud text-to-speech. It connects to OPDS catalogs and calibre libraries, and can export highlights to Readwise or Hardcover. Screen readers are supported. Books, notes, highlights, and bookmarks stay on the device by default; optional syncing can use WebDAV, Google Drive, OneDrive, iCloud Drive, or S3-compatible storage. Third-party cloud sync requires a paid plan. The free plan lists 500 MB of cloud storage and 10K AI translation characters per day. Plus costs $4.99 per month and includes 5 GB of sync storage, 100K daily AI translation characters, and unlimited AI read-aloud hours. Readest is available on Android, iOS, Linux, macOS, Windows, and the web.
Good
- Supports EPUB, PDF, MOBI, AZW3, and other formats.
- Parallel Read synchronizes two books.
- Screen readers are supported.
- Books and notes are stored locally by default.
Watch out
- Third-party cloud syncing requires a paid plan.
- Free cloud storage is limited to 500 MB.
Who it suits
Readest suits readers who want annotation, lookup, translation, or text-to-speech alongside ebook reading. Its side-by-side mode may appeal to people reading two books in parallel.
Verdict
Readest combines broad file support with annotation, lookup, and listening tools across desktop, mobile, and web. Consider its free storage limit if you need cloud syncing.
Plans and prices
From Readest's own pricing page, checked 14 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free Plan | Free | 500 MB cloud storage · 10K AI translation characters/day · AI read aloud · basic customization · community support · $0.00/month |
| Plus Plan | $4.99 a month | 5 GB cloud storage · 100K AI translation characters/day · unlimited AI read-aloud hours · DeepL Pro · full customization · priority support · $4.99/month |
| Pro Plan | $9.99 a month | 20 GB cloud storage · 500K AI translation characters/day · all Plus benefits · early feature access · advanced AI tools · $9.99/month |
| Lifetime storage 1 GB | $9.99, paid once | Adds 1 GB cloud storage permanently · One-time payment |
| Lifetime storage 2 GB | $14.99, paid once | Adds 2 GB cloud storage permanently · One-time payment |
| Full Customization | $19.99, paid once | Own-cloud sync · Send to Readest email · offline read-aloud downloads · Audiobookshelf offline downloads · trusted-device BookDrop · One-time payment |
| Lifetime storage 5 GB | $29.99, paid once | Adds 5 GB cloud storage permanently · One-time payment |
| Lifetime storage 10 GB | $49.99, paid once | Adds 10 GB cloud storage permanently · One-time payment |
| Lifetime Plan | — | 1 GB $9.99 · 2 GB $14.99 · 5 GB $29.99 · 10 GB $49.99 · Full Customization $19.99 · One-Time Payment |
The facts
Each one read from Readest's own pages, with the date it was checked.
What it does
- Accessibility
- The download page says Readest supports screen readers for visually impaired users.checked 29 Sep 2026
- Account and sync limits
- The pricing FAQ says books already in Readest Cloud remain downloadable after downgrading, but uploads above the free 500 MB limit and third-party cloud syncing pause.checked 29 Sep 2026
- Annotations
- The app provides highlights, bookmarks, structured notes, deep links to passages and annotation export.checked 14 Oct 2026
- API and extensibility
- The latest release adds support for connecting a user-supplied OpenAI-compatible voice service.checked 14 Oct 2026
- Catalogs and library tools
- Readest connects to OPDS catalogs and calibre libraries, and supports exporting highlights to Readwise or Hardcover.checked 29 Sep 2026
- Cloud integrations
- Sync options include Readest Cloud, WebDAV, Google Drive, OneDrive, iCloud Drive and S3-compatible storage.checked 14 Oct 2026
- Documentation depth
- Official documentation covers installation, formats, reading, library management, customization, sync, listening and troubleshooting.checked 14 Oct 2026
- File formats
- Readest supports EPUB, PDF, MOBI, AZW3, FB2, CBZ, and TXT files.checked 29 Sep 2026
- Latest release
- GitHub lists Readest 0.12.16 released on October 13, 2026, with new premium voices, handwriting annotations, quote-card sharing and sync fixes.checked 14 Oct 2026
- Library integration
- Readest connects to OPDS catalogs, Calibre and Calibre-Web, including covers and metadata.checked 14 Oct 2026
- License
- The source repository licenses Readest under the GNU Affero General Public License version 3 or later.checked 14 Oct 2026
- Limit: bulk tagging
- A Google Play reviewer says adding tags to multiple books at once is missing.checked 14 Oct 2026
- Limit: contributor complexity
