# Sylex: Make sense of the slashes

> A hand-rolled regex lexer powers the explainer; ReDoS detection and native $-expansion replace mode round it out - all client-side, dependency-free.

Sylex is an interactive regex explainer that breaks any pattern down into its parts and tells you what each one does. It runs on a hand-rolled lexer rather than the browser's regex engine, which is what lets it flag ReDoS-prone constructs and power a native $-expansion replace mode in the same pass. It is a from-scratch, dependency-free build that runs entirely in the browser, so you can download it and run it locally.

## About the app

Frontend craft on a tricky domain

## What to take away

- A hand-rolled regex lexer powers the explainer; ReDoS detection and native $-expansion replace mode round it out - all client-side, dependency-free.
- Download: Sylex (ZIP)

## Tags

Free software, Sylex

## Read the full write-up

/downloads/sylex.zip

## We build this for clients

https://dfieldsolutions.com/en/services/full-stack

## More from the lab

- https://dfieldsolutions.com/en/lab/kindra.md — Kindra: Miss a beat, not the rhythm
- https://dfieldsolutions.com/en/lab/voxara.md — Voxara: Argue better. Lose gracefully
- https://dfieldsolutions.com/en/lab/wraithward.md — Wraithward: Spot the bait before you bite
- https://dfieldsolutions.com/en/lab/riventide.md — Riventide: Revenue, divided fairly. Automatically

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Source: https://dfieldsolutions.com/en/lab/sylex
DField Solutions — Torony köz 5-1.a, 2120 Dunakeszi, Hungary — +36 20 722 0002 — dezso@dfieldsolutions.com
Booking: see https://dfieldsolutions.com/en/contact