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Developer Tools

Free Developer Tools

Everyday utilities for programmers: format and validate data, encode and decode strings, test regular expressions, generate hashes and UUIDs, and convert between formats. Every tool runs locally in your browser, so code, tokens and secrets you paste are never uploaded.

JSON Formatter & Validator

Beautify, minify and validate JSON with error locations.

JSON to CSV Converter

Convert JSON arrays to CSV, flattening nested objects.

CSV to JSON Converter

Convert CSV or TSV data to a JSON array.

JSON ⇄ YAML Converter

Convert JSON to YAML and YAML to JSON.

XML Formatter

Beautify, minify and validate XML documents.

Base64 Encode & Decode

Encode text to Base64 or decode Base64 to text (UTF-8).

URL Encode & Decode

Percent-encode or decode URLs and query strings.

HTML Entity Encoder & Decoder

Escape and unescape HTML entities like &lt; and &#169;.

JWT Decoder

Decode JSON Web Tokens: header, payload and expiry.

Hash Generator

MD5, SHA-1, SHA-256, SHA-384 & SHA-512 for text or files.

UUID Generator

Generate random v4 or time-ordered v7 UUIDs in bulk.

JSON String Escape & Unescape

Escape text for JSON/JS strings or unescape it back.

Regex Tester

Test regular expressions with live match highlighting.

Diff Checker

Compare two texts and highlight the differences.

Unix Timestamp Converter

Convert Unix epoch time to dates and back.

Number Base Converter

Convert between binary, octal, decimal and hex.

HTML Formatter

Beautify or minify HTML code with clean indentation.

CSS Formatter & Minifier

Beautify or minify CSS and see the size savings.

JavaScript Minifier

Minify or beautify JavaScript with Terser.

SQL Formatter

Format SQL queries for MySQL, PostgreSQL and more.

Markdown to HTML

Convert Markdown to HTML with live preview.

Cron Expression Parser

Explain cron schedules and list the next run times.

Chmod Calculator

Convert Linux file permissions between 755 and rwx.

URL Parser

Break a URL into parts and edit its query parameters.

All developer tools at a glance

Tool	What it does
JSON Formatter & Validator	Format, beautify, minify and validate JSON online for free. Pinpoints syntax errors by line and column, sorts keys, and formats instantaneously in your browser.
JSON to CSV Converter	Convert a JSON array of objects into CSV for Excel or Google Sheets. Nested objects are flattened into dot-notation columns. Choose the delimiter and download.
CSV to JSON Converter	Convert CSV or TSV to JSON online. Handles quoted fields, commas and line breaks inside quotes, auto-detects the delimiter and can convert numbers and booleans.
JSON ⇄ YAML Converter	Convert JSON to YAML and YAML to JSON instantly. Great for Kubernetes manifests, Docker Compose, GitHub Actions and OpenAPI files. Clear error messages.
XML Formatter	Format and beautify XML with proper indentation, minify it to one line, and validate that it is well-formed. Works with SOAP, RSS, sitemaps and SVG files.
Base64 Encode & Decode	Encode text to Base64 and decode Base64 back to text online. Full UTF-8 and emoji support, plus URL-safe Base64 (base64url) used in JWTs and web URLs.
URL Encode & Decode	URL encode and decode text online. Percent-encode query parameters with encodeURIComponent or full URLs with encodeURI, and decode %20-style strings safely.
HTML Entity Encoder & Decoder	Encode special characters to HTML entities and decode entities back to text. Supports named (&copy;), decimal and hex numeric entities. Prevents broken markup.
JWT Decoder	Decode a JSON Web Token to view its header and payload claims, with human-readable exp, iat and nbf dates and an expiry check. Runs locally, nothing is uploaded.
Hash Generator	Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or files online. Verify file checksums against an expected hash. Files never leave your device.
UUID Generator	Generate random UUID v4 or time-ordered UUID v7 identifiers, one or up to 1,000 at a time. Uppercase and no-hyphen options, cryptographically secure randomness.
JSON String Escape & Unescape	Escape text for use inside JSON or JavaScript string literals, or unescape \n, \t, \" and \uXXXX sequences back to plain text. Handles quotes, newlines and Unicode.
Regex Tester	Test JavaScript regular expressions online with live match highlighting, capture and named groups, flags and a replace preview. Includes common regex presets.
Diff Checker	Compare two texts or code files online and highlight every difference by line, word or character. Ignore whitespace or case and see added and removed counts.
Unix Timestamp Converter	Convert Unix timestamps (seconds or milliseconds) to human-readable dates in local time, UTC and ISO 8601, and convert any date back to an epoch timestamp.
Number Base Converter	Convert numbers between binary, octal, decimal, hexadecimal and any custom base from 2 to 36. Supports very large integers with arbitrary precision.
HTML Formatter	Format messy HTML code with clean indentation or minify it to reduce page size. Choose indent size, line wrapping and attribute style. Free online HTML beautifier.
CSS Formatter & Minifier	Beautify messy CSS into readable, indented code or minify stylesheets to make your site load faster. Shows original and minified size and the percentage saved.
JavaScript Minifier	Minify JavaScript with Terser to shrink file size, with options to mangle names and compress code, or beautify minified JS back into readable, indented code.
SQL Formatter	Format and beautify SQL queries online for MySQL, PostgreSQL, SQL Server, SQLite, Oracle, BigQuery and more. Set keyword case and indentation in one click.
Markdown to HTML	Convert Markdown to clean HTML online with a live preview. Supports GitHub Flavored Markdown tables, task lists and code blocks. Copy or download the HTML.
Cron Expression Parser	Translate cron expressions into plain English and see the next run times. Supports ranges, steps, lists and day or month names. Includes common cron presets.
Chmod Calculator	Calculate Linux and Unix file permissions. Convert between numeric (755) and symbolic (rwxr-xr-x) chmod notation with checkboxes, including setuid and sticky bits.
URL Parser	Parse any URL into protocol, host, port, path, query string and fragment. View and edit decoded query parameters in a table and rebuild the URL instantly.