Free Developer Tools for APIs, JSON, SQL and Debugging
Use free online developer tools for JSON formatting, JWT decoding, SQL formatting, HTTP status codes, webhooks, cron expressions, API debugging, and backend workflows.
Best Developer Tools to Start With
Curated entry points for the strongest developer workflows.
JSON Tree Viewer
Visualize JSON data in an interactive tree structure.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT) without validation.
SQL Formatter
Format, minify, convert, compare, and analyze SQL queries in a private browser-based SQL formatter with MySQL and PostgreSQL workflow tools.
HTTP Status Code Reference
Searchable reference for all HTTP status codes — with meaning, common causes, and fix recommendations.
Webhook Tester
Receive, inspect, and debug incoming webhooks in real-time — see headers, body, query params, and method for any HTTP request sent to your unique endpoint.
JSON to TypeScript Interface
Convert any JSON object into TypeScript interfaces instantly — handles nested objects, arrays, union types, optional fields, and generics.
Developer Tools by Use Case
Browse tools grouped by what you need to get done.
JSON and API Tools
Clean copied API responses, inspect nested payloads, test JSON paths, and convert response data into TypeScript interfaces for frontend or backend development.
JSON Formatter
Format, validate, and beautify JSON instantly — with clear error messages, Tree View, Diff mode, and Schema validation.
JSON Tree Viewer
Visualize JSON data in an interactive tree structure.
JSON Path Tester
Test JSONPath expressions against your JSON.
JSON to TypeScript Interface
Convert any JSON object into TypeScript interfaces instantly — handles nested objects, arrays, union types, optional fields, and generics.
Authentication and Tokens
Inspect token headers and payloads when debugging auth flows. Use Base64 to decode encoded strings. Do not paste live production tokens into any online tool.
SQL and Backend Debugging
Clean unreadable queries, format messy JavaScript and HTML output from APIs, and prepare code for documentation or code review.
Webhooks, Status Codes and Testing
Test integrations, check webhook payloads, understand HTTP responses, and validate cron schedules without setting up a full local environment.
Webhook Tester
Receive, inspect, and debug incoming webhooks in real-time — see headers, body, query params, and method for any HTTP request sent to your unique endpoint.
HTTP Status Code Reference
Searchable reference for all HTTP status codes — with meaning, common causes, and fix recommendations.
Cron Expression Generator
Build and decode cron schedule expressions visually — get human-readable descriptions and next run times.
Encoding, IDs and Time
Small backend tasks often involve encoded values, IDs, timestamps, and URL-safe strings. Decode, encode, generate, and inspect those values quickly.
Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 to plain text — with URL-safe mode, auto-detect, and size stats.
URL Encoder/Decoder
Encode and decode URL strings with special characters.
UUID Generator
Generate random UUID v4 identifiers instantly — single or bulk, with format options.
Unix Timestamp Converter
Convert Unix epoch timestamps to human-readable dates and vice versa — with timezone support.
Markdown and Documentation Tools
Write, preview, convert, and format Markdown for README files, documentation, changelogs, and technical notes. Preview rendered output with live GitHub Flavored Markdown support, generate clean tables, convert between Markdown and HTML, and normalize Markdown style before committing.
Markdown Viewer
Write, preview, copy, import, export, and print Markdown in a private browser-based Markdown viewer with live GitHub Flavored Markdown preview.
Markdown to HTML Converter
Convert Markdown to clean, semantic HTML with live preview — GFM tables and task lists, heading IDs, a table of contents generator, four output modes, and HTML sanitization.
Markdown Table Generator
Create, format, and validate GFM Markdown tables visually — Smart Paste auto-detects CSV, spreadsheet, or existing Markdown, flags broken tables, and lets you copy or download clean output.
Markdown Formatter
Clean messy Markdown for READMEs, docs, blog drafts, and AI-generated content. Normalize headings, lists, emphasis, and tables with safe protected-zone formatting.
All Developer Tools
207 free tools — no sign-up required.
301 Redirect Code Generator
Generate redirect code for Apache (.htaccess), Nginx, IIS (web.config), PHP, HTML meta refresh, and JavaScript. Supports 301, 302, 307, and 308 status codes.
AI Tools
A practical AI workflow reference with prompt templates, evaluation checks, developer use cases, and anti-patterns.
All Number Converter
Convert between all four number bases — binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) — in one tool.
