# Zerethon Tools

> Free, privacy-friendly utilities for creators and developers. Every tool runs entirely in the browser unless explicitly noted — no uploads, no signup, no ads.

## Policy

- AI crawlers and assistants are welcome to index, summarize, and cite tool pages.
- Each tool page exposes Schema.org WebApplication / FAQPage / BreadcrumbList JSON-LD.
- Machine-readable registry: https://tools.zerethon.com/tools.json
- Sitemap: https://tools.zerethon.com/sitemap.xml

## Tool API (callable by agents)

Deterministic tools run server-side and return plain text — no browser needed. Stateless, no auth, no cookies.

- Discovery (JSON, lists params): https://tools.zerethon.com/api/raw
- Run: `GET` or `POST https://tools.zerethon.com/api/raw/{slug}?input=...` (or send the input as the request body)
- Available now: json-formatter, base64-encoder, url-encoder, hash-generator, html-entities-converter, text-case-converter, slugify-url-generator, uuid-generator, rot13-encoder, string-hex-converter, number-base-converter, html-stripper, sort-lines, deduplicate-lines, word-counter
- Example: https://tools.zerethon.com/api/raw/hash-generator?algo=sha256&input=hello

## Tools

- [JSON Formatter](https://tools.zerethon.com/json-formatter): Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.
- [SQL Formatter](https://tools.zerethon.com/sql-formatter): Format SQL queries online — beautify MySQL, PostgreSQL, SQLite, SQL Server, Oracle, and BigQuery.
- [UUID Generator](https://tools.zerethon.com/uuid-generator): Generate UUIDs online — v1, v4, v7, and Nil. Bulk generation up to 10,000. Free, no signup.
- [YouTube Thumbnail Downloader](https://tools.zerethon.com/youtube-thumbnail-downloader): Download YouTube thumbnails in all available resolutions. Just paste a video URL.
- [Open Graph Preview](https://tools.zerethon.com/open-graph-preview): Test how your URL appears when shared on social media. Preview Facebook, Twitter, LinkedIn, and Slack cards.
- [NFT Metadata Validator](https://tools.zerethon.com/nft-metadata-validator): Validate NFT metadata against ERC-721, OpenSea, and Solana Metaplex standards. Preview your NFT before minting.
- [Password Generator](https://tools.zerethon.com/password-generator): Generate strong, cryptographically random passwords. Configurable length and character sets — runs in your browser.
- [Word & Character Counter](https://tools.zerethon.com/word-counter): Count words, characters, sentences, and paragraphs. Reading time, speaking time, and top keywords — instant.
- [Text Case Converter](https://tools.zerethon.com/text-case-converter): Convert text between 14 cases — UPPER, lower, Title, Sentence, camelCase, snake_case, kebab-case, CONSTANT_CASE, and more.
- [Lorem Ipsum Generator](https://tools.zerethon.com/lorem-ipsum-generator): Generate Lorem Ipsum placeholder text — by paragraphs, sentences, or words. Optional HTML wrapping.
- [Base64 Encoder & Decoder](https://tools.zerethon.com/base64-encoder): Encode and decode Base64 text or files. Supports standard and URL-safe variants. Free, no signup.
- [URL Encoder & Decoder](https://tools.zerethon.com/url-encoder): Encode and decode URLs and query string parameters. Percent-encoding for safe transmission.
- [Slugify URL Generator](https://tools.zerethon.com/slugify-url-generator): Turn any text into a clean URL slug. Transliterates diacritics, strips punctuation, optional stopword removal.
- [Reverse Text Generator](https://tools.zerethon.com/reverse-text-generator): Reverse text by character, word, or line. Grapheme-cluster safe — emoji and combining sequences stay intact.
- [Markdown Table Generator](https://tools.zerethon.com/markdown-table-generator): Build GitHub Flavored Markdown tables in a live grid. Paste TSV or CSV, set alignment per column.
- [Remove Line Breaks](https://tools.zerethon.com/remove-line-breaks): Remove or replace line breaks in text. Three modes — replace with space, keep paragraphs, or strip all.
- [Whitespace Remover](https://tools.zerethon.com/whitespace-remover): Clean extra spaces, tabs, and blank lines. Optional zero-width Unicode strip catches sneaky invisible characters.
- [UTM Builder](https://tools.zerethon.com/utm-builder): Build campaign-tagged URLs for Google Analytics, GA4, Plausible, PostHog. Validates URL and saves your last 5 locally.
- [Fancy Text Generator](https://tools.zerethon.com/fancy-text-generator): Convert text into 13 Unicode font styles — bold, italic, script, fraktur, double-struck, monospace, fullwidth. Works on Twitter, IG, TikTok, Discord.
- [Invisible Text Generator](https://tools.zerethon.com/invisible-text-generator): Generate invisible Unicode characters for Discord, gaming, and platforms that require non-empty input. Six variants.
- [Strikethrough Text Generator](https://tools.zerethon.com/strikethrough-text-generator): Add Unicode strikethrough, underline, or overline to any text. Copy-paste to bios, posts, comments.
