Edsger

What it does

Edsger is a Clojure REPL (Read-Eval-Print Loop) designed for the reMarkable 2 tablet that accepts handwritten input. It lets developers write Clojure code by hand on the tablet's screen and execute it directly, with results displayed on the same device.

Who it is for

This targets Clojure developers who own a reMarkable 2 tablet and want a mobile, low-distraction environment for experimenting with code. The handwriting-based interface appeals to users who prefer pen input over keyboards or who want to work away from traditional computers.

Pricing

The site does not show prices.

How it stands out

Edsger combines two relatively niche elements: Clojure programming and handwritten input on e-ink tablets. Most REPLs are keyboard-first tools; this one inverts that by making the stylus the primary input method. The reMarkable 2's e-ink display and low-latency pen support make it a reasonable fit for this use case, though it remains a specialized tool for a small audience. The project appears to be a personal technical experiment rather than a commercial product seeking broad adoption.

What a founder should check

First, verify the actual size of the reMarkable 2 user base interested in Clojure. Clojure has a modest developer population already, and the overlap with reMarkable owners—who typically use the tablet for note-taking and reading—is likely very small. Check whether demand exists beyond novelty appeal.

Second, examine switching costs and lock-in for users of existing Clojure development environments (VS Code, Emacs, Vim, web-based REPLs). Developers have invested time in editor configurations, plugins, and workflows. A handwritten REPL would need to offer compelling advantages in speed, cognitive flow, or portability to justify switching.

Third, assess whether the reMarkable 2 hardware constraints—screen size, refresh rate, lack of persistent background processes—create fundamental limits on what a productive Clojure workflow could look like. Handwriting recognition accuracy, latency between writing and execution, and the ability to view complex output on a small e-ink screen are practical questions that would determine whether this remains a curiosity or becomes genuinely useful.