AND Calculator
Calculate the bitwise AND of two numbers with decimal, binary, hex, and octal input/output — includes a visual bit-by-bit breakdown.
Angle Converter
Convert angle units between degrees, radians, gradians, turns, arcminutes, and arcseconds.
Angular Formatter
Format Angular templates and component snippets with clean indentation for easier reading, review, and debugging.
Area Converter
Convert area units between square meters, square feet, acres, hectares, square miles, and more.
Astronomical Converter
Convert astronomical distances between AU, light-years, parsecs, light-seconds, lunar distances, and more.
Avro Formatter
Format Apache Avro schema JSON with indentation, validation feedback, schema stats, copy, and download.
Babel Formatter
Format Babel and modern JavaScript snippets with readable indentation for debugging transformed code.
BBCode Editor
Write BBCode with a formatting toolbar and see a live rendered preview. Supports bold, italic, links, images, quotes, code blocks, lists, and more.
BBCode Viewer
Paste BBCode and instantly see how it renders as HTML. Toggle between the visual preview and the raw HTML source. Great for checking posts before submitting.
Bitwise Calculator
Calculate all bitwise operations — AND, OR, XOR, NAND, NOR, XNOR — with decimal, binary, hex, and octal input and output.
Bytes Converter
Convert digital storage units between bits, bytes, KB, KiB, MB, MiB, GB, GiB, TB, and TiB.
C Beautifier
Beautify C source snippets by expanding braces and statements into readable, consistently indented code.
Cash App Fees Calculator
Calculate Cash App transaction fees for credit card payments, business receipts, and instant bank transfers — see fee and net amount side by side.
Checksum Calculator
Calculate CRC-32, Adler-32, MD5, SHA-1, SHA-256, SHA-384, and SHA-512 checksums from text, hex, or Base64 input.
CIDR Calculator
Calculate subnet details from a CIDR notation — network address, broadcast, first/last host, usable hosts, subnet mask, and binary representation.
Code Highlighter
Paste code in JavaScript, TypeScript, Python, HTML, CSS, SQL, JSON, or Bash and get a syntax-highlighted HTML snippet you can embed anywhere. Live preview and copy-ready output.
Code to Image Converter
Convert code snippets to beautiful images for sharing.
C++ Beautifier
Beautify C++ source by expanding braces, loops, and statements into readable, consistently indented code.
Credit Card Validator
Validate credit card number structure with brand detection, length checks, masking, and the Luhn checksum. Runs entirely in your browser.
Cron Expression Explainer
Translate cron expressions to plain English — see next run times, validate schedules, and learn cron syntax with live examples.
Cron Expression Generator
Build and decode cron schedule expressions visually — get human-readable descriptions and next run times.
C# Beautifier
Beautify C# classes, methods, properties, and control-flow snippets with clean indentation.
C# Escape / Unescape
Escape or unescape text for C# string literals in your browser. Free, no signup, runs locally.
Density Converter
Convert density units between kg/m^3, g/cm^3, g/L, kg/L, lb/ft^3, lb/in^3, and lb/gal.
DNS Lookup Tool
Query A, AAAA, MX, TXT, CNAME, NS, and SOA DNS records globally using Cloudflare DoH — for email, SSL, and domain debugging.
Electric Current Converter
Convert electric current units between A, mA, uA, nA, kA, and MA with adjustable precision.
Encryption Decryption
Encrypt and decrypt text locally with password-based AES-GCM encryption and a portable JSON envelope.
Energy Converter
Convert energy units between J, kJ, cal, kcal, Wh, kWh, BTU, eV, and ft-lb.
Unix Timestamp Converter
Convert Unix epoch timestamps to human-readable dates and vice versa — with timezone support.
Force Converter
Convert force units between N, kN, dyn, kgf, lbf, ozf, pdl, and kip.
HTML Form Builder
Build HTML forms visually, edit fields and attributes, preview the form, and copy generated markup.
Frequency Converter
Convert frequency units between Hz, kHz, MHz, GHz, CPM, RPM, BPM, and rad/s.
Fuel Converter
Convert fuel economy and fuel consumption units between mpg, km/L, L/100 km, and gallons per 100 miles.
Full Black Screen
Open a pure black screen for monitor checks, OLED testing, focus lighting, and display inspection.
Full Blue Screen
Open a pure blue screen for display checks, chroma-style backdrops, and solid color testing.
Full Red Screen
Open a pure red screen for monitor checks, red-channel testing, and solid color display use.
