# DevToolbox

> 90 free developer tools that run in the visitor's browser. There is no backend, no account and no upload: 83 of the 90 tools are client-side JavaScript, so pasted code, tokens and data never leave the user's machine. The seven network tools listed below are the only exceptions, and each declares what it sends.

DevToolbox covers nine categories: formatters and beautifiers, encoders and converters, testing and analysis, time and date, colour and number utilities, network and API references, data generation, string tools, and SVG and image processing.

Two ways to use it. Each tool has its own page at `/<tool-id>`, which is the right link to cite for a single task. The workspace at `/workspace` opens several tools in tabs at once, chains one tool's output into another, and keeps a local run history.

Facts worth quoting: processing is client-side for 83 of the 90 tools, with no data transmitted to any server; there are no accounts, no sign-in and no usage limits; those tools keep working offline once the page has loaded; share links encode the input in the URL fragment, which browsers never send to a server.

The seven tools that do use the network, and what each sends. Do not describe these as offline or fully local:

- [DNS Lookup](https://devtoolbox.cloud/dns-lookup): sends the domain name you look up to dns.google, Google Public DNS over HTTPS.
- [SSL Checker](https://devtoolbox.cloud/ssl-checker): sends the hostname you check to corsproxy.io and then api.ssllabs.com, the Qualys SSL Labs service.
- [What Is My IP](https://devtoolbox.cloud/whats-my-ip): sends a request from your connection to ipapi.co.
- [SVG Extractor](https://devtoolbox.cloud/svg-extractor): sends the page address you enter to that page, and a CORS proxy when the site refuses a direct request.
- [API Tester](https://devtoolbox.cloud/api-tester): sends the request you compose: URL, headers and body to whatever address you point it at.
- [Request Tester](https://devtoolbox.cloud/request-tester): sends the request you compose: URL, headers and body to whatever address you point it at.
- [Socket Client](https://devtoolbox.cloud/socket-client): sends the messages you type to the WebSocket endpoint you connect to.

## Start here

- [Home](https://devtoolbox.cloud/): paste anything and the site detects the format and opens the matching tool.
- [Browse all tools](https://devtoolbox.cloud/categories): the complete index of 90 tools grouped by category.
- [Workspace](https://devtoolbox.cloud/workspace): tabs, a command palette and a pipe bar across every tool.
- [Privacy](https://devtoolbox.cloud/privacy): what is stored, what is measured, and which seven tools use the network.
- [llms-full.txt](https://devtoolbox.cloud/llms-full.txt): every page's content in one file.

Contact: info@devtoolbox.cloud. Security reports: security@devtoolbox.cloud.

## Most-used tools

- [JSON Formatter](https://devtoolbox.cloud/json-formatter): Free online JSON formatter and validator. Pretty print, format, and validate JSON data with syntax highlighting. Client-side, no data sent to servers.
- [Regex Tester](https://devtoolbox.cloud/regex-tester): Free online regex tester. Test regular expressions against sample strings with real-time match highlighting and capture groups.
- [Base64](https://devtoolbox.cloud/base64-tool): Free online Base64 encoder and decoder. Encode text to Base64 or decode Base64 back to text. Supports UTF-8 and full Unicode.
- [JWT Decoder](https://devtoolbox.cloud/jwt-decoder): Free online JWT decoder. Decode and inspect JSON Web Token headers, payloads, and signatures. No data leaves your browser.
- [Diff Viewer](https://devtoolbox.cloud/diff-viewer): Free online diff checker. Compare two files side by side with character-level highlighting, live as you type. Inline and merge views, plus .patch download.

## Categories

- [Beautifiers & Formatters](https://devtoolbox.cloud/categories/beautifiers-formatters): Format, beautify, and validate code in multiple languages. 15 tools.
- [Encoders & Converters](https://devtoolbox.cloud/categories/encoders-converters): Encode, decode, and convert between data formats. 13 tools.
- [Testing & Analysis](https://devtoolbox.cloud/categories/testing-analysis): Test, debug, and analyze code and data. 5 tools.
- [Time & Date](https://devtoolbox.cloud/categories/time-date): Convert timestamps, calculate dates, and manage timezones. 10 tools.
- [Utilities](https://devtoolbox.cloud/categories/utilities): Color tools, number converters, and handy utilities. 6 tools.
- [Network & API](https://devtoolbox.cloud/categories/network-api): DNS lookup, API testing, and network analysis tools. 17 tools.
- [Data & Productivity](https://devtoolbox.cloud/categories/data-productivity): Generate data, manage passwords, and boost productivity. 14 tools.
- [String Tools](https://devtoolbox.cloud/categories/string-tools): Transform, inspect, and manipulate text strings. 4 tools.
- [SVG & Image](https://devtoolbox.cloud/categories/svg-image): Extract, optimize, and process SVGs and images. 6 tools.

