Cool Reader is an old-school Android e-book reader built for people who already have folders full of EPUB, FB2, TXT, and MOBI files. It’s not a glossy storefront, a social reading platform, or an AI-powered study assistant, but a simple app that gives you full control over how all your books look and feel on a screen.
Its Android history goes unusually far back: F-Droid’s older builds list Android 1.5+ support, while current third-party APK listings for later Android builds commonly show Android 1.6+. The app is free, open-source, and donation-supported rather than subscription-driven, which in 2026 already puts it in a fairly rare category.
The maintenance story is where honesty is required. SourceForge still shows a 2018 project update date, F-Droid's package is older, the latest tagged GitHub release is cr3.2.58, and the current Android build file still shows version 3.2.57-1. That fragmented release trail does not make the app useless, but it does make it feel like a beloved project that has aged unevenly rather than a neatly maintained modern Android product.
The shortest honest description is this: Cool Reader is a tinkerer's e-reader. It is designed less like Kindle or Google Play Books and more like a flexible reading engine for people who already know what they want from a book app. It includes a built-in file browser, quick access to recent books, support for online OPDS catalogs, zip-archive reading, a table of contents, bookmarks, text search, and text-to-speech — all without requiring a mandatory cloud account.
Its annotation tools are not fancy in the modern study-app sense, but they are genuinely useful. Cool Reader supports bookmarks on text fragments with comments or corrections, and it can export those bookmarks to a text file. That makes it pretty handy for proofreading, language study, or simply marking favorite passages without turning reading into homework.
The format list of Cool Reader covers EPUB, FB2, DOC, TXT, RTF, HTML, CHM, TCR, PDB, PRC, MOBI, and PML — a range that reflects a developer who truly expected readers to bring their own messy, mixed-format libraries.
Customization is really the headline feature. Cool Reader supports additional TTF fonts loaded from storage, extra textures and backgrounds through its .cr3 folders, brightness control by sliding along the left edge, custom tap-zone and key actions, external CSS styling, and text selection by double tap. It also supports Chinese, Japanese, and Korean text, plus TXT encoding autodetection — the kind of practical, nerdy feature set that only makes sense when a developer genuinely cares about real-world reading habits.
For FB2 readers in particular, Cool Reader still feels oddly special. The app specifically highlights strong FB2 support for styles, tables, and footnotes, and that niche matters more than it may seem. Many modern readers are better at looking sleek than at handling older Eastern European ebook formats gracefully. Cool Reader still seems to remember where it came from.
In day-to-day use, Cool Reader behaves like a light, older desktop utility that happened to move onto a phone. The project has long described its engine as "fast and small," and that description still fits the app's general personality: it opens text-based books without drama, wastes very little screen space, and stays focused on reading rather than storefront clutter. It is not flashy, but it is efficient.
There are many settings, many menus, and not much hand-holding. Readers who enjoy tweaking margins, tap zones, fonts, and background textures may find the app almost irresistible. Readers who want instant elegance may bounce off it hard.
Design-wise, Cool Reader is functional rather than modern. It does not feel ugly in a careless way — it feels old in a purposeful way, like software built by someone who cared more about text rendering than branding. That can be comforting after a while, but the first impression is unlikely to win any beauty contests. The app has genuine heart, but its face is definitely from another Android era.
Against current Android rivals, Cool Reader sits in a very specific niche. Moon+ Reader is the more polished power-user option, with broader official format support including PDF, DJVU, comics, and Markdown, plus cloud backup, sync, and richer bookshelf tools.
FBReader is the tidier mainstream choice with OPDS support, sync, dictionary hooks, and support for both DRM-free books and Readium LCP-protected titles.
Cool Reader feels more old-school than both, but also more intimate and file-centric. In plain terms, it beats both rivals on one thing: it gives a lot away for free. Moon+ Reader is stronger for PDF-heavy or comic-heavy readers and feels far more actively maintained. FBReader feels cleaner and more conventional, and its current update pace is easier to trust — though its Play listing shows broader data collection and a premium split for some advanced features including read-aloud. Cool Reader remains the best pick for readers who value openness, built-in TTS, old-format friendliness, and maximum page control over modern polish.
For anyone giving Cool Reader a serious try, a few steps make a real difference. Enabling day and night profiles first, then using the left-edge brightness gesture, instantly makes the app feel more comfortable. Adding custom TTF fonts to /sdcard/fonts/ and optional textures or backgrounds to the .cr3 folders is one of the easiest ways to make it feel personal rather than outdated. And if the app starts behaving strangely after an update, the project notes specifically suggest clearing the SD/.cr3/cache folder and the .sqlite database files as a first troubleshooting step.
Cool Reader is not the prettiest Android e-reader in 2026, but it is still one of the most human. It feels like software made for people who actually keep libraries of files and genuinely care about how text sits on a page. Readers who want a cleaner, more actively maintained mainstream choice should look first at Moon+ Reader or FBReader. Readers who want a free, flexible, slightly eccentric reader with real heart will still find something special here.
You may want to check out more software, such as Restaurant Guru or Pleco Chinese Dictionary, which might be similar to Cool Reader.