Full White Screen
Open a pure white screen for monitor checks, cleaning light, brightness tests, and display inspection.
GraphQL Beautifier
Beautify GraphQL queries, mutations, and schemas with consistent indentation, one field per line, and tidy selection sets.
GZip Decompress Online
Decompress Base64, hex, or binary GZip data into readable text directly in your browser.
HMAC Generator
Generate HMAC signatures with SHA-1, SHA-256, SHA-384, or SHA-512 from text, hex, or Base64 input.
Hostname to IP
Find the IPv4 and IPv6 addresses behind a hostname using DNS A and AAAA records.
HTML Audio Generator
Generate HTML <audio> elements with multiple source formats, controls, autoplay, loop, muted, and preload options. Copy ready-to-use code instantly.
HTML BDO Generator
Generate HTML <bdo> (bidirectional override) elements to control text direction. Set dir to rtl or ltr with optional id, class, and title attributes.
HTML Beautifier
Format and beautify minified or messy HTML code.
HTML Blockquote Generator
Generate HTML blockquote elements with quote text, citation URL, attribution, and optional figure/figcaption semantic wrapper.
HTML Button Generator
Generate HTML button elements with type, id, class, style, onclick, disabled, aria-label, and other attributes. Preview included.
HTML Canvas Generator
Generate HTML <canvas> elements with configurable width, height, id, and class. Includes optional JavaScript 2D context starter code for drawing.
HTML Checkbox Generator
Generate HTML checkbox input elements with label, id, name, value, checked, disabled, and required attributes. Includes live preview.
HTML Citation Generator
Generate HTML <cite> elements to mark titles of creative works — books, films, articles, and more. Optionally wrap in a link. Live preview included.
HTML Cleaner
Clean messy HTML by removing inline styles, scripts, comments, empty tags, Word markup, class and data attributes.
HTML Code Generator
Generate HTML <pre><code> code blocks with language class for Prism and Highlight.js syntax highlighting. Live preview and one-click copy.
HTML Code Tag Generator
Generate HTML <code> inline code elements for embedding short code snippets within prose. Configure id, class, title, and lang attributes. Live preview.
HTML Color Input Generator
Generate HTML <input type="color"> code with live preview. Customise id, name, default colour, label, and more.
HTML Compressor
Compress and minify HTML by removing comments, collapsing whitespace, stripping empty attributes, and removing optional tags. Shows byte savings.
HTML Date & Time Input Generator
Generate HTML date, time, datetime-local, month, and week input elements with min, max, value, label, required, and disabled attributes.
HTML Details/Summary Generator
Generate HTML details and summary elements for native accordion/disclosure widgets. Configure summary text, content, open state, id, and class.
HTML Dialog Generator
Generate HTML dialog elements with title, body, close button, footer actions, and the JavaScript snippet to open it as a modal.
HTML Email Input Generator
Generate HTML email input elements with placeholder, autocomplete, multiple, required, disabled, and label attributes. Live preview included.
HTML Emphasize Text Generator
Generate HTML <em> (emphasize) elements with optional id, class, title, and lang attributes. Adds semantic stress emphasis to inline text. Live preview included.
HTML Escape / Unescape
Escape and unescape HTML special characters (&, <, >, ", ') on a single page.
HTML Fieldset Generator
Generate HTML <fieldset> elements with <legend> for grouping related form controls. Configure legend text, disabled state, and optional form, id, and class attributes.
HTML Figure Generator
Generate HTML <figure> and <figcaption> elements for images with accessible markup. Configure image source, alt text, caption position, and optional styling.
HTML File Input Generator
Generate HTML file input elements with accept type presets, multiple file selection, capture attribute for mobile cameras, required, and label. Live preview included.
HTML iFrame Generator
Generate HTML iframe markup with src, width, height, sandbox, referrer policy, loading, and allow attributes. Includes a live preview.
HTML Image Input Generator
Generate <input type="image"> markup with src, alt, sizing, form override attributes, and live preview. Builds an image-based submit button.
HTML Link Generator
Generate HTML anchor tags with href, target, rel, title, download, and other attributes. Copy ready-to-use link code instantly.
HTML Mark Text Generator
Generate HTML <mark> elements to highlight text for reference or search result emphasis. Configure id, class, and title attributes. Live preview included.
HTML Meta Tags Generator
Generate SEO and social meta tags including Open Graph, Twitter Card, charset, viewport, description, and canonical URL.