- An independent technical review measured 1,652 packages, 1.8 GB of dependencies and 46 failing tests in its test run.checked 14 Oct 2026
- Limit: no bookstore or DRM ecosystem
- An independent review says Readest is not a Kindle, Kobo or Apple Books store client and should not be treated as a DRM replacement.checked 14 Oct 2026
- Limit: PDF specialization
- An independent review warns that fixed-layout and scanned PDFs may not provide EPUB-level reflow, selection, translation or text-to-speech behavior.checked 14 Oct 2026
- Limit: pre-1.0 maturity
- The same technical review describes the project as pre-1.0 and advises validating the exact formats, sync paths and accessibility features required.checked 14 Oct 2026
- Limit: text-to-speech reliability
- A Google Play reviewer reports that TTS stopped at random sentences and sometimes required restarting the app or phone.checked 14 Oct 2026
- News: secure open-source fund
- Readest announced participation in the GitHub Secure Open Source Fund on August 29, 2026, covering threat modeling, code scanning and incident response work.checked 14 Oct 2026
- Open source
- Readest says its free software is open source under the AGPL-3.0 license.checked 29 Sep 2026
- Parallel reading
- Parallel Read displays two books or documents side by side with synchronized scrolling and navigation.checked 14 Oct 2026
The company
- Legal maker
- Readest’s website copyright and Google Play developer information identify Bilingify LLC.checked 14 Oct 2026
- Maker founders
- The project blog identifies Huang Xin and Hou Qingping as the people who started Readest.checked 14 Oct 2026
- Maker headquarters
- Google Play lists Bilingify LLC at 30 N Gould St Ste R, Sheridan, Wyoming 82801-6317, United States.checked 14 Oct 2026
- Maker origin
- The project says Readest began in the Berlin State Library, where its first code was written.checked 14 Oct 2026
The full review of Readest
Overview
Readest is an open-source reader for ebooks and PDFs, suited to readers who want annotation, lookup and listening tools without tying their library to one device. Its broad format support and offline reading make it a capable everyday reader; cloud syncing is the main feature to budget for.
Readest supports EPUB, PDF, MOBI, AZW, AZW3, FB2, CBZ, ZIP, TXT and Markdown. Readers can highlight, bookmark, take notes and search their library, while connections to OPDS catalogs and calibre libraries help bring books from different collections into one place. It is licensed under AGPL-3.0.
Ebooks, notes, highlights and bookmarks stay local by default and are not uploaded without an explicit action such as enabling sync. Readest says it encrypts sensitive data and follows secure app-code practices, while acknowledging that no electronic storage or transmission method is completely secure.
For more options, see our Ebook Reader Software guide.
Key features
- Annotation and search: Highlights, bookmarks and notes let readers mark up books, and library search helps find a passage without browsing titles one by one.
- Parallel reading: Two books can appear side by side with synchronized scrolling and navigation, useful for comparing texts or following a translation.
- Translation and lookup: Readers can translate passages or consult Wiktionary and Wikipedia for a word. Google, Azure and DeepL are translation providers; daily AI translation allowances depend on the plan.
- Text to speech: Books can be read aloud using on-device, browser or cloud speech, offering a listening option as well as support for screen readers.
- Catalogs and exports: OPDS and calibre connections support access to external libraries, while highlights can be exported to Readwise or Hardcover.
- Cloud sync: WebDAV, Google Drive, OneDrive, iCloud Drive and S3-compatible storage are supported, but third-party cloud sync requires a paid plan.
Pricing
Readest uses a freemium model. The Free Plan includes 500 MB of cloud storage and 10K AI translation characters per day, enough for a small synced library but a tight ceiling for readers who upload many books.
The Plus Plan costs $4.99 a month and provides 5 GB of cloud sync storage, 100K AI translation characters per day and unlimited AI read-aloud hours. It is the paid entry point for readers who need third-party cloud sync or want substantially more translation capacity.
The Pro Plan costs $9.99 a month, raising storage to 20 GB and translation to 500K characters per day. It suits larger synced libraries and frequent translation use; the listed plan does not include a separate AI read-aloud allowance.
