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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

Format code, edit PDFs and images, debug tokens, and estimate AI costs with 334 free tools that run in your browser. Chain them into recipes and keep a privacy receipt showing the work stayed on your device.

Explore all tools Private invoice editor
334
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.

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Security

Password Generator

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

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Colour Tools

Color Picker

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

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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.

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Security

Hash Generator

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

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AI Toolkit

LLM Cost Estimator

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

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API Toolkit

Webhook HMAC Signer

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

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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

A single tool solves one step. Recipes let you chain several steps, save the sequence for jobs you repeat, and download a privacy receipt that records the processing ran on your device. See how privacy receipts are built.

Document Generator

A private invoice canvas. Edit the layout and line items on your device, then export a PDF or PNG without sending the file to a server.

Recipe Studio

Chain steps such as JSON, minify, then Base64, or PDF compress, then protect. Share a recipe as a link; the steps live in the URL hash, not on a server.

Privacy receipts

Download a JSON record of client-side processing for JWT, PDF, PII, and file jobs, then check it later with the Receipt Verifier.
New · On-device documents

Create professional invoices without leaving your browser

Document Generator is an invoice workspace that runs on your device. Arrange text and shapes, let the line-item totals update as you type, and download a PDF or PNG. It follows the same client-side approach 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

Work out a tip or VAT with the discount and tip calculator, check social post limits, build an email signature, create a memorable passphrase, or pull contacts out of pasted text. Everything stays in your browser.

Gap Tools

Jobs AI chat and upload sites under-serve

View Gap Tools hub

Write an llms.txt policy, plan MCP bake manifests, review cookie jar risks, diff webhook replays, or strip metadata from Office files. These jobs need your real files, so they run on your device instead of on a server.

Just shipped

8 new tools for API, DevOps, and AI work

Browse new tools

Sign webhooks, query JSON with JSONPath, lint a Dockerfile, estimate LLM costs, and more. Each one runs client-side, so nothing is uploaded.

Cloud & data

Cloud, API, and data tooling

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Build Kubernetes manifests and GitHub Actions workflows, explore GraphQL and OpenAPI schemas, read IAM policies and certificates, simulate RAG chunking, mine logs, and sort Tailwind classes, all in your browser. More in the DevOps generators and API toolkit.

More new tools

AI ops, security, and frontend extras

Browse new tools

Draft chat message arrays, score prompts against a rubric, inspect SVG paths, estimate bundle size, annotate accessibility issues, summarize Terraform plans, build MongoDB queries, review JWT risks, and work with CIDR ranges.

Categories

Browse tools by category

Each category groups related tools, so you can tidy code, clean up copy, check SEO tags, or build a color palette without searching the whole list. The code tools and PDF tools are good places to start.

Popular

Popular tools

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Formatters, generators, and converters that handle the small, repetitive parts of coding and content work.

New

Recently added tools

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The latest additions to the toolkit. Bookmark the ones you use, check the changelog for what changed, and tell us which tool to build next.

Image tools

Edit images in bulk, privately in your browser

All image tools

Drop in your images to compress, resize, crop, rotate, convert, or watermark them. Before you share photos, strip EXIF location data. Files never leave your device.

PDF tools

PDF tools that stay on your device

Document Generator

Merge PDFs, split them, compress a PDF for email, add a password, or convert pages to images in your browser. For invoices, Document Generator gives you an editable layout with live totals and on-device PDF export. Files never leave your device.

Why OneDevToolkit

Built for speed and privacy

The tools are small, load quickly, and keep your work on your machine, so you can get the task done and move on.

Fast results

Tools run in your browser, so there is no upload step and no wait for a server to send results back.

Private by design

The text and files you open in a tool are processed on your device. We do not upload or store them. See the privacy policy for what the site itself collects.

Free to use

Every tool is free, with no sign-up required and no ads. Very large files are limited only by your device's memory.

Desktop and mobile

Responsive layouts that work in current desktop and mobile browsers.

Keyboard friendly

Press Ctrl+K (or Cmd+K) to search every tool, and use the keyboard to move through forms and results.

Light & dark mode

Switch themes from the header. Your choice is remembered on this device.

Save favorites

Bookmark the tools you use most. Favorites are stored locally in your browser.

Lightweight pages

Built with plain JavaScript and a few small libraries instead of a heavy framework, so pages stay quick to load.

