117+ developer tools that just work.
A focused collection of fast, privacy-friendly utilities for everyday development — from JSON to QR codes.
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Formatters
Compare Anything
Side-by-side diff for JSON, XML, contracts, specs, job offers — with decision matrix.
JSON Formatter
Format, beautify, minify and validate JSON instantly in your browser.
XML Formatter
Pretty-print, minify and validate XML documents online.
YAML Formatter
Validate and re-emit YAML in a clean normalized form.
SQL Formatter
Format SQL queries with proper indentation and keyword casing.
HTML Formatter
Pretty-print or minify HTML markup.
CSS Formatter
Beautify or minify CSS stylesheets.
JS Minifier
Strip comments and whitespace from JavaScript safely.
JSON Diff
Compare two JSON objects and see added, removed and changed keys.
JSON Sort
Sort object keys alphabetically at every depth.
JSON Path
Query JSON with dot/bracket paths and JSONPath expressions.
SVG Minifier
Minify SVG markup by stripping comments, metadata and whitespace.
CSV Diff
Compare two CSV files row-by-row to find changes.
Converters
YAML ↔ JSON
Convert YAML to JSON and JSON to YAML.
CSV ↔ JSON
Convert CSV spreadsheets to JSON arrays and back.
JSON ↔ XML
Convert between JSON and XML with one click.
JSON → TS
Generate TypeScript interfaces from any JSON sample.
Timestamp ↔ Date
Convert between Unix timestamps and human dates.
Number Base
Convert numbers between binary, octal, decimal and hex.
CIDR Calculator
Calculate network range, mask, hosts and broadcast for any CIDR.
CSV → Markdown
Convert CSV data to GitHub-flavored Markdown tables.
SVG → CSS
Convert SVG to a data-URI usable as a CSS background.
curl → fetch
Convert curl commands into JavaScript fetch() calls.
HTML → JSX
Convert HTML markup into valid React JSX.
JSON → Schema
Generate a JSON Schema (draft-07) from any JSON sample.
Timestamp Batch
Convert a list of Unix timestamps to dates (or vice versa).
Image Resize
Resize PNG, JPG, WebP images in your browser — keep or break aspect ratio.
Image Compress
Compress JPEG and WebP images by adjusting quality.
Image Convert
Convert between PNG, JPEG and WebP image formats.
Encoders
Base64 ↔ File
Encode or decode Base64 text and convert files to/from Base64.
URL Encoder
Percent-encode or decode URLs and query strings safely.
HTML Entities
Escape HTML special characters or decode named/numeric entities.
String Escape
Escape strings for JSON, JavaScript, SQL and shell.
Base32
Encode and decode Base32 strings (RFC 4648).
Image → Base64
Convert any image (PNG, JPG, SVG, WebP, GIF) to a base64 data URI.
Base64 → Image
Decode a base64 string or data URI back into a downloadable image.
Generators
UUID Generator
Generate cryptographically random UUIDs (v4).
Password Generator
Generate strong random passwords with customizable rules.
Lorem Ipsum
Generate placeholder text in paragraphs, sentences or words.
QR Generator
Generate downloadable QR codes for any URL or text.
Slug Generator
Convert any text into a clean URL-safe slug.
.gitignore Generator
Combine .gitignore templates for popular languages and IDEs.
Placeholder Image
Generate placeholder image URLs for mockups and prototypes.
Passphrase
Generate strong memorable passphrases from a random word list.
vCard Generator
Build a vCard 3.0 contact card and download as .vcf.
OG Meta Tags
Generate Open Graph and Twitter Card meta tags with live preview.
robots.txt
Build a robots.txt file with rules for search engine crawlers.
Cron Builder
Build cron expressions visually and see the next run times.
Text
Markdown Preview
Live preview of GitHub-flavored Markdown.
Markdown → HTML
Convert Markdown to clean HTML you can copy.
Text Diff
Compare two blocks of text line-by-line.
Case Converter
Transform text between camelCase, snake_case, kebab-case and more.
Word Counter
Count words, characters, sentences and reading time.
Regex Tester
Test JavaScript regular expressions with live highlighting.
Markdown Table
Build Markdown tables visually — add rows and columns, then copy.
Sort Lines
Sort lines alphabetically, numerically, by length, ascending or descending.
Dedupe Lines
Remove duplicate lines from any text block.
Reverse Text
Reverse a string character-by-character or reverse line order.
Find & Replace
Find and replace text with optional regex, case and word options.
Whitespace Cleaner
Trim, normalize or strip whitespace from text.
Text Repeater
Repeat any string a chosen number of times with separators.
Unicode Inspector
Inspect every character: codepoint, name, hex, UTF-8 bytes.
ASCII Table
Searchable ASCII table with hex, decimal, octal and HTML codes.
Markdown TOC
Generate a Table of Contents from Markdown headings.
