Data, Markup & Code Tools
Format, validate and convert the data and markup that research and coursework produce — JSON, YAML, XML, CSV, HTML, Markdown and LaTeX — test regular expressions, decode tokens and URLs, work through binary and networking exercises, and generate hashes, UUIDs and QR codes. Everything runs in your browser, so pasted data stays on your device.
Data, Markup & Code
38 tools · free, no sign-up
JSON Formatter & Validator
Format, validate, and beautify JSON data. Minify or pretty-print JSON with syntax highlighting and error detection.
CSV to Table Converter
Convert CSV data into formatted tables. Preview your data as an HTML table and copy it for use in documents, reports, or web pages.
Text to URL Slug Converter
Convert any text into a clean, URL-friendly slug. Remove special characters, replace spaces with hyphens, and generate SEO-friendly URLs instantly.
HTML Tag Remover
Remove all HTML tags from text and extract clean plain text. Perfect for cleaning up content copied from web pages, emails, or CMS editors.
Markdown to Plain Text
Convert Markdown-formatted text to clean plain text. Remove headers, bold, italics, links, lists, and other Markdown syntax while preserving readability.
Text Encoder & Decoder
Encode and decode text in multiple formats: URL encoding, Base64, HTML entities, and Unicode escape sequences. Convert between formats instantly.
Markdown Table Generator
Build Markdown tables visually or from pasted CSV/TSV data — with column alignment options and properly padded output.
Text to Hex Converter
Convert text to hexadecimal and hex back to text — UTF-8 aware, with byte grouping options and instant copy.
ASCII Code Converter
Convert text to ASCII character codes and codes back to text — decimal by default, with an ASCII reference table included.
Hash Generator (SHA-256)
Generate SHA-256, SHA-384, SHA-512, and SHA-1 hashes of any text — computed locally in your browser with the Web Crypto API. Nothing is uploaded.
CSV to JSON Converter
Convert CSV data to JSON and JSON arrays back to CSV — with header detection, delimiter options, and pretty-printed output.
XML Formatter & Validator
Format, indent, and validate XML — pretty-print messy markup, catch syntax errors, and minify for compact output.
HTML to Markdown Converter
Convert HTML to clean Markdown — headings, lists, links, bold, italics, code, and tables — right in your browser.
UUID Generator
Generate random UUIDs (v4) — one or in bulk — using your browser's cryptographic randomness. Copy individually or all at once.
Unicode Character Inspector
Break text into grapheme clusters and code points with official Unicode names, categories, scripts and blocks, UTF-8 and UTF-16 encodings, and HTML, JS and CSS escapes.
QR Code Generator
Make a QR code from text, a web address or a DOI — versions 1–40, error correction L to H, masks scored by penalty — with colours, margin and SVG or PNG download.
Markdown to HTML Converter
Convert Markdown to HTML by the CommonMark rules, with GitHub tables, strikethrough and bare links, raw HTML escaped or allowlist-filtered, and a live preview.
HTML Formatter
Beautify or minify HTML without changing how it renders — pre, textarea, script and style kept exactly — and list unclosed, mismatched and stray tags by line.
LaTeX Table Generator
Turn pasted CSV or TSV, or a grid you type, into LaTeX tabular code — alignment, booktabs or line rules, caption, label, threeparttable notes, characters escaped.
LaTeX Equation Editor
Type LaTeX math or build it from a toolbar, see it rendered live, and copy the LaTeX, MathML that Word pastes as an equation, or an HTML snippet.
LaTeX Symbol Finder
Search over 600 LaTeX math and text symbols by name, command, character or code point, with each one's Unicode character and the package that defines it.
Regex Tester
Test JavaScript regular expressions live: highlighted matches with positions and groups, flags, a replacement preview, a token-by-token explanation and ready-made patterns.
Rich Text to LaTeX Converter
Paste from Word, Google Docs or a web page and get LaTeX: headings, bold and italic, lists, tables and links mapped to standard commands, with every special character escaped.
LaTeX to Unicode Converter
Convert LaTeX to Unicode text and back: Greek letters, superscripts, subscripts, mathematical alphabets, accents, fractions and roots, with unconverted commands listed.
SQL Formatter
Beautify or minify SQL: one clause per line, indented subqueries, your keyword case, indentation and comma style, with notes for PostgreSQL, MySQL, SQL Server and SQLite.
YAML to JSON Converter
Convert YAML to JSON and JSON to YAML with validation: errors name the line and column, key order is kept, and YAML 1.1 gotchas such as NO and 1.10 are flagged.
XML to JSON Converter
Convert XML to JSON and JSON to XML with the attribute, text and array conventions you choose, a live sample of the mapping, and line-numbered errors.
URL Parser
Break a URL into scheme, host, port, path segments, query parameters and fragment, decode every parameter into a table, then edit and rebuild the address.
JWT Decoder
Decode a JSON Web Token's header and payload in your browser, read exp, nbf and iat as dates, and see warnings. It decodes and never claims to verify.
Image to Base64 Converter
Convert an image to a Base64 data URI, HTML, CSS or Markdown snippet with the size overhead shown, or decode Base64 back to an image you can preview and download.
Binary Calculator
Add, subtract, multiply and divide binary numbers with the carries, borrows and long division shown, plus AND, OR, XOR, NOT, shifts and rotates at 4 to 128 bits.
Two's Complement Calculator
Convert signed integers to two's complement and back at 4 to 64 bits, with invert-and-add-one working, the value range, overflow wrap-around and sign extension.
IEEE 754 Floating Point Converter
Convert decimals to half, single and double precision bits and back: sign, exponent, fraction, the exact stored value, subnormals, NaN payloads and rounding error.