334
Tools available
19
Tool categories
20+
Starter recipes
100%
Client-side
AI Toolkit

Plan prompts and AI costs before you call an API

Write and refine prompts, count tokens, reuse templates, and compare model pricing without pasting your prompt into a third-party service. For a worked example, read the GPT, Claude, and Gemini cost guide.

Explore AI Tools
Code Tools

Format, validate and transform

Paste messy HTML, CSS, JavaScript, or JSON and get readable output in one click. The JSON formatter also flags syntax errors, which helps when you are debugging an API response, reviewing a pull request, or preparing snippets for docs.

Compare

OneDevToolkit vs the rest

Many tool sites now process some files locally. OneDevToolkit pairs local processing with verifiable privacy receipts and Recipe Studio for chaining tools. The comparison hub covers IT Tools, DevToys, CyberChef, and others in more detail.

FeatureOneDevToolkitTinyWowSmallSEOToolsCodeBeautify
Multi-category tool library (334 tools here)YesYesYesNo
100% private (local processing)YesNoNoNo
No adsYesNoNoNo
Dark modeYesNoNoYes
AI Prompt ToolkitYesNoNoNo
Command palette (Ctrl+K)YesNoNoNo
CSS GeneratorsYesNoNoYes

Full comparison hub · Other services change their features often, so check their sites for current details. Competitor names are trademarks of their owners. See Attributions.

Why OneDevToolkit

Built for privacy-conscious developers

Local processing you can check, workflows you can chain, and 334 tools in one place.

Privacy Receipts

Download a JSON record showing the processing stayed in your browser, useful when a client asks how their files were handled. How receipts work

Recipe Studio

Chain JSON, minify, and Base64 steps (and many others) without server round-trips, then share the workflow as a link. Open Recipe Studio

334 local tools

Formatters, a JWT decoder, PDF and image studios built on WebAssembly, and AI cost estimators, all running client-side. Browse all tools

Technical Guides

Featured Developer Guides & Workflows

All 12 guides

Practical, step-by-step engineering walkthroughs for local token debugging, client-side document processing, and verifiable API security.

Private PDF Workflows

Merge, redact, stamp, and compress documents on your device without transmitting page contents to cloud servers.

Local JWT Debugging

Inspect claims, verify HMAC signatures, and check token expiry without exposing auth credentials to third-party endpoints.

Verify Webhook Signatures

Compute and test HMAC SHA-256 signatures for Stripe, GitHub, and Shopify webhooks using the Web Crypto API.

Compress PDFs Locally

Reduce document file sizes to meet email limits while keeping confidential contracts and statements on your computer.

LLM Token Cost Comparison

Calculate and compare prompt, completion, and batch pricing across OpenAI, Anthropic, and Google Gemini models.

Redact Sensitive PII

Mask emails, phone numbers, credit cards, and API secrets in raw logs before pasting into public AI chats or issue trackers.
From the blog

Guides worth reading

All posts

Practical AI, SEO, and privacy-first workflow articles - written for people who ship software.

Document with sensitive lines covered before sharing, next to a laptop
PDF Privacy · 8 min read · September 30, 2026

How to Black Out Text in a PDF for Free (and Check It Is Really Gone)

Drawing a black box over text in a PDF often leaves the words underneath, still copyable. Here is how to black out information properly for free, and a two-minute test to prove it worked.
Printed PDF documents and a laptop on a desk while preparing files for private compression
PDF Privacy · 7 min read · September 27, 2026

How to Compress a PDF Privately in Your Browser

A practical way to get a PDF under an email or upload limit without sending it to a stranger’s server, plus what each compression level actually does to your file.
Laptop and hardware security key on a desk used while inspecting authentication tokens locally
API Security · 6 min read · September 27, 2026

Decode JWTs Safely Without Cloud Debuggers

A JWT in your clipboard is a live credential. Here is how we read claims, check expiry, and verify signatures without handing the token to a stranger’s server.
FAQ

Frequently asked questions

See all FAQs

Yes. All 334 tools are free to use, with no sign-up and no credit card required.

Yes. The tools process your text and files locally in your browser. We do not upload, store, or track the content you work with. Site analytics are covered in our privacy policy.

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. The layout adapts to phone and tablet screens. Heavy jobs such as large video or PDF files run faster on a desktop, because all processing uses your own device.

View more FAQs

Pick a tool and start now

Free to use, no sign-up required. Every tool runs locally in your browser.

Get started free
334 tools, no upload waitResults appear in your browser
Private by designYour files and text stay on your device
Free to useNo credit card, no ads, no account needed
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