HTML Meter Generator
Generate HTML <meter> element code with value, min, max, low, high, and optimum settings. Live preview included.
HTML Minifier
Compress HTML by removing whitespace, comments, and redundant attributes — with size reduction stats.
HTML Number Input Generator
Generate HTML number input elements with min, max, step, placeholder, value, label, and other attributes. Includes live preview.
HTML Password Input Generator
Generate HTML password input elements with minlength, maxlength, pattern, autocomplete, required, disabled, and label attributes.
HTML Progress Bar Generator
Generate HTML progress bar elements with value, max, label, id, class, and style attributes. Includes live preview.
HTML Quote Generator
Generate HTML <q> inline quotation elements with optional cite URL, id, class, and lang attributes. Browsers add quotation marks automatically. Live preview included.
HTML Radio Button Generator
Generate HTML radio button groups with configurable options, name, id prefix, fieldset legend, and checked/disabled states.
HTML Range Input Generator
Generate HTML range slider inputs with min, max, step, default value, label, and live output element. Includes interactive preview.
HTML Search Input Generator
Generate HTML search input elements with name, placeholder, maxlength, pattern, autocomplete, required, disabled, and label. Live preview included.
HTML Select Generator
Generate HTML <select> dropdown elements with custom options, placeholder text, multiple selection, and required/disabled attributes. Copy ready-to-use code instantly.
HTML Strikethrough Generator
Generate HTML strikethrough elements — <s>, <del>, or <strike> — with optional cite URL, datetime, id, class, and title. Live preview included.
HTML Stripper
Remove HTML tags from text, preserving line breaks and decoding HTML entities. Instant plain-text extraction from HTML.
HTML Strong Text Generator
Generate HTML <strong> elements for strong importance, seriousness, or urgency. Configure id, class, title, and lang attributes. Live preview included.
HTML Submit Input Generator
Generate HTML <input type="submit"> elements with custom value, formaction, formmethod, formtarget, disabled, id, name, and class attributes. Live preview.
HTML Subscript Generator
Generate HTML <sub> subscript elements for chemical formulas, footnote markers, and mathematical notation. Configure id, class, and title. Live preview included.
HTML Superscript Generator
Generate HTML <sup> superscript elements for exponents, ordinal indicators, footnote references, and trademark symbols. Live preview included.
HTML Table Generator
Generate HTML table code with configurable rows, columns, headers, borders, captions, and attributes. Copy ready-to-use table markup.
HTML Telephone Input Generator
Generate HTML telephone input elements with pattern validation, maxlength, autocomplete, required, readonly, disabled, and label. Live preview included.
HTML Text Input Generator
Generate HTML text input elements with placeholder, minlength, maxlength, pattern, autocomplete, spellcheck, and label attributes. Live preview included.
HTML Textarea Generator
Generate HTML textarea elements with rows, cols, placeholder, minlength, maxlength, wrap, spellcheck, and label attributes. Live preview included.
HTML Underlined Text Generator
Generate HTML <u> underline elements for unarticulated annotations, proper noun marking, and spelling error indication. Configure id, class, title, and lang. Live preview.
HTML Unescape
Convert HTML entities back to readable characters. Handles &, <, >, " and '.
HTML URL Input Generator
Generate HTML <input type="url"> elements with placeholder, pattern, autocomplete, maxlength, required, readonly, disabled, and label. Live preview included.
HTML Video Generator
Generate HTML <video> elements with multiple source formats, poster image, controls, autoplay, loop, muted, preload, width, and height. Live preview included.
HTTP Status Code Reference
Searchable reference for all HTTP status codes — with meaning, common causes, and fix recommendations.
Hyperlink Generator
Generate HTML anchor (<a>) tags with full control over href, link text, target, rel, title, class, id, style, and download attributes. Live preview included.
Integer Range Generator
Generate a sequence of integers from a start to end value with a custom step, prefix, suffix, and separator — copy or use in scripts.
IP Address Lookup
Look up geolocation, ISP, ASN, and timezone data for any IPv4 or IPv6 address — with automatic detection of your current IP.
IP to Hostname
Run a reverse DNS lookup for an IPv4 or IPv6 address and find PTR hostnames.
Java Beautifier
Beautify Java source by expanding classes, methods, loops, and statements into readable, consistently indented code.
Java Escape / Unescape
Escape or unescape text for Java string literals in your browser. Free, no signup, runs locally.
