Readest

Readest is a free, open-source reader for ebooks and PDFs, with tools for annotation, lookup, translation, and listening. It supports EPUB, PDF, MOBI, AZW3, FB2, CBZ, and TXT files, among other listed formats. Readers can highlight passages, bookmark pages, take notes, and search their library. Parallel Read places two books side by side with synchronized scrolling and navigation. Readers can translate passages, look up words in Wiktionary or Wikipedia, and listen through on-device, browser, or cloud text-to-speech. The app connects to OPDS catalogs and calibre libraries, and can export highlights to Readwise or Hardcover. Screen readers are supported, and the software is open source under the AGPL-3.0 license. Books and reading notes are stored locally by default; cloud syncing with third-party services requires a paid plan. Readest runs on Android, iOS, Linux, macOS, Windows, and the web. The free plan lists 500 MB of cloud storage; Plus costs $4.99 a month.

Readest combines a broad format list with annotation, lookup, and listening tools. Its free plan includes cloud storage, while third-party cloud sync requires a paid plan.

Readest may suit readers who want ebook annotation, parallel reading, lookup, translation, or text-to-speech across desktop, mobile, and web. Screen reader support is listed for visually impaired users.

Readest is an ebook and PDF reader for people who want annotation, lookup and listening tools alongside a broad range of file formats. Its strongest case is cross-platform reading with library connections and optional cloud sync; readers who need more than the free storage and translation allowances will need to weigh the monthly plans.

Overview

Readest handles EPUB, PDF, MOBI, AZW, AZW3, FB2, CBZ, ZIP, TXT and Markdown files, and supports offline reading. Highlights, bookmarks, notes and library-wide search make it useful for readers who do more than read straight through. The ability to display two books side by side with synchronized scrolling and navigation is a more specialized benefit for comparing texts or keeping reference material open.

Readers can translate passages, consult Wiktionary or Wikipedia, and hear books through on-device, browser or cloud text-to-speech. Readest also connects to OPDS catalogs and calibre libraries, and can export highlights to Readwise or Hardcover. Taken together, those tools suit readers with books spread across sources or who want to work with what they read.

Ebooks and reading marks stay on the device by default; optional syncing requires an explicit action. Readest says it encrypts sensitive data and follows secure app-code practices, while recognizing that electronic storage and transmission cannot be made completely secure. The software is open source under AGPL-3.0, and screen reader support broadens its usefulness for visually impaired readers.

For more options, browse our Ebook Reader Software guide.

Key features

• Annotations and search: Highlights, bookmarks, notes and library search cover common study and reference needs without requiring a separate notes workflow.
• Parallel reading: Two books remain side by side with synchronized movement, a practical advantage for comparing editions or consulting a second text.
• Lookup and translation: Word lookup in Wiktionary or Wikipedia is useful for reading with quick reference. Passage translation uses Google, Azure or DeepL providers; the daily character allowance varies by plan.
• Text to speech: On-device, browser and cloud options offer flexibility in how books are heard. Unlimited AI read-aloud hours are included with Plus, rather than the free plan.
• Library connections and export: OPDS and calibre connections help readers manage catalogs, while Readwise and Hardcover export gives highlights a route beyond the reader.
• Cloud sync: WebDAV, Google Drive, OneDrive, iCloud Drive and S3-compatible storage are supported, but third-party cloud syncing is a paid-plan feature.

Pricing

Readest uses a freemium model. The Free Plan has 500 MB of cloud storage and 10K AI translation characters per day, a reasonable starting point for a small library or occasional translation. It does not include third-party cloud sync, and uploads above the free 500 MB limit pause after downgrading. Books already in Readest Cloud remain downloadable.

Plus costs $4.99 a month and includes 5 GB cloud sync storage, 100K AI translation characters per day and unlimited AI read-aloud hours. It is the clearest fit for regular listeners who also need more storage or translation capacity. Pro costs $9.99 a month, raises storage to 20 GB and translation to 500K characters per day, making it better suited to larger libraries or frequent translation; the plan's listed benefits do not include unlimited AI read-aloud hours.

The Lifetime Plan is a one-time payment, with storage choices of 1 GB for $9.99, 2 GB for $14.99, 5 GB for $29.99 or 10 GB for $49.99, plus Full Customization for $19.99. These choices suit readers who prefer an upfront payment, but the listed storage tiers are smaller than Pro's 20 GB. Free and paid users can seek support through documentation, community channels, GitHub issues and support email.

Platforms

Readest runs on web, Windows, macOS, Linux, iOS and Android, so it can serve readers moving between desktop and mobile environments. Offline reading is supported, while syncing across third-party cloud services requires a paid plan.

Who it's for

Readest is a strong fit for readers with books in varied formats who want annotation, reference tools and optional listening in one reader. It is especially compelling for people who use OPDS or calibre libraries, compare texts in parallel, or value open-source software. Readers who need extensive cloud storage without paying, or who do not need its broader toolset, may be better served by a simpler or library-focused option.

Pros and cons

• Pros: Broad file support, annotations, lookup, translation and multiple text-to-speech modes bring useful reading and study tools together.
• Pros: Local-by-default storage and AGPL-3.0 licensing suit readers who value control and open-source software.
• Pros: Six platforms, OPDS and calibre connections, and highlight exports accommodate varied reading setups.
• Cons: Free cloud storage is capped at 500 MB, and third-party cloud sync pauses without a paid plan.
• Cons: AI translation has daily character limits on Free and Plus, so heavier use points toward Pro.

Alternatives

eBoox is another freemium reader with a free plan and Android, iOS and web support; consider it if that platform set meets your needs.

Libby is free to install, with digital content free to borrow using a valid library card and no subscription costs or in-app purchases. Choose it when borrowing library titles is the priority.

PocketBook Reader offers a free reader app on Android and iOS, with app stores indicating in-app purchases. It is an option for readers focused on those two platforms.

Thorium Reader is a free option for iOS, Linux, macOS and Windows, developed by EDRLab, a Paris-based non-profit development laboratory. Consider it if those platforms and a free reader are the main requirements.

FBReader has a free plan across Android, iOS, Linux, macOS and Windows. Its current code is closed source, so readers seeking an open-source reader may prefer Readest.

Adobe Digital Editions is free and supports Android, iOS, macOS and Windows; it is a straightforward alternative for readers who want a free option on those platforms.

ReadEra offers free reading without ads or registration, and its $14.99 one-time Premium plan includes Google Drive sync, background text-to-speech, quotes and more. It may suit readers who prefer a one-time paid upgrade over Readest's monthly plans.

Moon+ Reader is an Android-only alternative with a $11.99 one-time Pro plan that includes ad-free use, PDF support and free upgrades for life. Consider it if you read on Android and prefer a one-time purchase.

Verdict

Choose Readest if you want a format-flexible reader with annotation, lookup, listening and library tools across desktop and mobile platforms. Its open-source approach and local-by-default storage strengthen the case, but the 500 MB free cloud cap and paid-only third-party sync make it less suitable for readers who need generous syncing at no cost.