Is the JSON Formatter safe for sensitive data?

Yes. JSON Formatter and Validator runs completely in your browser, so the data you paste—API responses, configs, or payloads—never reaches a server. You can pretty-print, minify, and validate JSON for syntax errors knowing that nothing leaves your machine.

Can I test a regular expression here?

Yes. Regex Tester lets you write a pattern and see matches highlighted against your sample text in real time, with capture groups broken out. It helps you debug expressions for validation, search, and replace before you drop them into your code.

What can I do with the Base64 tool?

Base64 Encoder and Decoder converts text and files to and from Base64, which is useful for embedding images in CSS, inspecting tokens, or moving binary data through text-only channels. It encodes and decodes instantly in your browser without uploading anything.

Does the JWT Decoder verify signatures?

JWT Decoder reads a token and shows its header and payload as readable JSON so you can inspect claims like expiry and issuer. It decodes locally in your browser and is meant for inspection and debugging rather than verifying a signature against a secret key.

Are these developer tools free with no sign-up?

Yes. All of the developer utilities are free and require no account. Format JSON, generate UUIDs and hashes, decode tokens, convert timestamps, and more—each tool runs in your browser, so it is fast and your data stays private.

Developer Tools

95 tools

Free online developer tools — fast, private, and easy to use. No sign-up required.

Showing 95 of 95

JSON Formatter & Validator

Format, validate, and minify JSON instantly. Includes syntax highlighting, error detection, and a collapsible tree view — free, private, in-browser.

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Regex Tester

Test and debug regular expressions online. See live matches, capture groups, and replace output. Free, private, instant.

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Base64 Encoder & Decoder

Encode text or files to Base64, or decode Base64 strings back to text in seconds. Free, private, and fully in-browser now.

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URL Encoder / Decoder

Encode and decode URLs and URL components online. Convert special characters to percent-encoding and back instantly — free, private, and fast.

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HTML Encoder / Decoder

Encode and decode HTML entities online. Escape <, >, &, and quote characters for safe HTML display. Free, instant, and private — runs in your browser.

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Hash Generator

Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes instantly in your browser. Free, private, and secure for quick checks.

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Number Base Converter

Convert numbers between binary, octal, decimal, and hexadecimal instantly. Essential tool for programmers and developers.

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UUID Generator

Generate random UUID v4, timestamp-based UUID v1, and ULID identifiers. Bulk-generate up to 100 at once and copy them instantly — free and private.

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JWT Decoder

Decode and inspect JSON Web Tokens (JWT) online. View header, payload, and expiry. 100% client-side — your token never leaves your browser.

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Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. Shows UTC, local, and ISO 8601 formats.

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JSON to CSV Converter

Convert JSON arrays to CSV format online. Supports nested objects, custom delimiters, and CSV to JSON conversion. Free and private.

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Meta Tag Generator

Generate SEO meta tags, Open Graph tags, and Twitter Card tags online. Preview Google search snippet and copy all tags instantly.

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XML Sitemap Generator

Generate a valid XML sitemap for your website. Add your URLs, set change frequency and priority, then download the sitemap.xml.

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CSS Minifier & Beautifier

Minify and beautify CSS code online. Reduce CSS file size by removing whitespace and comments. Free online CSS minifier with instant results.

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YAML ↔ JSON Converter

Convert YAML to JSON and JSON to YAML online. Validate syntax instantly with error messages. Free, private converter that runs in your browser.

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SQL Formatter

Format and beautify SQL queries online. Adds line breaks, indentation, and keyword casing for readable queries. Free SQL beautifier in your browser.

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Cron Expression Generator

Build and decode cron expressions online. Get a plain-English description of any crontab schedule and a field-by-field breakdown. Free cron generator.

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JSON to TypeScript Types

Convert JSON to TypeScript interfaces online. Infers types, nested objects, and arrays automatically. Free, private JSON-to-TS generator in your browser.

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XML Formatter

Format and beautify XML online with proper indentation. Pretty print or minify XML and validate basic structure. Free XML formatter in your browser.

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Slug Generator

Convert any text or title into a clean URL slug. Lowercases, removes accents and special characters, and joins words with hyphens. Free slugify tool.

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Chmod Calculator

Calculate Unix file permissions with an interactive chmod calculator. Convert between octal (755) and symbolic (rwxr-xr-x) notation instantly. Free online.

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.gitignore Generator

Generate a .gitignore file for your project. Pick languages, frameworks, and tools to build a ready-to-use git ignore file. Free and private.