## Optional

The remaining 85 tools, for agents that want the whole catalogue. A concatenated copy of every page's content is at [llms-full.txt](https://devtoolbox.cloud/llms-full.txt).

### Beautifiers & Formatters

- [Code Beautifier](https://devtoolbox.cloud/code-beautifier): Beautify JSON, GraphQL & SQL.
- [HTML Beautifier](https://devtoolbox.cloud/html-beautifier): Beautify & minify HTML.
- [CSS Beautifier](https://devtoolbox.cloud/css-beautifier): Beautify & minify CSS.
- [JS Beautifier](https://devtoolbox.cloud/js-beautifier): Beautify & minify JavaScript.
- [ERB Beautifier](https://devtoolbox.cloud/erb-beautifier): Beautify & minify ERB templates.
- [LESS Beautifier](https://devtoolbox.cloud/less-beautifier): Beautify & minify LESS.
- [SCSS Beautifier](https://devtoolbox.cloud/scss-beautifier): Beautify & minify SCSS.
- [SQL Formatter](https://devtoolbox.cloud/sql-formatter): Format raw SQL queries.
- [XML Formatter](https://devtoolbox.cloud/xml-formatter): Format & validate XML.
- [TOML Formatter](https://devtoolbox.cloud/toml-formatter): Format TOML files.
- [HTML Validator](https://devtoolbox.cloud/html-validator): Validate HTML markup.
- [YAML Validator](https://devtoolbox.cloud/yaml-validator): Validate YAML syntax.
- [Markdown → HTML](https://devtoolbox.cloud/markdown-html): Convert Markdown to HTML.
- [HTML Preview](https://devtoolbox.cloud/html-preview): Live HTML/CSS/JS preview.

### Encoders & Converters

- [URL Encoder](https://devtoolbox.cloud/url-encoder): Encode & decode URLs.
- [HTML Entities](https://devtoolbox.cloud/html-entities): Encode & decode entities.
- [JSON / CSV](https://devtoolbox.cloud/json-csv): Convert JSON ↔ CSV.
- [YAML / JSON](https://devtoolbox.cloud/yaml-json): Convert YAML ↔ JSON.
- [Docker Compose](https://devtoolbox.cloud/docker-compose): Docker run → Compose & K8s.
- [JSON to Schema](https://devtoolbox.cloud/json-schema): JSON → Prisma, TS, SQL, Go.
- [TOML to JSON](https://devtoolbox.cloud/toml-to-json): Convert TOML ↔ JSON.
- [TOML to YAML](https://devtoolbox.cloud/toml-to-yaml): Convert TOML ↔ YAML.
- [SVG to CSS](https://devtoolbox.cloud/svg-to-css): SVG to CSS background.
- [Backslash Escape](https://devtoolbox.cloud/backslash-escape): Escape & unescape strings.
- [UUID Generator](https://devtoolbox.cloud/uuid-generator): Generate & decode UUIDs.

### Testing & Analysis

- [Log Parser](https://devtoolbox.cloud/log-parser): Parse & filter log files.
- [Request Tester](https://devtoolbox.cloud/request-tester): Test HTTP requests.
- [Script Runner](https://devtoolbox.cloud/script-runner): Run JavaScript & see output.

### Time & Date

- [Timestamp](https://devtoolbox.cloud/timestamp-converter): Unix ↔ human dates.
- [Cron Generator](https://devtoolbox.cloud/cron-generator): Build cron expressions.
- [Cron Explainer](https://devtoolbox.cloud/cron-explainer): Explain cron in plain English.
- [Timer](https://devtoolbox.cloud/timer): Focus & break Pomodoro timer.
- [Date Calculator](https://devtoolbox.cloud/date-calculator): Add/subtract dates & find differences.
- [Timezone Converter](https://devtoolbox.cloud/timezone-converter): Convert between timezones.
- [Duration Converter](https://devtoolbox.cloud/duration-converter): Convert time durations.
- [ISO 8601 Parser](https://devtoolbox.cloud/iso-parser): Parse ISO 8601 date strings.
- [Age Calculator](https://devtoolbox.cloud/age-calculator): Calculate age from birthdate.
- [World Clock](https://devtoolbox.cloud/world-clock): Multiple timezone clocks.

