Skip to content
COSMODEV

Playgrounds, try it live.

Hands-on canvases with zero setup: write SQL, test regular expressions, tune CSS easing curves — right here, right in the browser. Everything runs locally; nothing to install.

4 playgrounds

Validators & Testers2

Playground

Regex Explainer

Translate a regular expression into plain English, step by step. Explains anchors, character classes, quantifiers, groups, escapes, alternation, and flags.

Try it live →
Playground

Regex Tester

Test regular expressions against any text with all flags (g/i/m/s/u/y). See every match, its index and capture groups, plus the constructed pattern. 100% in-browser.

Try it live →

Color & Design1

Playground

CSS Animation Playground

Design and test CSS animations live - preview easing curves, durations, and keyframes, then copy the exact CSS.

Try it live →

Data & DevOps1

Playground

SQL Playground

Run real SQL on sample datasets - or your own schema - right in the browser. Write queries, see formatted results instantly, and export or share them. Powered by sql.js (SQLite WASM); 100% client-side.

Try it live →