Hamming Code Calculator
Encode Hamming (7,4) and general (n,k) codes with every parity check shown, inject bit errors, and decode with the syndrome table, plus a SECDED overall parity option.
IP Subnet Calculator
IPv4 CIDR and IPv6 prefix calculator: network, broadcast, host range, subnet and wildcard masks, RFC 1918 and special ranges flagged, and splitting into subnets.
Sorting Algorithm Visualizer
Step through bubble, insertion, selection, merge, quick and heap sort on your own numbers, with comparisons, swaps and writes counted and all six compared.
Color Converter
Convert HEX, RGB, HSL, HWB, HSV and CMYK colors, plus OKLCH, with a picker, the nearest CSS color name and copy-ready CSS custom properties.
Color Contrast Checker
Check the WCAG 2.2 contrast ratio of a text and background color, see AA and AAA results for normal and large text, and get the nearest passing colors.
Data, Markup and LaTeX
- Structured data. The JSON Formatter & Validator, XML Formatter & Validator, CSV to JSON Converter and CSV to Table Converter; the YAML to JSON Converter and XML to JSON Converter work both ways and report the line and column of any error. The SQL Formatter beautifies or minifies queries for standard SQL, PostgreSQL, MySQL, SQL Server and SQLite.
- Markup. Markdown to HTML by the CommonMark rules, HTML to Markdown, Markdown to Plain Text, the HTML Formatter, the HTML Tag Remover and the Markdown Table Generator.
- LaTeX. The LaTeX Table Generator, the LaTeX Equation Editor, which also copies MathML that Word pastes as an equation, and the LaTeX Symbol Finder. The Rich Text to LaTeX Converter turns text pasted from Word or Google Docs into compile-ready LaTeX, and the LaTeX to Unicode Converter goes the other way for plain-text contexts.
Text, Web and Computer Science
| Task | Tool |
|---|---|
| Find the syntax error in an API response | JSON Formatter & Validator |
| Turn a spreadsheet export into JSON | CSV to JSON Converter |
| Convert a config file between YAML and JSON | YAML to JSON Converter |
| Check a pattern before using it in code | Regex Tester |
| Split a URL into parts and read its query parameters | URL Parser |
| Read what is inside a login token | JWT Decoder |
| Encode or decode URL, Base64 and HTML entities | Text Encoder & Decoder |
| See what a character really is | Unicode Character Inspector, ASCII Code Converter, Text to Hex Converter |
| Get the SHA-256 digest of a string, or a unique ID | Hash Generator, UUID Generator |
| Make a clean URL slug from a title | Text to URL Slug Converter |
| Link a poster or slide to a paper | QR Code Generator with the article's DOI |
| Work binary arithmetic and signed numbers | Binary Calculator, Two's Complement Calculator |
| See why 0.1 + 0.2 is not 0.3 in code | IEEE 754 Floating Point Converter |
| Practise error-correcting codes and networking | Hamming Code Calculator, IP Subnet Calculator |
| Compare how sorting algorithms behave | Sorting Algorithm Visualizer |
| Convert a colour or check its contrast for accessibility | Color Converter, Color Contrast Checker |
Local, Standards-Based Processing
Paste a configuration file, an API key in a JSON body or unpublished data, and it stays on your machine: the formatters, converters and generators run in your browser and send nothing to a server. The hash and UUID generators use the browser's Web Crypto API rather than a home-made random source.
The tools follow the published specifications where one exists — RFC 8259 for JSON, CommonMark for Markdown, RFC 4122 for version 4 UUIDs, IEEE 754 for floating point — and the Regex Tester uses JavaScript's regular expression engine, so a pattern that works there may need adjusting for Python, PCRE or another flavor. For plain text clean-up without code — case, line breaks, duplicates — see Text Cleanup & Formatting, and for ciphers and encodings such as Base32, Codes & Ciphers.
Frequently Asked Questions
- Why does my JSON fail validation?
- The usual causes are a trailing comma after the last item, single quotes instead of double quotes, unquoted keys, and comments, none of which strict JSON allows. Paste the JSON into the JSON Formatter & Validator to see the parser's error message, then check the characters around it.
- Why does my YAML not convert to JSON?
- YAML is strict about indentation: it uses spaces, never tabs, and a key indented one space too far or too few changes the structure or breaks it. Unquoted values such as yes, no or 1.0 may also be read as booleans or numbers rather than strings. The YAML to JSON Converter shows the line and column of the first error.
- Is decoding a JWT the same as verifying it?
- No. A JSON Web Token's header and payload are only Base64url-encoded JSON, which anyone can read; decoding proves nothing about who issued the token. Verification checks the signature with the right key, and must be done by your server. The JWT Decoder shows the claims and expiry dates and says what it has not verified.
- Why does 0.1 + 0.2 equal 0.30000000000000004?
- Computers store numbers in binary, and 0.1 and 0.2 have no exact binary representation, just as 1/3 has no exact decimal one. The stored values are very slightly off, and their sum rounds to a double that prints as 0.30000000000000004. The IEEE 754 Floating Point Converter shows the exact stored value and the rounding error.
- How many hosts are in a /24 subnet?
- A /24 IPv4 network has 28 = 256 addresses, of which 254 can be assigned to hosts, because the first is the network address and the last is the broadcast address. The IP Subnet Calculator gives the range, masks and splits for any prefix, in IPv4 and IPv6.
- Is it safe to paste sensitive data into these tools?
- The tools process what you paste in your browser and do not upload it. That said, treat secrets as secrets: rotate any key or token you have pasted somewhere you did not intend, and avoid working with production credentials on a shared computer.