Lifetime options are billed as a one-time payment: 1 GB for $9.99, 2 GB for $14.99, 5 GB for $29.99, 10 GB for $49.99, or Full Customization for $19.99. These are alternatives for readers who prefer a one-time purchase over a monthly plan, though storage is capped at the selected tier. The Full Customization option is named but has no further included features specified.
After downgrading, books already in Readest Cloud remain downloadable, but uploads above the free 500 MB limit and third-party cloud syncing pause. Free and paid users can seek support through documentation, community channels, GitHub issues and support email.
Platforms
Readest runs on the web, Windows, macOS, Linux, iOS and Android. Offline reading and broad file support make it practical for a library that includes both local files and cloud-synced books, while screen-reader support extends access for visually impaired readers.
Who it's for
Readest is a strong fit for readers who manage books in several formats, annotate frequently, consult reference sources, or want parallel reading and text to speech in the same app. Its local-first defaults also suit readers who prefer not to upload a library unless they choose to sync it.
It is less compelling for someone who needs generous cloud storage without paying: the free allowance is 500 MB, and third-party sync is paid. Readers who keep books only on one device can still use the reader and its local tools without relying on cloud storage.
Pros and cons
- Pro: Support for EPUB, PDF, MOBI, AZW3, CBZ and other formats reduces the need to convert a mixed ebook collection.
- Pro: Notes, highlights, lookup, translation and synchronized two-book reading address more than basic page turning.
- Pro: Local storage by default gives readers control over whether books and annotations are uploaded.
- Con: Free cloud storage stops at 500 MB, and third-party cloud sync requires a paid plan.
- Con: Translation quotas differ sharply by tier, so frequent users may need the $9.99-per-month Pro plan rather than the free allowance.
Alternatives
For a wider comparison, browse Ebook Reader Software.
- Libby is a better fit for readers who want to borrow digital content for free with a valid library card and avoid subscription costs.
- Adobe Digital Editions is another free reader option.
- Thorium Reader is a free alternative for readers using iOS, Linux, macOS or Windows.
- eBoox offers a free, ad-free plan on Android, iOS and the web.
- ReadEra has a free, ad-free plan with no registration; its one-time $14.99 Premium plan includes Google Drive sync, background text to speech and quotes.
- Kobo Books is an alternative for readers considering a catalog-oriented service, with Kobo Plus Listen at $7.99 per month after a 14-day free trial.
- PocketBook Reader is a free reader app for Android and iOS.
- DinoReader is a free Android ebook reader with no subscription.
Verdict
Choose Readest if you want a flexible reader for varied file formats, with annotation, parallel reading, lookup and speech tools across desktop, mobile and web. Its local-first approach and library connections are persuasive strengths. Look elsewhere if your priority is generous cloud storage at no cost: Readest's 500 MB free cap and paid third-party sync make that the clearest trade-off.
Getting started
- Open the Readest website or use Readest on Windows, macOS, Linux, iOS, or Android.
- Open supported ebook or PDF files in Readest.
- Use the free plan, which includes 500 MB of cloud sync storage and 10K AI translation characters per day.
- Choose a paid plan for third-party cloud syncing or higher listed plan limits.
Limits worth knowing
The free plan includes 500 MB of cloud sync storage and 10K AI translation characters per day. After downgrading, books already in Readest Cloud remain downloadable, but uploads above the free storage limit and third-party cloud syncing pause.
Questions
Is Readest free?
Yes. The Free plan has no listed price and includes 500 MB of cloud sync storage and 10K AI translation characters per day.
Which platforms does Readest support?
Readest is available on the web, Windows, macOS, Linux, iOS, and Android.
Is Readest open source?
Yes. Its free software is open source under the AGPL-3.0 license.
Which file formats can it read?
Supported formats include EPUB, PDF, MOBI, AZW, AZW3, FB2, CBZ, ZIP, TXT, and Markdown.
Does Readest sync across cloud services?
Its sync guide lists WebDAV, Google Drive, OneDrive, iCloud Drive, and S3-compatible storage. Third-party cloud syncing requires a paid plan.
What are the paid plans?
Plus costs $4.99 per month and includes 5 GB of cloud sync storage, 100K AI translation characters per day, and unlimited AI read-aloud hours. Pro costs $9.99 per month and includes 20 GB of cloud sync storage and 500K AI translation characters per day.
Alternatives to Readest
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ReadEra
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