If you love the idea of an e-reader but don’t want to carry another full-size device, the Xteink X4 takes a different approach: it’s a compact e-ink reader designed to tag along with your smartphone. Thanks to magnetic attachment support on compatible phones, it can sit right on the back of your device, giving you a more eye-friendly screen for reading e-books, articles, and more—without adding much bulk.
Priced at $69, the Xteink X4 can be used on its own, but its standout feature is how portable and phone-friendly it is. The body measures 114 x 69 x 5.9 mm and weighs just 74 grams, making it slim enough to feel more like an accessory than a separate gadget. It’s the kind of setup that could appeal to commuters, travelers, or anyone who wants quick access to reading material on a screen that’s easier on the eyes than a typical smartphone display.
The X4 runs on an ESP32 rather than a traditional mobile-style processor, a choice commonly seen in maker-friendly devices. Storage comes via a 32GB microSD card, and built-in WiFi and Bluetooth make it simple to transfer supported content without fuss.
Battery size is modest at 650 mAh, but the power-sipping nature of e-ink helps it stretch further than you might expect. The quoted battery life is up to 14 days when used for one to three hours per day, which makes it practical for everyday reading, quick reference, and travel situations where charging opportunities may be limited.
The 4.3-inch e-ink display delivers 220 PPI. That’s plenty sharp for text, but the smaller screen also means you’ll see fewer words per page compared with larger e-readers, so page turns and line changes will happen more often. Still, the Xteink X4 isn’t only positioned as a mini book reader. It’s also marketed as a handy secondary display for useful, glanceable items such as boarding passes, calendars, membership cards, and QR codes—exactly the kind of information you might want ready to show without digging through apps or dealing with glare.
File support includes ePUB, text files, BMP, and JPG. One thing to keep in mind: there’s no touchscreen. Navigation and page turns are handled through physical buttons on the side, so the controls are simple and tactile rather than swipe-based.
For readers who want a lightweight, pocketable e-ink companion—especially one that can ride on the back of a phone—the Xteink X4 positions itself as a practical alternative to both traditional e-readers and constant on-phone reading.