JavaScript Beautifier
Format and beautify minified or messy JavaScript code.
JavaScript Cheat Sheet
A quick JavaScript reference for variables, functions, arrays, objects, promises, DOM APIs, and common gotchas.
JavaScript Escape / Unescape
Escape or unescape text for JavaScript string literals in your browser. Free, no signup, runs locally.
JavaScript Minifier
Compress and minify JavaScript using Terser — with variable mangling, dead-code removal, and size stats.
JavaScript Obfuscator
Obfuscate JavaScript code by removing comments, minifying whitespace, and encoding string literals to make source code harder to read.
JavaScript Playground
Write and run JavaScript directly in your browser — auto-saves your code, captures console output, and supports Ctrl+Enter to run.
JavaScript Tester
Run and test JavaScript code directly in your browser — see console.log output, errors, and execution time instantly.
JavaScript Validator
Check JavaScript code for syntax errors instantly — get the error type, message, and line number without running the code.
JavaScript Viewer
View JavaScript source with syntax highlighting — keywords, strings, comments, and numbers colour-coded for easy reading.
JSON Cheat Sheet
A complete JSON reference — data types, syntax rules, nested structures, common patterns, and gotchas. Quick lookup for developers working with JSON APIs and configs.
JSON Cleaner
Clean JSON by removing null values, empty strings, empty arrays, and empty objects. Configurable per value type with a removal count stat.
JSON Decode Online
Decode a JSON-escaped string back to plain text. Unescapes quotes, backslashes, newlines, and Unicode \uXXXX sequences. Works with or without surrounding quotes.
JSON Deserialize Online
Deserialize a JSON string into a readable, formatted JSON object. Parses escaped strings, validates structure, and shows the data type.
JSON Diff
Compare two JSON objects side by side. Highlights added, removed, and unchanged lines after normalising formatting.
JSON Editor
Edit JSON in a textarea with an interactive tree view, formatting controls, key sorting, and instant validation. Copy or download the result.
JSON Encode Online
Escape a string for use as a JSON value. Handles quotes, backslashes, control characters, and optionally Unicode and forward slashes. Copy the ready-to-paste JSON string.
JSON Escape / Unescape
Escape strings for use inside JSON values or unescape JSON-encoded strings back to readable text.
JSON Fixer
Fix broken or invalid JSON automatically. Repairs trailing commas, single quotes, bare keys, Python literals, and JavaScript comments.
JSON Formatter
Format, validate, and beautify JSON instantly — with clear error messages, Tree View, Diff mode, and Schema validation.
JSON Multiline String
Escape multiline text into a valid JSON string value, or unescape a JSON string back to readable text. Handles newlines, tabs, quotes, and backslashes.
JSON Navigator
Browse JSON as a collapsible tree, select any node, and copy its JSONPath. Shows the type and size of each branch — ideal for exploring large API responses.
JSON Parser Online
Parse JSON in your browser and explore the result as an interactive collapsible tree. Reports parse errors with line and column, plus a per-type element count and depth.
JSON Path Tester
Test JSONPath expressions against your JSON.
JSON Serialize Online
Serialize a JSON object into a compact JSON string. Supports compact, pretty-printed, and double-escaped string output modes.
JSON Sorter
Sort JSON object keys alphabetically in ascending or descending order, with deep or shallow sorting and optional array sorting.
JSON Stringify Online
Stringify JSON with full control over indentation, key sorting, Unicode escaping, and JS-call wrapping. Mirrors JSON.stringify with extra options. Copy the formatted result.
JSON Syntax Highlighting
Format JSON and generate escaped syntax-highlighted HTML with light or dark themes and optional line numbers.
JSON to TypeScript Interface
Convert any JSON object into TypeScript interfaces instantly — handles nested objects, arrays, union types, optional fields, and generics.
JSON Tree Viewer
Visualize JSON data in an interactive tree structure.
JSON URL Decode
URL-decode JSON from query strings or form bodies. Optionally treats + as space (form mode) and pretty-prints the resulting JSON.
JSON URL Encode
URL-encode JSON for use in query strings or POST bodies. Supports encodeURIComponent, encodeURI, and form (x-www-form-urlencoded) modes. Optional minify-before-encode.
JSON Validator
Validate JSON syntax online. Shows valid/invalid status, error location (line and column), and structure stats including type, key count, and depth.
