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Regexper – Regular expressions visualizer

Screenshot of regexper.com captured 2026-07-20
Page preview · captured 2026-07-20

Resurfaced independently across 5 calendar years, with breakout response in 2 of them.

submissions
7
submitters
7
observed span
2013–2024
peak thread · 127 comments
510 pts
latest 20+ return · 2018-01-30
510 pts

Submission timeline

2007–2026

One slot for every year since HN launched. Height is that year's peak points; orange marks a 100+ point or 50+ comment breakout. Select a bar to open its strongest thread.

First comments on top threads

HN comment order

It's always neat to see where one's ideas go! AFAIK, I was the first person to create dynamic railroad diagrams for regular expressions (maybe 12 or 13 years ago). I got the idea from json.org, which I think was Douglas Crockford's brainchild. My initial implementation was strfriend.com (in Lisp: well under 1,000 lines, including views), and I think its main claim to fame was that Jeff Atwood made fun of it on Twitter. (I was truly clueless at promoting myself…

ken·510-point thread·

Hello, I'm the creator of this (trevmex is one of my co-workers). I just want to thank everyone for the feedback so far, I am looking into the issues that have been brought up (they'll have to wait until this evening to be fixed though...I have a day job).

Related, "regexr" is my favorite tool for building regexes. Is your project's name inspired from it ?

screye·8-point thread·

I'm using it for quite a while already, there was a link to them here, like several months ago.

vittore·2-point thread·

The first top-level comment from each of the four biggest threads, in HN’s own order. Excerpts are shortened; open a comment for full context.

Breakout years
2

100+ points or 50+ comments

Total points
1006

reference only — not used in Hall rules or ranking

Total comments
231

reference only — not used in Hall rules or ranking

Every submission

DateTitle as submittedByPointsComments
2013-01-02Regexper: Beautiful regexp visualizationsFirst breakouttrevmex466127
2013-04-04Regexper: JavaScript Regular expression visualizer using railroad diagramstilt21
2013-11-28Regexper, awesome tool by Jeff Avallone for graphing Regexiamtechaddict10
2014-08-07Regular Expression Syntax Diagramscrawshaw180
2018-01-30Regexper – Regular expressions visualizerHall induction · Best thread · Latest 20+ point returnxchip510102
2020-11-30Regexpersiliconmountain10
2024-05-29Visualize Regex Beautifully – Regexperericciarla81