Tool index
Free Developer Tools for JSON, API Testing, Regex & More
Explore fast, browser-based developer tools for JSON tools, API testing, regex generation, design tokens, image optimization, and more — all running locally in your browser.
Free • No signup • Fast browser-based workflows
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Signal Playground
Run JavaScript and preview HTML/CSS instantly in your browser.
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Image Truth
Reduce image size without losing quality. Runs locally — no uploads.
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Image Placeholder
Generate placeholder images with simple URLs.
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Flowchart Studio
Turn code, JSON, and plain steps into clean flowcharts instantly.
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Smart Regex Builder
Generate and test regex patterns instantly — no setup required.
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JSON to Form
Turn JSON into editable form UI — no backend required.
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JSON Visualizer
Format, clean, and explore large JSON payloads locally.
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API Mock Generator
Generate realistic API mock data for frontend tests and demos.
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Color System Generator
Generate semantic light/dark design tokens from one color.
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API Request Playground
Test API endpoints fast with local request history.
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Deep Work
Pomodoro timer with focus insights and local session tracking.
Module
Reset
Quick stress relief tools for browser-based mental resets.
Workspace Hub
Pick up where you left off
Reopen saved workspaces across Signal Playground, API tools, JSON tools, regex, and design systems from one place.