JSON5 Validator
Validate JSON5 syntax online — supports single-line and multi-line comments, trailing commas, single-quoted strings, unquoted keys, and hexadecimal numbers.
JSONify String
Encode any raw string into a JSON string literal — escaping double-quotes, backslashes, newlines, tabs, and all other special characters required by the JSON spec.
JSX Formatter
Format JSX and React markup by indenting nested elements, expression containers, and code blocks into readable output.
JWT Debugger
Decode, inspect, and verify JSON Web Tokens (JWT) locally.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT) without validation.
Length Converter
Convert length units between meters, kilometers, inches, feet, yards, miles, nautical miles, and metric subunits.
Lua Beautifier
Beautify Lua source by indenting blocks, functions, loops, and tables based on Lua keywords like do, then, and end.
Lua Minifier
Minify Lua source code by removing comments and collapsing whitespace — reduces file size for embedding in games, configs, or deployments.
Markdown Editor
Write Markdown with a formatting toolbar and see a live HTML preview as you type. Insert bold, italic, links, images, headings, lists, quotes, and code blocks with one click.
Markdown Formatter
Clean messy Markdown for READMEs, docs, blog drafts, and AI-generated content. Normalize headings, lists, emphasis, and tables with safe protected-zone formatting.
Markdown Table Generator
Create, format, and validate GFM Markdown tables visually — Smart Paste auto-detects CSV, spreadsheet, or existing Markdown, flags broken tables, and lets you copy or download clean output.
Markdown to HTML Converter
Convert Markdown to clean, semantic HTML with live preview — GFM tables and task lists, heading IDs, a table of contents generator, four output modes, and HTML sanitization.
Markdown Viewer
Write, preview, copy, import, export, and print Markdown in a private browser-based Markdown viewer with live GitHub Flavored Markdown preview.
Marquee Generator
Generate a scrolling marquee in modern CSS or legacy <marquee> markup. Configure direction, speed, colours, looping, and pause-on-hover with a live preview.
Mass Converter
Convert mass units between grams, kilograms, metric tons, ounces, pounds, stones, tons, and carats.
MD5 Generator
Instantly generate MD5 hashes from any text for checksums and data verification.
MDX Formatter
Format MDX files by beautifying embedded JSX components, export functions, and import statements while preserving markdown prose.
Multiple URL Opener
Paste a list of URLs, clean and de-duplicate them, then open the whole batch in new tabs.
Music Code Generator
Generate iframe embed codes for Spotify tracks, albums, and playlists; YouTube music videos; and SoundCloud tracks. Paste a share URL and copy the ready-to-use HTML.
MX Lookup
Look up mail exchange records for a domain and inspect MX priorities, hosts, and TTL values.
Nameserver Lookup
Check authoritative NS records for a domain and see which DNS provider serves the zone.
NAND Calculator
Calculate the bitwise NAND (NOT AND) of two numbers — result in decimal, binary, hex, and octal with a visual bit diagram.
NOR Calculator
Calculate the bitwise NOR (NOT OR) of two numbers — result in decimal, binary, hex, and octal with a visual bit diagram.
Number Sorter
Sort a list of numbers ascending or descending — remove duplicates, choose output format, and get min, max, sum, and average statistics.
Open Port Checker
Check whether a public TCP port is open, closed, or filtered on a hostname or IP address.
OR Calculator
Calculate the bitwise OR of two numbers — result in decimal, binary, hex, and octal with a visual bit diagram.
Perl Beautifier
Beautify Perl source code with proper indentation, consistent brace placement, and clean spacing.
PHP Beautifier
Beautify and format PHP code with proper indentation, line breaks, and consistent brace placement.
Power Converter
Convert power units between watts, kilowatts, megawatts, horsepower, BTU per hour, ft-lb/s, and calorie rates.
Pressure Converter
Convert pressure units between Pa, kPa, MPa, bar, mbar, atm, psi, Torr, mmHg, and inHg.
Punycode Converter (IDN)
Encode and decode Punycode (RFC 3492) for internationalized domain names. Converts Unicode labels to xn-- ASCII and back, one domain per line.
Python Beautifier
Normalize Python indentation — convert tabs to spaces, standardize indent size, and clean up inconsistent whitespace.
Random IP Generator
Generate safe mock IP addresses from documentation, private, loopback, and IPv6 documentation ranges.
Random JSON Generator
Generate random JSON data with realistic user records. Choose the number of records and download or copy the output.
