Free Online Converters
Convert between JSON, CSV, Base64, hex, colors, number bases, and more. All tools run entirely in your browser.
Converter Tools
JSON to CSV Converter
Convert JSON arrays to CSV and CSV to JSON online. Supports custom delimiters, proper escaping, nested objects, and file download.
JSON Formatter / Validator
Format, minify, and validate JSON data online. Pretty-print with configurable indentation and see detailed error positions for invalid JSON.
Base64 Encoder / Decoder
Encode and decode Base64 strings online. Supports text and hex input with URL-safe Base64 option for Ethereum development.
Hex / Decimal Converter
Convert between hexadecimal and decimal numbers. Useful for Ethereum block numbers, values, and calldata.
Color Picker / Converter
Pick colors and convert between HEX, RGB, and HSL formats. Check WCAG contrast ratios, generate shades, and get CSS values.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal online. Supports arbitrarily large numbers with BigInt.
Image to Base64 Converter
Convert images to Base64 encoded strings online. Drag and drop PNG, JPG, GIF, SVG, or WebP files to get Data URIs for HTML, CSS, and JSON.
HTML Encoder / Decoder
Encode and decode HTML entities online. Convert special characters to HTML entities for safe display in web pages.
URL Encoder / Decoder
Encode and decode URL components online. Compare encodeURIComponent vs encodeURI with a common URL encodings reference table.
About Each Converter
JSON to CSV Converter
Convert JSON arrays to CSV spreadsheet format and vice versa. Handles nested objects, custom delimiters, proper CSV escaping, and file downloads. Works with API responses, database exports, and any structured JSON data.
JSON Formatter / Validator
Format, minify, and validate JSON data. Pretty-print with configurable indentation or compress to a single line. Get detailed error messages pointing to the exact line and character of syntax errors.
Base64 Encoder / Decoder
Encode text or hex data to Base64 and decode Base64 back to the original format. Supports standard Base64 and URL-safe Base64 variants used in JWTs, data URIs, and API authentication.
Hex / Decimal Converter
Convert between hexadecimal and decimal numbers instantly. Handles arbitrarily large numbers using BigInt. Essential for working with Ethereum block numbers, gas values, and raw transaction data.
Color Picker / Converter
Pick colors visually and convert between HEX, RGB, and HSL formats. Check WCAG contrast ratios for accessibility compliance, generate shade variations, and copy CSS-ready color values.
Number Base Converter
Convert numbers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Supports arbitrarily large numbers with BigInt for working with cryptographic values and large integers.
Image to Base64 Converter
Convert images to Base64-encoded data URI strings. Drag and drop PNG, JPG, GIF, SVG, or WebP files and get inline-ready strings for HTML, CSS, and JSON. Shows file size and encoded size.
HTML Encoder / Decoder
Encode special characters to HTML entities and decode entities back to characters. Prevents XSS vulnerabilities when displaying user-generated content in web pages. Handles named entities, decimal, and hexadecimal references.
URL Encoder / Decoder
Encode and decode URL components using percent-encoding. Compare the behavior of encodeURIComponent and encodeURI. Includes a reference table of common URL-encoded characters.
Frequently Asked Questions
How do I convert JSON to CSV online?
Paste your JSON array into the JSON to CSV tool. It automatically detects the structure, flattens nested objects, and generates a CSV file with proper escaping. You can customize the delimiter (comma, tab, semicolon) and download the result as a .csv file.
What is Base64 encoding used for?
Base64 encoding converts binary data into ASCII text, making it safe to transmit through text-based protocols like email (MIME), URLs, and JSON. Common uses include embedding images in HTML/CSS (data URIs), encoding API authentication tokens, and transmitting binary data in REST APIs.
How do I convert between hex and decimal?
Use the Hex / Decimal Converter to instantly convert numbers between hexadecimal (base 16) and decimal (base 10). This is essential for Ethereum development where block numbers, gas values, and addresses are often displayed in hex format.
What color formats does the Color Picker support?
The Color Picker converts between HEX (#FF5733), RGB (rgb(255, 87, 51)), and HSL (hsl(11, 100%, 60%)) color formats. It also checks WCAG contrast ratios for accessibility, generates shade variations, and provides ready-to-use CSS values.
How do I convert an image to Base64?
Drag and drop an image file (PNG, JPG, GIF, SVG, or WebP) into the Image to Base64 tool. It generates a Base64-encoded data URI string that you can embed directly in HTML img tags, CSS background properties, or JSON payloads without needing a separate image file.
What is the difference between URL encoding and HTML encoding?
URL encoding (percent-encoding) converts special characters into %XX format for use in URLs and query strings. HTML encoding converts characters like <, >, &, and quotes into HTML entities (<, >, &) for safe display in web pages. They serve different purposes but both prevent injection attacks.