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const format = (json) => {
  return JSON.stringify(json, null, 2);
}
JSON Formatter
? Valid JSON detected
SHA-256:
a4fg9b2d1e7c...
Regex /^[\w-.]+@[\w-]+\.[a-z]+$/i
? 3 matches found
Privacy-verified workflows · nothing uploaded

The privacy-verified
workflow toolkit for developers

Chain local tools into recipes, keep secrets on your device, and prove it with privacy receipts. 321 client-side utilities — not another upload farm.

Explore all tools Private invoice editor
321
Local tools
20+
Starter recipes
100%
On-device
0
Uploads
PDF & Documents

Document Generator

Build invoices on a private visual canvas — edit text and shapes, recalculate totals live, then download PDF or PNG. Nothing is uploaded.

Open editor
Code Tools

JSON Formatter

Beautify, validate and explore JSON data instantly with real-time syntax checking.

Open tool
Security

Password Generator

Create strong, cryptographically secure passwords with customisable length and character sets.

Open tool
Colour Tools

Color Picker

Pick, convert and copy colors across HEX, RGB, HSL and CSS variable formats.

Open tool
Web Tools

URL Parser

Break down any URL into its protocol, host, path, query parameters and hash fragment.

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Developer

Regex Tester

Test and debug regular expressions against any text with live match highlighting.

Open tool
Security

Hash Generator

Compute SHA-1, SHA-256 and SHA-512 hashes instantly using the Web Crypto API.

Open tool
AI Toolkit

LLM Cost Estimator

Compare GPT, Claude, and Gemini pricing from prompts or token counts — privately in your browser.

Open tool
API Toolkit

Webhook HMAC Signer

Sign and verify GitHub, Stripe, and Slack webhook signatures with Web Crypto — no upload.

Open tool
DEVELOPERS*DESIGNERS*MARKETERS*SEO PROS*FULL-STACK*DEVOPS*DATA ENGINEERS*CONTENT CREATORS*PRODUCT TEAMS*STARTUPS*FREELANCERS* DEVELOPERS*DESIGNERS*MARKETERS*SEO PROS*FULL-STACK*DEVOPS*DATA ENGINEERS*CONTENT CREATORS*PRODUCT TEAMS*STARTUPS*FREELANCERS*
Beyond a tool directory

Recipes, receipts, and workflows

Open Recipe Studio

Competitors list isolated tools. OneDevToolkit lets you chain them, re-run weekly jobs, and download a privacy receipt that proves processing stayed on your device.

Document Generator

Private invoice canvas — edit layout and line items on-device, then export PDF or PNG with no upload farm in the middle.

Recipe Studio

Chain JSON → minify → Base64, JWT debug packs, PDF compress → protect, and more. Share via URL hash — no server.

Privacy receipts

Download JSON proof of client-side processing for JWT, PDF, PII, and file jobs. Verify anytime.
New · On-device documents

Create professional invoices without leaving your browser

Document Generator is a privacy-first invoice workspace on OneDevToolkit: arrange text and shapes, keep line-item maths in sync, and download a PDF or PNG — the same client-side promise as our PDF and recipe tools.

  • Starter invoice layout you can recolour and rearrange
  • Text, shapes, brand colours, lock, duplicate, undo/redo
  • Live subtotal, tax, and total as you add or remove rows
  • Local autosave · PDF/PNG export · zero uploads
Open Document Generator Browse PDF tools

Modern Business Swipe or click a page · full invoice from header to footer

Everyday Tools

Useful for everyone — not just developers

View Everyday hub

Tip & VAT maths, social post limits, email signatures, memorable passphrases, and contact list extraction — private in your browser.

Gap Tools

Jobs AI chat and upload sites under-serve

View Gap Tools hub

llms.txt policy, MCP bake manifests, cookie jar risks, webhook replay diffs, and Office ZIP metadata scrubbing — on-device, not uploaded.

Just shipped

8 new tools for modern builders

Browse new tools

Webhook signing, JSONPath queries, Dockerfile linting, LLM cost estimates, and more — all client-side, nothing uploaded.

Phase 2 & 3

Cloud, API, and data tooling

View all new

Kubernetes manifests, GitHub Actions, GraphQL, OpenAPI, IAM, TOTP, certificates, RAG chunking, log mining, SQL builder, and Tailwind sorting — private in your browser.