Email Validator
Validate email syntax for many addresses at once.
String Similarity
Compare two strings: Levenshtein distance, similarity %.
Readability
Compute Flesch Reading Ease and grade-level scores for any text.
Keyword Density
Count word frequency and density for SEO content analysis.
CSS
Gradient Generator
Build linear and radial CSS gradients visually.
Box Shadow
Visually craft CSS box-shadow rules with live preview.
Border Radius
Generate CSS border-radius shapes with corner control.
Flexbox Playground
Visually test flex container and item properties.
CSS Grid
Generate CSS grid-template-columns/rows visually.
CSS Units
Convert between px, em, rem and percent based on root size.
Color Palette
Generate complementary, analogous and triadic palettes from any color.
WCAG Contrast
Check WCAG AA / AAA contrast ratios between two colors.
CSS clamp()
Generate fluid responsive clamp() values for typography and spacing.
Box Model
Interactively visualize margin, border, padding and content.
Math
Random Number
Generate random integers or decimals in any range.
Dice Roller
Roll dice using standard RPG notation like 2d6+3 or 1d20.
Roman Numerals
Convert between Roman numerals and Arabic numbers.
Percentage Calc
Calculate percentages, increases, decreases and ratios.
Unit Converter
Convert length, weight, temperature, volume and more.
EMI Calculator
Compute monthly payments, total interest and amortization.
BMI
Compute Body Mass Index in metric or imperial units.
Luhn Checker
Validate credit card numbers using the Luhn checksum.
Aspect Ratio
Calculate width or height keeping the aspect ratio.
Date
Age Calculator
Calculate exact age in years, months, days and total seconds.
Date Diff
Calculate the difference between two dates.
Timezone Converter
Convert times across world time zones.
Pomodoro Timer
Classic 25/5 Pomodoro technique with sound and notification.
Stopwatch
Millisecond-precision stopwatch with lap times.
Countdown Timer
Set a countdown to any duration or target date with sound alert.
Web
HTTP Status
Search 1xx–5xx HTTP status codes with descriptions.
User-Agent
Parse browser, OS and device from any User-Agent string.
Cron Explainer
Translate cron expressions into plain English.
Color Converter
Convert between HEX, RGB and HSL formats with live preview.
Semver Compare
Compare semantic versions and check ranges.
MIME Lookup
Search MIME types by file extension or vice versa.
UUID Inspector
Validate UUIDs and decode v1/v7 timestamps.
URL Parser
Parse a URL into protocol, host, path, query and hash.
IPv4 ↔ IPv6
Convert IPv4 addresses to IPv6-mapped form and back.
Webcam Snapshot
Capture a still photo from your webcam and download it as PNG.
Text to Speech
Read any text aloud using built-in browser voices.
Notepad
Distraction-free notepad with localStorage auto-save and word count.
Cipher
Crypto
JWT Decoder
Decode and inspect JSON Web Tokens — header, payload and signature.
Hash Generator
Generate cryptographic hashes using the Web Crypto API.
HMAC Generator
Generate keyed-hash message authentication codes (HMAC).
JWT Builder
Sign JSON Web Tokens locally with HS256, HS384 or HS512.
Password Strength
Estimate password entropy and crack time live.
.htpasswd
Generate Apache .htpasswd lines (SHA-1) in your browser.
File Hash
Compute SHA-1, SHA-256, SHA-384 and SHA-512 of any file, locally.
Text Encrypt
Encrypt and decrypt text with a password using AES-GCM.
Every tool runs locally. We never see, store or transmit your input.
Optimized static files served globally — first byte in milliseconds.
Supported by unobtrusive ads. No paywalls, no account required.
Why Choose ProgrammerKit?
In modern software engineering, having the right utility at the exact moment you need it can save hours of frustration. That's why we built ProgrammerKit—a comprehensive, ever-expanding suite of free online developer tools. Whether you are debugging a complex API response, securing a server configuration, or simply trying to convert an image format, our platform provides instant answers directly in your browser.
100% Client-Side Processing for Ultimate Privacy
Security is paramount. Unlike many other online formatter tools that send your sensitive JSON, YAML, or database strings to remote servers to be processed, ProgrammerKit leverages modern Web APIs to handle everything locally. When you use our JWT Decoder, SQL Formatter, or Hash Generator, your data never leaves your device. This guarantees that API keys, proprietary algorithms, and customer data remain strictly under your control.
Optimized for Speed and Developer Productivity
As developers ourselves, we hate slow-loading websites cluttered with intrusive scripts. ProgrammerKit is engineered as a highly optimized static platform. The utilities load in mere milliseconds, ensuring you can quickly format CSS, compress images, or calculate IP subnets without losing your flow state. Our fast search capability lets you find tools like "Base64 Encoder" or "CSV to Markdown Converter" in an instant.