Developer Utilities

Free Online Developer & Utility Tools

Format JSON, encode Base64, generate UUIDs, convert timestamps, calculate dates, convert units, check browser info, and more — free browser-based utilities with no signup required.

No uploadsInstant resultsPrivate by design

Developer Tools

44 tools

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JSON Formatter

Prettify and format JSON with configurable indent — minify option included.

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JSON Validator

Validate JSON syntax instantly with helpful error messages.

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Base64 Encode

Encode text or files to Base64 — supports UTF-8 and binary.

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Base64 Decode

Decode Base64 strings back to plain text or download as a file.

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URL Encode

Percent-encode text for safe use in URLs and query strings.

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URL Decode

Decode percent-encoded URLs and query strings to readable text.

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UUID Generator

Generate cryptographically random UUID v4 identifiers in bulk.

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Password Generator

Generate strong, random passwords with custom length and character sets.

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Hash Generator

Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from text or any file.

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Color Converter

Convert colors between HEX, RGB, and HSL formats with live preview.

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XML Formatter

Prettify or minify XML documents with configurable indentation.

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Markdown to HTML

Convert Markdown text to HTML with live preview and one-click download.

Popular

QR Code Generator

Generate QR codes for URLs, text, email, phone, SMS, and WiFi — custom colors, sizes, EC levels.

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HTML Formatter

Prettify or minify HTML with configurable indentation — browser-based, no uploads.

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CSS Formatter

Format, prettify, or minify CSS with configurable indentation — instant, browser-based.

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JSON to XML

Convert JSON objects and arrays to formatted XML — handles nested objects, arrays, and null values.

JSONXML

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Word Counter

Count words, characters, sentences, paragraphs, and reading time instantly.

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Character Counter

Count characters, spaces, lines, and paragraphs in real time.

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Text Case Converter

Convert text to uppercase, lowercase, title case, camelCase, snake_case, and more.

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Remove Duplicate Lines

Remove repeated lines from any text — lists, keywords, URLs, or IDs. Keeps first occurrence.

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Sort Lines

Alphabetize text lines A to Z or Z to A — browser-based, no upload.

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Remove Empty Lines

Delete blank or whitespace-only lines from text — instant, browser-based, no upload.

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Line Counter

Count total lines, non-empty lines, empty lines, words, and characters — live, browser-based.

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Text Reverser

Reverse text characters, word order, or line order online — private, browser-based, no upload.

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Slug Generator

Generate SEO-friendly URL slugs from titles — configurable separator and casing, no upload.

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JSON Minifier

Validate and minify JSON instantly — strips whitespace for the smallest valid JSON string.

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QR Code Reader

Decode QR codes from uploaded images or your device camera — instant, browser-based, no uploads.

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JWT Decoder

Decode JWT header and payload instantly. Inspect claims, expiry, and algorithm — browser-only.

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YAML to JSON

Convert YAML to clean, formatted JSON — handles nested objects, arrays, and scalars.

YAMLJSON

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JSON to YAML

Convert any valid JSON to clean, indented YAML — browser-based, no uploads.

JSONYAML

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YAML Formatter

Prettify and format YAML with consistent 2-space indentation — validates as it formats.

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JavaScript Formatter

Beautify and format messy or minified JavaScript code online — browser-based, private, no upload.

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JavaScript Minifier

Remove comments and collapse whitespace from JavaScript code — browser-only, instant.

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HTML Minifier

Remove HTML comments and inter-tag whitespace for smaller HTML files — browser-only.

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CSS Minifier

Strip CSS comments and whitespace for the smallest possible stylesheet — browser-only.

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Regex Tester

Test JavaScript regular expressions live in your browser — matches, capture groups, flags. No upload.

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Text Diff Checker

Compare two blocks of text and highlight added, removed, and unchanged lines — browser-only.

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JSON Diff Checker

Semantically compare two JSON objects — find added, removed, and changed keys. Ignores whitespace.

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Barcode Generator

Generate Code 128, EAN-13, EAN-8, UPC-A, Code 39, and ITF-14 barcodes — browser-based, download as SVG or PNG.