More new tools

AI ops, security, and frontend extras

Browse new tools

Chat message studios, prompt rubrics, SVG paths, bundle estimates, a11y audits, Terraform plans, Mongo pipelines, JWT threat notes, and CIDR toolbelts.

Categories

Every tool, perfectly organised

Pick a category and jump straight in ? whether you need to tidy code, clean up copy, check SEO tags or generate a colour palette. Each group gathers related tools so you spend less time hunting and more time shipping.

Popular

Most-used tools this week

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These are the utilities people open again and again ? formatters, generators and converters that remove the busywork from everyday coding and content tasks.

New

Recently added tools

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Fresh additions to the toolkit. Try them early, bookmark the ones that fit your workflow, and tell us what you want next.

Image tools

Edit images in bulk ? privately in your browser

All image tools

Compress, resize, crop, rotate, convert and watermark with a premium drag-and-drop studio. Files never leave your device.

PDF tools

PDF tools that stay on your device

Document Generator

Merge, split, compress, protect, and convert PDFs in your browser — plus Document Generator for private invoice layouts with live totals and on-device PDF export. Files never leave your device.

Why OneDevToolkit

Built for speed, privacy and delight

We obsess over every pixel, every millisecond and every byte ? so you can focus on building.

Blazing fast

Every tool runs instantly in your browser. No uploads, no server round-trips, no waiting.

100% private

Your data never leaves your device. Nothing is stored, tracked or analysed.

Free forever

Every tool is free with no limits, no sign-up required and absolutely no ads.

Works everywhere

Responsive, accessible and tested across all modern browsers and devices.

Keyboard first

Full keyboard navigation, Ctrl+K search, and shortcuts for every action.

Light & dark mode

Gorgeous in both themes. Your preference is remembered across sessions.

Save favourites

Bookmark your most-used tools for instant access, stored locally in your browser.

Open ecosystem

Built with vanilla JS ? no heavy frameworks, no tracking scripts, just fast code.

321
Tools available
19
Tool categories
20+
Starter recipes
100%
Client-side
AI Toolkit

Supercharge your AI workflow

Craft better prompts, count tokens, manage templates and compare AI models ? all in one place.

  • Prompt Generator & Optimizer
  • LLM Cost Estimator across GPT, Claude & Gemini
  • Token Counter for GPT-4, Claude, Gemini
  • Prompt Library with 100+ templates
Explore AI Tools
Code Tools

Format, validate and transform

Paste messy HTML, CSS, JavaScript or JSON and get readable output in a click. Handy when you are debugging, reviewing a PR or preparing snippets for docs.

Compare

OneDevToolkit vs the rest

Client-side processing is table stakes in 2026. OneDevToolkit adds verifiable privacy receipts and Recipe Studio — features competitors like IT Tools, DevToys, and TinyWow do not ship. Read the full comparison.

FeatureOneDevToolkitTinyWowSmallSEOToolsCodeBeautify
321 toolsYesYesYesNo
100% private (local processing)YesNoNoNo
No adsYesNoNoNo
Dark modeYesNoNoYes
AI Prompt ToolkitYesNoNoNo
Command palette (?K)YesNoNoNo
CSS GeneratorsYesNoNoYes

Full comparison hub · Competitor names are trademarks of their owners. See Attributions.

Why OneDevToolkit

Built for privacy-conscious developers

Not another upload farm — verifiable local processing, chainable workflows, and 321 tools in one suite.

Privacy Receipts

Download JSON proof that processing stayed in your browser — auditable for client contracts. How it works

Recipe Studio

Chain JSON → minify → Base64 (and more) without server round-trips. Share workflows via URL. Open recipes

321 local tools

Formatters, JWT debuggers, PDF/image WASM studios, AI cost estimators — all client-side. Browse tools

FAQ

Frequently asked questions

See all FAQs

Yes. Every one of our 321 tools is completely free with no limits, no sign-up and no credit card required.

Absolutely. All processing happens locally in your browser using JavaScript. We never upload, store or track the content you work with.

No. Every tool works without an account. Creating a free account lets you save favourites and sync history across devices.

Once a page is loaded, most tools work without an internet connection since all processing runs locally.

Yes. OneDevToolkit is fully responsive and tested on iOS and Android. The layout adapts beautifully to any screen size.

View more FAQs

Ready to supercharge your workflow?

Free forever — no sign-up required. Every tool runs locally in your browser.

Get started free
321 tools, zero waitingEverything runs instantly in your browser
100% private by designYour data never leaves your device
Free forever, no catchNo credit card, no ads, no limits
ESC