Free Online Tools for Developers

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Essential browser-based utilities for web developers, backend engineers, and DevOps professionals. Format data, test patterns, decode tokens, and generate identifiers — all without leaving your browser.

Whether you are debugging an API response, validating a regex pattern, or generating UUIDs for a database migration, these tools are built for the workflows developers encounter daily. Every tool runs entirely in your browser — no data is sent to any server, so you can safely work with API keys, tokens, and production data.

Bookmark this page as your developer toolkit. All tools are free, require no signup, and work offline once loaded.

JSON Formatter & Validator

Paste JSON to auto-format, prettify, and validate with error messages.

Regex Tester

Test regex patterns with real-time match highlighting and group display.

JWT Decoder

Decode JWT tokens to view header and payload as formatted JSON.

Base64 Encode/Decode

Encode text to Base64 or decode Base64 back to text.

URL Encoder/Decoder

Encode or decode URL components with swap and output-to-input workflow.

HTML Entity Encoder/Decoder

Convert special characters to HTML entities and back.

Diff Checker

Compare two texts side by side with highlighted differences.

Markdown Preview

Write Markdown on the left, see rendered HTML preview on the right.

YAML ↔ JSON Converter

Convert YAML to JSON and JSON to YAML instantly with error highlighting and download.

JSON to CSV Converter

Convert a JSON array of objects to CSV format with instant preview and download.

CSV to JSON Converter

Convert CSV data to JSON format instantly. Supports quoted fields and multi-line values.

Timestamp Converter

Convert Unix timestamps to dates and vice versa with live current timestamp.

Number Base Converter

Convert numbers between Binary, Octal, Decimal, and Hexadecimal.

Cron Expression Parser

Parse and explain cron expressions in plain English with next scheduled run times.

UUID Generator

Generate v4 UUIDs with bulk generation, accessible item copy, and robust input validation.

Password Generator

Generate strong passwords with configurable length and character types.

Hash Generator

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

CSS Gradient Generator

Generate linear, radial, and conic CSS gradients with live preview and one-click copy.

Color Contrast Checker

Check WCAG accessibility compliance for text and background color combinations.

Text to Slug Converter

Convert any text to a URL-friendly slug with live preview.

Text Case Converter

Convert text to UPPERCASE, lowercase, Title Case, camelCase, snake_case, and more.

Schema Markup Generator

Generate JSON-LD schema markup for Organization, FAQPage, and Article.

robots.txt Generator

Build and download a robots.txt file with presets for Allow All, Block All, AI bots, and WordPress.

What Is My IP + Device Info

View detected IP candidates, user agent, platform, and device/network information.

Internet Speed Test

Measure download, upload, and ping using browser-based network tests.

Electronic Signature Maker

Draw or type a signature and embed it into a PDF document — all in your browser.

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