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cURL Converter

Convert a curl command to JavaScript fetch, Node, Python requests, or PHP. Paste your curl and get clean client code instantly. Free and private.

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Bcrypt Hash Generator & Checker

Generate bcrypt password hashes and verify a password against a hash online. Adjustable cost factor. Free, private bcrypt tool in your browser.

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TOTP / 2FA Code Generator

Generate time-based one-time passwords (TOTP) from a secret key online. Compatible with Google Authenticator and 2FA. Free, private TOTP generator.

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robots.txt Generator

Generate a robots.txt file for your website. Set user-agents, allow/disallow rules, crawl-delay, and sitemap URL. Free, private robots.txt builder.

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.htaccess Redirect Generator

Generate .htaccess redirect rules online. Create 301/302 redirects, www and HTTPS forcing, and RewriteRule snippets for Apache. Free and private.

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JSON Schema Validator

Validate JSON data against a JSON Schema online. Get clear, path-based error messages for every violation. Free, private JSON Schema validator.

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HMAC Generator

Generate HMAC signatures with SHA-1, SHA-256, SHA-384, or SHA-512 and a secret key. Uses the Web Crypto API. Free and private.

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AES Encrypt / Decrypt

Encrypt and decrypt text with AES-256-GCM and a password. Strong, standards-based encryption in your browser. Free and private.

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Password Strength Tester

Test how strong a password is with an entropy score and estimated crack time. Get tips to improve it. Runs locally — Free and private.

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User Agent Parser

Parse any user-agent string to identify the browser, engine, operating system, and device. Detects your own UA too. Free and private.

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HTTP Status Codes

A searchable reference of all HTTP status codes with meanings and when to use them — 1xx to 5xx. Free, fast, and private.

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JSON ↔ XML Converter

Convert JSON to XML and XML to JSON with formatting. Validate and transform structured data both ways. Free, private, in-browser.

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PX ↔ REM Converter

Convert px to rem and rem to px for responsive CSS, with a configurable root font size. Includes a handy reference table. Free and private.

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RSA Key Generator

Generate an RSA public/private key pair in PEM format (2048 or 4096-bit) using the Web Crypto API. Free, private, in-browser.

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MAC Address Generator

Generate random MAC addresses in any format, with optional vendor (OUI) prefixes. Bulk generation supported. Free and private.

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HTML ↔ Markdown

Convert HTML to clean Markdown and Markdown to HTML. Paste content and switch formats with a live preview. Free, private, in-browser.

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API Tester (Online REST Client)

Build and send HTTP requests with method, URL, headers, auth, and JSON body, then inspect status, timing, headers, and response payload in one browser tool.

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Base64 Chunker

Split any Base64 string or file into fixed-size numbered chunks with sequence metadata. Export JSON or line format for multipart uploads, fully in browser.

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Base64 Payload Extractor

Paste a JSON body, HTML source, or any text and automatically extract all embedded base64 data URIs. Preview, inspect, and download each artifact — fully in-browser.

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Base64 Reassembler

Paste numbered Base64 chunks (JSON or line format) to validate order, detect corruption, and rebuild the original Base64 string with clear per-chunk errors.

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Basic Auth Header Generator

Generate an HTTP Basic Authentication header from a username and password. Get the Base64 Authorization value and a curl snippet, encoded in your browser.

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Code Beautifier & Formatter

Format and beautify code online with Prettier. Supports JavaScript, TypeScript, JSON, CSS, HTML, Markdown, YAML, and more. Free, private, runs in your browser.

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CORS Tester / Preflight Checker

Run a real preflight and follow-up request against any endpoint, then verify Access-Control headers for origin, methods, headers, and credentials.

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Crontab Expression Generator & Explainer

Generate valid 5-field crontab expressions with a visual builder, decode existing cron syntax, and preview the next five local run times with clear validation.

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Data URI to File

Paste any data URI and instantly decode it to a downloadable file. Supports all MIME types — images, PDFs, audio, JSON, and more. Runs entirely in your browser.

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docker run to docker-compose

Convert a docker run command into a docker-compose.yml service. Parses ports, env vars, volumes, restart, networks and more — instant and private in your browser.

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.env ↔ JSON Converter

Convert a .env (dotenv) file to JSON, or JSON to .env. Handles quoted values, comments and export prefixes. Runs privately in your browser.

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File to Data URI

Upload any file and get a standards-compliant data URI instantly. Includes raw Base64, URL-safe Base64, and the full data URI — all in-browser and private.