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Barcode Reader

Scan barcodes from images in your browser — Code 128, EAN-13, UPC-A, QR codes, and more. No upload.

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ZIP Creator

Compress multiple files into a ZIP archive — browser-based, no uploads, private.

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ZIP Extractor

Open and extract ZIP files in your browser — view contents, download individual files, no upload.

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Image to Base64

Convert PNG, JPG, WebP, GIF, or SVG to a Base64 data URL — browser-based, no uploads.

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Base64 to Image

Paste a Base64 data URL or raw Base64 string to preview and download the decoded image.

Date & Time

10 tools

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Timestamp Converter

Convert Unix timestamps to human-readable dates and back — with live current time.

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Date Difference Calculator

Calculate the exact number of days, weeks, and months between any two dates.

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Age Calculator

Calculate exact age in years, months, and days — plus total days lived and next birthday countdown.

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Add / Subtract Days

Add or subtract any number of days from a date to find the resulting date and day of week.

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Business Days Calculator

Count weekdays (Mon–Fri) between two dates. Weekdays only — no holiday exclusion.

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Time Duration Calculator

Calculate the elapsed time between two datetimes — days, hours, minutes, and seconds.

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Time Zone Converter

Convert any time between IANA time zones. DST handled automatically by the browser.

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Week Number Calculator

Find the ISO 8601 week number for any date — plus ISO week-year and day of week.

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Day of Year Calculator

Find which day of the year a date falls on — plus days remaining and leap year status.

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12 / 24-Hour Time Converter

Instantly convert between 12-hour AM/PM and 24-hour (military) time formats.

Calculators & Converters

6 tools

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File Size Converter

Convert between bytes, KB, MB, GB, TB, and PB — decimal (SI) and binary (IEC) units.

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DPI Calculator

Calculate DPI from pixel dimensions and print size, or find the print size at any DPI.

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Image Print Size Calculator

Enter pixel dimensions and DPI to calculate the maximum print size in inches, cm, and mm.

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Aspect Ratio Calculator

Simplify any W×H to its lowest-terms ratio and scale images proportionally.

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Percentage Calculator

Five percentage modes: X% of Y, X is what % of Y, % change, add X%, subtract X%.

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Unit Converter

Convert length, weight, temperature, area, volume, and speed units instantly.

Web & Browser

4 tools

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Browser Information Checker

See your browser name, OS, screen, viewport, language, timezone, and device details — read locally.

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User Agent Parser

Paste any user-agent string to detect browser, version, OS, device type, and rendering engine.

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What Is My IP Address?

Instantly see your public IPv4 or IPv6 address. Fetched via ipify — no signup, no files uploaded.

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IP Lookup

Look up any IPv4 or IPv6 address for approximate location, ISP, ASN, and timezone.

100% Browser-Based

No Server, No Tracking

Every tool on ConvertForge runs entirely in your browser. JSON data, passwords, encoded strings — none of it is ever sent to a server. Safe for sensitive data.

JSON Formatter UUID Generator Password Generator

Free online developer utilities

ConvertForge's developer tools are a growing set of lightweight, browser-based utilities for everyday development tasks. Each tool is designed to be fast, private, and free to use without an account.

Tools include a JSON formatter, JSON validator, and JSON minifier for debugging and compressing API responses; a Base64 encoder and decoder for binary data and data URIs; a URL encoder and decoder for query strings; a UUID v4 generator; a hash generator (MD5, SHA-1, SHA-256); a timestamp converter; a QR code generator and QR code reader; a word counter; a text case converter; and a password generator.

Privacy and security

All processing happens in your browser. Your JSON data, passwords, and encoded strings are never sent to any server. The UUID and password generators use the browser's native crypto API for cryptographically secure randomness.

Frequently Asked Questions

Are these tools free forever?

Yes — completely free with no account, no subscription, and no usage limits.

Do any of these tools send data to a server?

No. Every tool processes data locally in your browser. Nothing is transmitted.

What browsers are supported?

Any modern browser on Mac, Windows, Linux, iOS, or Android — Chrome, Firefox, Safari, and Edge all work.

Will more developer tools be added?

Yes — we are actively expanding the developer tools section. Upcoming tools include hash generators, regex testers, and more.

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