Free online tools
for developers
Format and validate JSON, decode JWTs, encode Base64, test regular expressions, format SQL and convert between data formats — free, with no sign-up, and processed in your browser.
Popular developer tools
JSON Formatter
Format, validate and minify JSON with syntax highlighting and error detection.
JWT Decoder
Decode and inspect JWT tokens — header, payload, signature at a glance.
Base64 Encoder
Encode and decode Base64 strings instantly — supports text and URL-safe mode.
Regex Tester
Test and debug regular expressions with live match highlighting and group capture.
SQL Formatter
Beautify or minify SQL queries with proper indentation, keyword casing and structure.
Private Notes
Send a self-destructing, end-to-end encrypted note. The link works once, then the note is deleted.
JSON Tools
Free online JSON tools: format and validate JSON, compare two JSON documents, explain JSON structure, escape JSON strings and generate mock JSON data.
JSON Formatter
Format, validate and minify JSON with syntax highlighting and error detection.
JSON Compare
Compare two JSON objects side-by-side and detect added keys, removed keys, and changed values.
JSON Explainer
Paste any JSON and get a plain-English breakdown of every key, type, and nested structure — no AI API needed.
Fake JSON Generator
Generate realistic fake JSON datasets with custom fields — names, emails, addresses, and more.
Data Converters
Convert between JSON, CSV, YAML and XML online. Two-way converters for API payloads, spreadsheets and configuration files, running in your browser.
JSON to CSV Converter
Convert a JSON array to CSV with a header row, or turn CSV back into JSON.
JSON to YAML Converter
Convert JSON to YAML for configuration files, or YAML back to JSON.
JSON to XML Converter
Convert JSON objects to XML elements, or parse XML back into JSON.
YAML to XML Converter
Convert YAML documents to XML, or XML back to YAML.
CSV to YAML Converter
Convert CSV rows to a YAML list, or YAML back to CSV.
XML to CSV Converter
Flatten repeated XML elements into CSV rows, or build XML from CSV.
Encoding & Escaping
Encode and decode Base64 and URLs, and escape or unescape strings for HTML, XML, JSON, JavaScript, Java, C#, CSV and SQL. Free online tools.
Base64 Encoder
Encode and decode Base64 strings instantly — supports text and URL-safe mode.
URL Encoder/Decoder
Encode text to URL format and decode URL-encoded strings with Unicode support.
HTML Escape/Unescape
Escape and unescape HTML strings — convert special characters to/from entities safely.
XML Escape/Unescape
Escape and unescape XML strings — properly encode special characters for XML documents.
JSON Escape/Unescape
Escape and unescape JSON strings — ensure valid JSON formatting with proper character escaping.
JavaScript Escape/Unescape
Escape and unescape JavaScript strings — convert special characters to escape sequences.
Java Escape/Unescape
Escape and unescape Java strings — generate Java-safe escaped strings with proper Unicode support.
.NET Escape/Unescape
Escape and unescape .NET (C#) strings — generate C#-safe escaped strings with Unicode support.
CSV Escape/Unescape
Escape and unescape CSV fields — handle commas, quotes, and multiline values properly.
SQL Escape/Unescape
Escape and unescape SQL string literals: double single quotes and backslash-escape special characters (MySQL style).
Security & Tokens
Decode JWTs, generate MD5 and SHA hashes, create strong random passwords and send self-destructing encrypted notes. Free, browser-based security tools.
JWT Decoder
Decode and inspect JWT tokens — header, payload, signature at a glance.
JWT Parser
Decode and inspect JWT tokens — view header, payload, and signature structure.
Hash Generator
Generate MD5, SHA-1, SHA-256 and SHA-512 hashes instantly. Real-time, fully client-side.
Password Generator
Generate secure passwords with custom length, character options, and strength indicator.
Private Notes
Send a self-destructing, end-to-end encrypted note. The link works once, then the note is deleted.
Code Formatters
Beautify and minify HTML, CSS and SQL, and write Markdown with a live preview. Free online code formatters for cleaning up and reviewing code.
HTML Formatter
Beautify messy HTML markup with syntax highlighting and a live sandboxed preview.
CSS Formatter
Beautify or minify CSS stylesheets with size savings stats and syntax highlighting.
SQL Formatter
Beautify or minify SQL queries with proper indentation, keyword casing and structure.
Markdown Editor
Write and preview markdown with GitHub-flavored markdown support. Live preview as you type.
Text & Regex Tools
Test and explain regular expressions, compare two texts or files line by line, and generate Lorem Ipsum placeholder text. Free online text tools.
Regex Tester
Test and debug regular expressions with live match highlighting and group capture.
Regex Explainer
Paste any regular expression and get a plain-English explanation of every token — anchors, groups, quantifiers and more.
Diff Checker
Compare two text inputs and visualize differences with color-coded highlighting.
Text Compare
Compare two text inputs line-by-line with diff highlighting, case and whitespace toggles.
Lorem Ipsum Generator
Generate placeholder text — paragraphs, sentences, or words for design mockups and prototypes.
Generators & Utilities
Generate UUIDs and QR codes, convert Unix timestamps, build cron expressions and convert HEX, RGB and HSL colors. Free online developer utilities.
UUID Generator
Generate random unique UUIDs (v4) in multiple formats — perfect for IDs and tokens.
Timestamp Converter
Convert Unix timestamps to readable dates and back. Supports seconds, milliseconds, and timezones.
Cron Generator
Build cron expressions visually, get a human-readable explanation and preview upcoming runs.
QR Code Generator
Generate scannable QR codes from text or URLs instantly. Download as PNG image.
Color Picker
Convert between HEX, RGB, and HSL color formats instantly. Perfect for web design and CSS.
API TesterSoon
Make HTTP requests, inspect headers and responses. (Backend coming soon)
Why FormatCraft?
Your input stays in your browser
The tools process what you paste locally, in JavaScript — it is not uploaded to our servers. The one exception is Private Notes, which stores an end-to-end encrypted copy of a note that we cannot read.
No account, no install
Every tool is free and works straight away in any modern browser. There is nothing to sign up for and nothing to download.
Built for everyday developer work
Focused tools for the jobs that come up constantly: reading API responses, debugging tokens, fixing escaping, formatting queries and comparing files.
Frequently asked questions
Are FormatCraft tools free to use?
Yes. All tools are free, with no usage limits and no account required.
Is the data I paste sent to a server?
No — the tools run in your browser and your input is not uploaded. Private Notes is the exception: it uploads an end-to-end encrypted note so it can be shared, and the decryption key stays in the link. The site uses Google Analytics to measure aggregate traffic; see the Privacy Policy for details.
Where should I start?
For API and debugging work, the JSON Formatter, JWT Decoder, Base64 Encoder and Regex Tester cover the most common tasks. Browse the categories above to find the rest.
What do I need to run the tools?
A current version of Chrome, Firefox, Safari or Edge with JavaScript enabled. The tools work on desktop and mobile.