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70 browser-local tools · 2 guides

Developer tools. Open one and work.

Format JSON, inspect JWTs, test regex, clean images and diagnose browser storage. Open a tool and work. Your input is not uploaded.

All 70 toolsPrivacy model
No accountNo input uploadRuns in this tab

Open a direct tool

No setup. Start with the result.

Format JSONConvert a timestampTest a regexEncode or decode Base64Inspect a JWTConvert cURLCompress an imageGenerate a QR codeDiagnose cookiesRemove photo metadata
01Deeper diagnostics

Useful when the obvious tool is not enough.

These tools go beyond basic conversion: they expose policy conflicts, browser limits, unsafe content and hard-to-see differences.

Browse all 70
Browser Storage Capability ProbeTest browser storage with write, read, and delete evidence.Cookie Header InspectorParse Cookie and Set-Cookie headers, then validate policy.Secret ScannerFind and redact secrets before sharing text.JSON RepairFix JSON-like output from AI, logs and configs.Stack Trace AnalyzerFind actionable frames in JavaScript and Python stacks.Image DiffCompare images by RGBA or perceptual Delta E regions.
02Color engineering bench

Four precise jobs, not one generic picker.

Convert, verify, sample and compose color without uploading screenshots or flattening every task into the same shallow interface.

Open color shelf
01

Convert & tune

HEX, RGB, HSL and OKLCH with perceptual scales.

02

Audit contrast

WCAG pairs, repair suggestions and palette matrices.

03

Sample an image

Extract local pixels into practical design tokens.

04

Build gradients

Compose CSS and sample text contrast across the ramp.

03Advanced entry points

Use these when a direct tool is not enough.

They are optional shortcuts for ambiguous input and repeated multi-step work, not prerequisites for using MonoTools.

When the format is unclearPaste first, choose second.Use Magic Paste when you are not sure whether the text is JSON, a JWT, headers, CSV, SQL or a log.Route a pasted payloadWhen the same steps repeatChain cleanup into a reusable recipe.Use Workflow Builder when you repeatedly decode, redact and format the same kind of payload.Build a local workflow
04A visible privacy boundary

Private by architecture, not by promise.

The useful work happens inside the browser tab. Network boundaries stay legible, and export is always an explicit action.

Tool input is handled by browser APIs and local JavaScript.

Tool-to-tool handoffs use short-lived session storage, not URLs.

Favorites, history and themes remain on the device you chose.

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Runtime receiptVERIFIED LOCALLY
Input uploads
0
Account required
No
Tool handoff in URL
Never
Local favorites
On device
Browser
boundaryinput stays here
The full shelf

Keep the useful tools close.

Browse by task, pin what you use, and build a private workbench that feels familiar the next time something breaks.

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