React Formatter
Format React and JSX code with proper indentation, component tree structure, and consistent spacing.
React Native Shadow Generator
Generate cross-platform React Native shadow styles — iOS shadowColor/shadowOffset and Android elevation in one StyleSheet object.
Real-Time HTML Editor
Write HTML in a live editor and see the rendered preview update instantly. Split, editor-only, and preview-only layouts. Download the finished page or copy the code.
Regex Visualizer
Visualize regular expressions as interactive railroad diagrams — understand complex patterns with a clear SVG flowchart, live match testing, and flag explanations.
Responsive Website Tester
Preview a website inside common mobile, tablet, laptop, and desktop viewport sizes.
Reverse Hex
Reverse the byte order of a hexadecimal string (little-endian / big-endian swap). Useful for network byte order conversions and binary data analysis.
Ruby Beautifier
Beautify Ruby source code by indenting classes, methods, and blocks based on Ruby keywords like def, do, and end.
Screenshot Beautifier
Turn plain screenshots into polished PNG exports with padding, rounded corners, shadows, gradients, and browser frames.
SHA Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from text instantly in your browser.
SOAP Formatter
Format and pretty-print SOAP XML messages with proper indentation to make Envelope, Header, and Body elements readable.
Speed Converter
Convert speed units between m/s, km/h, mph, ft/s, knots, Mach, cm/s, and km/s.
SQL Code Generator
Generate SQL CREATE, INSERT, SELECT, UPDATE, and DELETE statements from a table name and column list. Supports common dialect quoting and prepared placeholders.
SQL Escape / Unescape
Escape single quotes and special characters in SQL strings. Supports ANSI standard and MySQL dialects.
SQL Formatter
Format, minify, convert, compare, and analyze SQL queries in a private browser-based SQL formatter with MySQL and PostgreSQL workflow tools.
SQL Table Generator (CREATE TABLE)
Generate CREATE TABLE statements for MySQL, PostgreSQL, SQLite, and SQL Server. Configure columns with type, length, nullability, PK, unique, auto-increment, and defaults.
Temperature Converter
Convert temperature units between Celsius, Fahrenheit, Kelvin, Rankine, and Reaumur.
Time Converter
Convert time duration units between ns, us, ms, seconds, minutes, hours, days, weeks, average months, and average years.
TOML Validator
Validate TOML 1.0 input and view the parsed structure as JSON. Reports the line number of the first syntax error with a clear message.
Turbo Search
Search one query across multiple web, code, documentation, and video search providers from one screen.
TypeScript Beautifier
Beautify and format TypeScript code with proper indentation, line breaks, and consistent spacing.
Un-Google Link
Strip Google redirect wrappers from URLs. Decode google.com/url?q=..., AMP, and utm_* tracking parameters to reveal the clean destination URL.
Unstringify JSON
Decode a JSON string literal back to its original JSON structure. Handles single and double-stringified JSON — including cases where a full JSON object has been wrapped as a string value.
User Agent Parser
Decode any User-Agent string — identify browser, engine, OS, device type, and bot classification.
UTF8 Converter
Encode text into UTF-8 byte formats or decode UTF-8 bytes back to text. Supports hex, decimal, binary, percent, and escaped views.
UTF8 Decode
Decode UTF-8 byte sequences from hex, decimal, percent-encoded, or escaped input into readable text.
Vim Cheat Sheet
A quick Vim reference for modes, movement, editing, search and replace, files, windows, and useful command combos.
Volume Converter
Convert volume units between mL, L, cubic meters, cubic feet, US cooking units, US gallons, and imperial gallons.
Webhook Tester
Receive, inspect, and debug incoming webhooks in real-time — see headers, body, query params, and method for any HTTP request sent to your unique endpoint.
Website to IP Address
Resolve a website URL or domain to its public IPv4 and IPv6 address records.
Weight Converter
Convert common weight units between grams, kilograms, ounces, pounds, stones, tons, and carats.
What is my Chinese Zodiac Sign
Find your Chinese zodiac animal, element, and yin-yang polarity from your birth date.
What is my Zodiac Sign
Enter a birth date to find the western zodiac sign, date range, element, quality, and common traits.
White Heart Symbol
Copy heart symbols, HTML codes, HTML entities, and Unicode code points. Includes the white heart 🤍, red heart ❤️, coloured hearts, and typographic heart characters.
