Responsive Tool vs CurlyJSON

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

Responsive Tool compared with CurlyJSON
Detail	Responsive Tool	CurlyJSON
What it does	Free responsive website checker for mobile, tablet and desktop	JSON Formatter & Validator — Free, Private & Offline
Stage	Not given	Not given
Founded	Not given	Not given
Based in	Not given	Not given
Pricing model	Free	Freemium
Pricing	Not given	Free for all tools. Pro: $29.99 per year or $4 per month, plus tax.
Key features	Test multiple device viewports simultaneously Real CSS viewport rendering Share setup links Custom pixel width testing No installation required Sync scroll across panes Browser-based with no account needed	Validate JSON with precise line and column errors Repair invalid JSON fixing trailing commas, quotes, and comments Preserve large integers without rounding Detect and mask API keys, tokens and passwords
What makes it different	Compare multiple real device widths side by side instead of switching one at a time Faster than DevTools for checking several device sizes at once Entirely browser-based with no setup, signup or download Built and maintained by one developer in the open	Keeps large numbers exactly as written instead of silently rounding them like most online formatters All free tools run entirely in your browser, working offline without uploading data Automatically detects and warns about secrets like API keys and passwords
Free plan	Not given	Not given
Open source	Not given	Not given
Platforms	Not given	Not given
Public API	Not given	Not given
Community votes	0	0
DR (Domain Rating by Ahrefs)	Not checked yet no change since last check	Not checked yet no change since last check
Trust Flow (Majestic)	1	7
Citation Flow (Majestic)	25	13
Referring domains (Majestic)	14	2

4 details filled in for both companies.

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