I bought this tiny $40 ereader… Then rewrote it
Meet the Xteink X4, a tiny 4.3" E-ink eReader that can cost around $40 and is small enough to slip in a pocket. If you’re a security professional (or just someone who lives in technical docs) and you want a way to read without getting pulled into notifications and doomscrolling, this minimalist ereader is a surprisingly good alternative to reading on your phone.
What makes the Xteink X4 interesting isn’t just the price it’s how much you can do with it. It’s ESP32-based, which makes it a genuinely approachable device for anyone learning firmware development and embedded C++. I walk through the usability, why I recommend the community firmware for a cleaner UI, and how I use it with Calibre and Calibre-Web for a more self-hosted, library-style workflow instead of being locked into a vendor ecosystem.
This isn’t a polished Kindle replacement. It’s a small, cheap, readable E-ink screen you can actually experiment with. But it's perfect if you want a low-risk platform to practice building features, flashing builds via PlatformIO in VS Code, and getting hands-on with the constraints that come with embedded hardware.
If you’re curious about a pocket-sized ereader that doubles as a firmware playground, this one’s worth a look.
Buy the Xteink X4 on their website here: http://xteink.com/products/xteink-x4
Or search for it on Ali Express!