WSDL Formatter
Format and pretty-print WSDL files with proper indentation to make types, messages, port types, bindings, and services readable.
XAML Beautifier
Beautify and format XAML markup with proper indentation to make WPF, UWP, MAUI, and Avalonia UI layouts readable.
XNOR Calculator
Calculate the bitwise XNOR (exclusive NOR) of two numbers — result in decimal, binary, hex, and octal with a visual bit diagram.
XOR Calculator
Calculate the bitwise XOR (exclusive OR) of two numbers — result in decimal, binary, hex, and octal with a visual bit diagram.
Youtube Looper
Loop a YouTube video or a selected timestamp range in an embedded repeat player.
zLib Decompress Online
Inflate zLib or deflate-compressed Base64, hex, or binary data into readable text in the browser.
Why Developer Tools Matter
Work faster with free browser-based developer tools for API debugging, JSON inspection, JWT decoding, SQL formatting, HTTP status lookup, webhook testing, cron expressions, and backend utilities. These tools are useful when you need a quick answer without opening a full IDE, terminal, or external API client.
The strongest tools here cover tasks that appear repeatedly across API work, backend debugging, and service integration: cleaning SQL queries, inspecting nested JSON, decoding JWT tokens, looking up HTTP status codes, and testing webhook payloads. They are built for real debugging sessions, not idealised tutorials.
This category connects directly into the converter category for format work, the security category for auth and hashing tasks, and the generator category for UUIDs, test data, and identifiers. When a workflow crosses those boundaries, the related-tool blocks and collection links keep the path clear.
Developer Tool Collections
Grouped workflows that connect developer tools to adjacent tasks.
API & Backend Pack
Use free API and backend developer tools for JSON formatting, JWT decoding, SQL formatting, HTTP status codes, cron expressions, Base64, URL encoding, UUIDs, and webhooks.
Security & Privacy Kit
Use free browser-based security and privacy tools for password generation, password strength checks, hash generation, JWT decoding, Base64 decoding, and hiding sensitive image data.
Developer Guides & Posts
In-depth guides and tips for getting the most out of developer tools.
How to Fix Invalid JSON: Common Errors and Examples
Fix invalid JSON fast. Learn the most common JSON syntax errors — trailing commas, missing quotes, bad nesting — with real examples and a free online validator.
How IBAN Checksum Validation Works (mod-97 Explained)
A step-by-step walkthrough of the ISO 13616 mod-97 algorithm used to validate IBAN check digits, with a worked example.
IBAN vs SWIFT/BIC: What Is the Difference?
IBAN and SWIFT/BIC are both used in international transfers but identify different things. Learn the difference and when international payments need both.
Developer FAQ
Common questions about developer tools and how to use them.
What are the best free developer tools online?
JSON Tree Viewer, JWT Decoder, SQL Formatter, HTTP Status Codes, Webhook Tester, and JSON to TypeScript cover the most common API and backend debugging tasks. These are the tools that come up repeatedly in real development sessions.
Which developer tools are useful for API debugging?
For API debugging, start with JSON Tree Viewer, HTTP Status Codes, Webhook Tester, and JWT Decoder. These tools help you inspect payloads, understand response codes, test integration endpoints, and decode auth tokens without setting up a local environment.
Can I decode JWT tokens online safely?
Yes. JWT Decoder inspects token headers and payloads in your browser. Decoding only reveals the contents — it does not verify the signature. Do not paste live production tokens, admin tokens, customer secrets, or private keys into any online tool.
What is the difference between JSON Formatter and JSON Tree Viewer?
JSON Formatter makes JSON readable by adding indentation and structure. JSON Tree Viewer lets you explore nested JSON visually by expanding and collapsing objects and arrays interactively — useful when the payload is deeply nested or very large.
Can I format SQL queries online?
Yes. SQL Formatter beautifies messy or minified SQL queries into readable, indented output. It is useful when inspecting copied queries, reviewing joins and nested conditions, or preparing SQL for documentation or code review.
Which tools are useful for backend developers?
Backend developers most often reach for SQL Formatter, JWT Decoder, HTTP Status Codes, Webhook Tester, Cron Expression Generator, and Epoch Converter. These cover the common tasks that come up during API integration, service debugging, and scheduled job work.
Can I generate test data for APIs?
Yes. UUID Generator creates unique identifiers for test records. Random Data Generator and Mock API Response tools in the Generator category produce structured test payloads for frontend mocking, API testing, and development seed data.