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GraphQL Query Tester

Test GraphQL endpoints with query, variables, and headers, inspect data/errors, and explore introspection schema in-browser, with proxy fallback for CORS.

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HAR File Viewer

Open and inspect HAR files in your browser with waterfall timing, filters, and per-request details to debug web performance and API behavior without uploads.

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Hreflang Tag Generator

Generate hreflang link tags for multilingual websites. Validate ISO language and region codes, catch duplicates, and copy HTML, HTTP header, or XML sitemap output.

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HTML Minifier

Minify HTML to reduce file size: remove comments, collapse whitespace and strip empty attributes while preserving pre, script and style blocks — all in your browser.

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htpasswd Generator

Generate Apache .htpasswd entries online with bcrypt or SHA-1. Enter a username and password to get a ready-to-paste line. Free, private, and runs in your browser.

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HTTP Debug & Test Endpoints

Test real HTTP clients against permanent debug endpoints for status codes, echo payloads, redirects, headers, gzip, and SSE from one base URL.

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HTTP Status Code Reference

A complete, searchable reference of HTTP status codes from 1xx to 5xx, each with its name, meaning, and an http.cat illustration. Free and usable offline.

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JavaScript Minifier

Minify and compress JavaScript online with Terser. Remove whitespace, comments, and dead code, and optionally mangle names to shrink your JS. Free and private.

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JSON Escape / Unescape

Escape or unescape JSON strings online. Turn text into a safe JSON string literal, or decode an escaped string back to plain text. Free and in-browser.

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JSON to Go Struct

Convert JSON into Go structs with json tags. Generates nested types, slices and correct Go types from any JSON sample. Free, instant, runs in your browser.

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JWT Generator (HS256/384/512)

Create and verify HS256, HS384, and HS512 JSON Web Tokens with claim presets, base64 secret support, and round-trip signature checks entirely in-browser.

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JavaScript Keycode Info

Press any key to see its JavaScript event.key, event.code and keyCode values live. A keyboard event inspector and keycode reference that runs in your browser.

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MIME Type Lookup

Look up the MIME type for any file extension, or find which extensions map to a MIME type. Covers images, video, audio, docs, fonts and archives. In-browser.

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Mock API Endpoint Generator

Generate a temporary mock API endpoint with custom status, headers, body, latency, and CORS, then edit it live and inspect hits before 72-hour expiry.

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Nginx Config Generator

Generate an nginx server block for static sites, SPAs or reverse proxies. Toggle HTTPS redirect, gzip and www, then copy a ready-to-use config — all in your browser.

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npm Package Inspector

Look up any npm package to see its latest version, description, license, homepage, repository, last-published date, and keywords. Free, instant npm data.

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OAuth Callback / Redirect URI Tester

Capture and inspect OAuth redirect_uri query and fragment parameters, decode JWT token claims, and test PKCE/state values entirely in your browser.

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Query String ↔ JSON

Parse a URL query string into JSON, or build a query string from JSON. Handles repeated keys as arrays and URL-encoding. Free, instant, in-browser.

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Schema Markup Generator (JSON-LD)

Generate valid JSON-LD structured data for Article, FAQ, HowTo, LocalBusiness, Product, and Breadcrumb schemas. Free, instant, and fully in-browser.

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Google SERP Snippet Preview

Preview how your page title, meta description, and URL appear in Google search results. Check pixel widths, spot truncation, and fix snippets fast.

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XML Sitemap Validator

Validate any XML sitemap online. Check structure, namespace, URL count, lastmod dates, and size limits, and list child sitemaps - enter a URL for a full report.

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Snowflake ID Decoder

Decode Discord and Twitter/X snowflake IDs into exact creation time, worker, process, and increment bits, or generate the minimum ID for a chosen timestamp.

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SSE / EventSource Tester

Connect to any HTTP/S EventSource URL, inspect named events and lastEventId values, and debug stream behavior with local logging and CORS guidance.

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String Escape / Unescape

Escape or unescape strings for JavaScript, Java, C/C++, JSON, SQL, CSV and shell. Safely embed quotes and special characters, processed in your browser.

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TOML ↔ JSON Converter

Convert TOML to JSON and JSON to TOML online. Paste a config file to transform it in either direction instantly. Free, private converter that runs in your browser.

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Truth Table Generator

Generate a truth table from any boolean expression. Supports AND, OR, NOT, XOR, NAND, NOR, XNOR and parentheses with up to 8 variables — runs in your browser.

