We built the test
for getting stuck.
Litmusly is a GitHub App. On every pull request it dips a grounded persona into your preview deploy, walks it the way a real visitor would, and reads the reaction back as one comment. This page is what it is, and why it exists.
Software you can compile, but nobody can use.
Most UX bugs are not caught by tests. They are caught by users, after launch. Pixel diffs catch what you can see. Unit tests catch what you can compile. The moment someone opens your preview and gets stuck lives in nobody’s CI.
So it ships. You find out on Tuesday, from a Slack thread. Litmusly moves that moment earlier, onto the pull request, while the change is still cheap to fix.
It is one focused tool doing one thing well: a grounded persona, a real preview, one honest comment. Not a research platform, not a replacement for talking to your users. A litmus test.
Four things we refuse to compromise.
Honest over flattering.
A reagent reports what it hit, not what you hoped. Candid, not complimentary. Many PRs earn zero findings, and get zero.
Grounded, not generic.
Every reaction comes from a walk of your real rendered preview. Not your code, not a mock. If it didn't happen in the browser, it isn't in the comment.
Quiet by design.
One comment, edited in place on every push. No dashboard to check, no thread to mute. Zero noise is the point, not a setting.
A third lane.
Not a replacement for unit tests or visual diff. The lane that catches dead-ends, confusing copy, and “where do I click”, after everything compiles.
Small, independent, and founder-led.
Litmusly is built by a small team that ships product for a living. There is no research department here and no growth org. The people who write the reagents are the people who answer your email. If something feels off, tell us, and you will hear back from someone who can change it.
See what your
PR reacts to.
Install the GitHub App, open a pull request, and read your first reaction in under five minutes.