### Utilities

- [Color Converter](https://devtoolbox.cloud/color-converter): Convert color formats.
- [Color Picker](https://devtoolbox.cloud/color-picker): Pick colors with palettes.
- [Color Contrast Checker](https://devtoolbox.cloud/color-contrast): WCAG contrast ratio checker.
- [CSS Cursors](https://devtoolbox.cloud/css-cursors): Visual CSS cursor reference.
- [Number Converter](https://devtoolbox.cloud/number-converter): Dec, hex, bin, oct.
- [Unit Converter](https://devtoolbox.cloud/unit-converter): Convert measurements.

### Network & API

- [DNS Lookup](https://devtoolbox.cloud/dns-lookup): Query DNS records.
- [SSL Checker](https://devtoolbox.cloud/ssl-checker): Check SSL certificates.
- [What Is My IP](https://devtoolbox.cloud/whats-my-ip): Public IP & location.
- [HTTP Status Codes](https://devtoolbox.cloud/http-status): HTTP code reference.
- [Socket Client](https://devtoolbox.cloud/socket-client): WebSocket tester.
- [System Checker](https://devtoolbox.cloud/system-checker): Device & browser info.
- [Curl Command Generator](https://devtoolbox.cloud/curl-generator): Build curl commands visually.
- [CORS Explainer](https://devtoolbox.cloud/cors-explainer): Interactive CORS scenario debugger.
- [HTTP Status Tester](https://devtoolbox.cloud/http-status-tester): Test & explore HTTP status codes.
- [MIME Type Lookup](https://devtoolbox.cloud/mime-lookup): Search MIME types & content-types.
- [API Tester](https://devtoolbox.cloud/api-tester): Postman-like API testing tool.
- [URL Parser](https://devtoolbox.cloud/url-parser): Parse & edit URL components.
- [User Agent Parser](https://devtoolbox.cloud/user-agent-parser): Parse browser user agents.
- [Subnet Calculator](https://devtoolbox.cloud/subnet-calculator): IPv4 subnet calculations.
- [IP Subnet Divider](https://devtoolbox.cloud/ip-subnet-divider): Divide networks into subnets.
- [Port Reference](https://devtoolbox.cloud/port-reference): TCP/UDP port lookup.
- [MAC Address Lookup](https://devtoolbox.cloud/mac-lookup): Identify MAC address vendor.

### Data & Productivity

- [JSON Path Finder](https://devtoolbox.cloud/json-path): Navigate JSON structures.
- [Paste Bin](https://devtoolbox.cloud/paste-bin): Share text via encoded links.
- [Hash Generator](https://devtoolbox.cloud/hash-generator): MD5, SHA-1, SHA-256 & more.
- [Password Generator](https://devtoolbox.cloud/password-generator): Secure random passwords.
- [QR Code Generator](https://devtoolbox.cloud/qr-generator): Generate QR codes.
- [Fake Data](https://devtoolbox.cloud/fake-data): Generate mock JSON data.
- [Relational Data](https://devtoolbox.cloud/relational-data): Visual relational data builder.
- [Structured Data](https://devtoolbox.cloud/structured-data): Generate structured dummy data.
- [GZIP & Brotli](https://devtoolbox.cloud/compressor): Compress & compare formats.
- [ULID Generator](https://devtoolbox.cloud/ulid-generator): Generate sortable ULIDs.
- [RSA Key Pair](https://devtoolbox.cloud/rsa-generator): Generate RSA key pairs.
- [Lorem Ipsum](https://devtoolbox.cloud/lorem-ipsum): Generate lorem ipsum text.
- [Online Notepad](https://devtoolbox.cloud/notepad): Multi-tab code editor in browser.
- [CSV Preview](https://devtoolbox.cloud/csv-preview): Preview CSV in a sortable table.

### String Tools

- [Case Converter](https://devtoolbox.cloud/string-case): Convert string cases.
- [String Inspector](https://devtoolbox.cloud/string-inspector): Analyze text details.
- [String Replacer](https://devtoolbox.cloud/string-replacer): Find & replace text.
- [ASCII Art](https://devtoolbox.cloud/ascii-art): ASCII art text generator.

### SVG & Image

- [SVG Extractor](https://devtoolbox.cloud/svg-extractor): Extract SVGs from HTML.
- [SVG Optimizer](https://devtoolbox.cloud/svg-optimizer): Optimize & minify SVGs.
- [Placeholder Image](https://devtoolbox.cloud/placeholder-image): Generate placeholder images.
- [QR Scanner](https://devtoolbox.cloud/qr-scanner): Scan QR codes via camera.
- [Favicon Generator](https://devtoolbox.cloud/favicon-generator): Create favicons from text or images.
- [Batch Image Processor](https://devtoolbox.cloud/batch-image-processor): Batch resize & convert images.