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ULID Generator

Generate ULIDs online — time-ordered, URL-safe, sortable alternatives to UUIDs. Bulk generate and decode the embedded timestamp, all in your browser.

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Unicode Escape / Unescape

Escape text to Unicode sequences (\uXXXX, HTML &#x; entities, CSS \HH) or unescape them back to readable characters. Free, instant, in your browser.

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Webhook Signature Verifier

Verify Stripe, GitHub, Shopify, Slack, and generic HMAC webhook signatures with timestamp tolerance checks entirely in your browser.

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Webhook Tester

Create a unique webhook URL, inspect requests live, copy payloads as cURL, and return custom responses with delay. Bin data auto-expires after 24 hours.

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WebSocket Tester

Connect to any ws:// or wss:// endpoint, send and inspect frames with timestamps and byte sizes, auto-reconnect, and keep saved targets locally in your browser.

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HTML to Text Converter

Strip HTML tags and convert markup to clean plain text online. Paste HTML and get readable text with whitespace tidied — free, private, and in your browser.

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HTML Viewer & Previewer

Paste HTML and preview the rendered result instantly in a safe sandbox. Toggle between rendered output and formatted source — free, private, and in your browser.

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HTML Table Generator

Build clean, semantic HTML tables visually. Set rows and columns, fill cells, toggle a header row, and copy ready-to-use HTML — free and in your browser.

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Table to HTML Converter

Paste CSV, TSV, or spreadsheet data and convert it to a clean HTML table instantly. Choose a delimiter and header row, then copy the markup — free and private.

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Meta Tag Generator

Generate SEO, Open Graph, and Twitter Card meta tags from a simple form. Add your title, description, and image, then copy the ready-to-paste HTML for your head.

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SVG Viewer & Inspector

Paste or upload SVG code and preview it instantly with size, viewBox, and element details. Inspect and check vector graphics in your browser — free and private.

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Code to Image Generator

Turn code snippets into clean, shareable PNG images. Paste your code, pick a theme, then download a picture for slides, docs, or social — free and private.

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README Generator

Fill in a short form and generate a clean, GitHub-ready README.md with a title, badge, overview, features, install, usage, and license sections. Free and private.

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Git Commit Message Generator

Build a properly formatted Conventional Commit message from a type, scope, description, body, and breaking-change footer. Free, private, and instant.

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OpenAPI Viewer

Paste an OpenAPI or Swagger spec in JSON or YAML to see a searchable, colour-coded list of every endpoint and method. Runs entirely in your browser.

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JSON Diff Checker

Compare two JSON documents structurally for a path-by-path list of what was added, removed, or changed — objects and arrays, not raw text. Free and private.

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Open Source License Picker

Answer a few questions to get a recommended open-source license — MIT, Apache-2.0, BSD-3, GPL-3.0, or MPL-2.0 — with copyable LICENSE text. Free and private.

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UUID Validator

Validate a UUID and inspect its version and variant, with nil-UUID detection and case/brace normalization. Free, private, and instant in your browser.

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URL Parser

Break a URL into its protocol, hostname, port, path, query parameters, and hash, with decoded parameter values. Free, private, and instant in your browser.

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Popular Developer Tools

Often used together

About Developer Tools

Developers reach for the same small utilities dozens of times a day: pretty-printing a JSON response, testing a regular expression, encoding a string, or decoding a token to see what is inside it. ToolsHub turns those daily-driver tasks into instant, no-friction pages so you can stay in flow instead of hunting for a sketchy site or wiring up a throwaway script.

The headline tools cover the basics you lean on most. JSON Formatter and Validator cleans up and checks payloads, Regex Tester highlights matches against your sample text, and Base64 Encoder and Decoder handles text and files. URL Encoder, HTML Encoder, Hash Generator, and the Number Base Converter round out the everyday set, while UUID Generator and Unix Timestamp Converter take care of identifiers and time.

There is depth for bigger jobs too. Convert JSON to CSV or TypeScript types, swap between YAML, XML, and JSON, format SQL, and minify or beautify CSS. JWT Decoder inspects token claims, and security helpers like Bcrypt, HMAC, TOTP, AES Encrypt/Decrypt, and the Password Strength Tester are on hand. For web and ops work, you can generate meta tags, sitemaps, robots.txt, .gitignore files, cron expressions, and .htaccess redirects.

Because each tool runs entirely in your browser, the data you paste—API responses, configs, secrets, and tokens—never reaches a server and is never stored. That makes them safe for work you cannot send to a third party, and they are free with no account required. Pick a tool, paste your input, and copy the result, all without leaving the page.