- [Small Text Generator](https://tools.zerethon.com/small-text-generator): Convert text to Unicode small caps, superscript, or subscript. ᴄᴏᴘʏ ᴀɴᴅ ᴘᴀsᴛᴇ ᴀɴʏᴡʜᴇʀᴇ.
- [Upside Down Text Generator](https://tools.zerethon.com/upside-down-text-generator): Flip text upside down with Unicode mirrored characters. Great for fun captions and bios.
- [Zalgo Text Generator](https://tools.zerethon.com/zalgo-text-generator): Glitch your text with stacked combining diacritics. Mild for subtle creep, chaos for full Zalgo.
- [HTML Formatter & Minifier](https://tools.zerethon.com/html-formatter): Beautify or minify HTML in your browser. Pure client-side — your markup never leaves your device.
- [CSS Formatter & Minifier](https://tools.zerethon.com/css-formatter): Beautify or minify CSS rules instantly in your browser. Free, no signup, no upload.
- [YAML Formatter & Validator](https://tools.zerethon.com/yaml-formatter): Validate, reformat, and minify YAML in your browser. Catches syntax errors with line numbers.
- [XML Formatter](https://tools.zerethon.com/xml-formatter): Beautify or minify XML using your browser's native parser. No dependencies, fast and accurate.
- [Markdown Formatter](https://tools.zerethon.com/markdown-formatter): Reformat Markdown with Prettier. Consistent spacing, list markers, and link layout.
- [JavaScript Formatter & Minifier](https://tools.zerethon.com/javascript-formatter): Beautify with Prettier or minify in your browser. Supports modern syntax — async/await, optional chaining, JSX.
- [CSV to JSON Converter](https://tools.zerethon.com/csv-to-json): Convert CSV (or TSV / pipe-separated) data to JSON. Auto-detects delimiter, RFC 4180 compliant.
- [JSON to CSV Converter](https://tools.zerethon.com/json-to-csv): Convert a JSON array of objects to CSV. Optional dot-path flatten for nested data.
- [JSON to YAML Converter](https://tools.zerethon.com/json-to-yaml): Convert JSON to YAML in your browser. YAML 1.2 spec.
- [YAML to JSON Converter](https://tools.zerethon.com/yaml-to-json): Convert YAML to JSON in your browser. Catches syntax errors with parser messages.
- [JSON to XML Converter](https://tools.zerethon.com/json-to-xml): Convert JSON to XML in your browser. Configurable root element, attribute prefix, and text key.
- [MD5 Hash Generator](https://tools.zerethon.com/md5-hash-generator): Compute MD5 digest of text or files (up to 50 MB) in your browser. Output in hex or Base64.
- [SHA-256 Hash Generator](https://tools.zerethon.com/sha256-hash-generator): Compute SHA-256 digest of text or files in your browser using Web Crypto API. Output in hex or Base64.
- [SHA-1 Hash Generator](https://tools.zerethon.com/sha1-hash-generator): Compute SHA-1 digest of text or files in your browser using Web Crypto API. Useful for Git commit hashes and legacy systems.
- [ROT13 Encoder](https://tools.zerethon.com/rot13-encoder): Classic ROT13 cipher in your browser. Encoding and decoding are the same operation.
- [Caesar Cipher](https://tools.zerethon.com/caesar-cipher): Encrypt and decrypt with the classic Caesar shift cipher. Includes auto-detect using English letter frequency.
- [JPG to PNG Converter](https://tools.zerethon.com/jpg-to-png): Convert JPG to lossless PNG entirely in your browser. Files never upload.
- [PNG to JPG Converter](https://tools.zerethon.com/png-to-jpg): Convert PNG to JPG in your browser with quality control. Files never upload.
- [WebP Converter](https://tools.zerethon.com/webp-converter): Convert WebP ↔ JPG / PNG in your browser. Files never upload. Smaller files for the modern web.
- [Image Compressor](https://tools.zerethon.com/image-compressor): Shrink JPG, PNG, or WebP files. Before/after size shown side-by-side. Files never upload.
- [Image Resizer](https://tools.zerethon.com/image-resizer): Resize images by width, height, percentage, or exact dimensions. Aspect ratio lock. Files never upload.
- [Timezone Converter](https://tools.zerethon.com/timezone-converter): Convert any date and time between IANA timezones. DST-aware, shareable, runs entirely in your browser.
- [Wallet Address Validator](https://tools.zerethon.com/wallet-address-validator): Validate Ethereum, Bitcoin (legacy + SegWit), Solana, TRON and Litecoin addresses. Format + checksum, no RPC.
- [ETH Unit Converter](https://tools.zerethon.com/eth-unit-converter): Convert between Wei, Gwei, Ether, Szabo, Finney and more. BigInt-safe — no rounding errors.
- [EIP-55 Checksum Tool](https://tools.zerethon.com/eip55-checksum): Convert any Ethereum address to its canonical EIP-55 checksummed form. Detect typos before sending funds.
- [Keccak-256 Hash Generator](https://tools.zerethon.com/keccak256-hash-generator): Compute Keccak-256 digest (Ethereum's hash) of text or files. Different from SHA-3 — matches Solidity keccak256().
- [Base58 Encoder & Decoder](https://tools.zerethon.com/base58-encoder): Encode and decode Base58 and Base58Check. Supports text or hex input, used by Bitcoin, Solana, and IPFS.
- [Hash Generator — All Algorithms](https://tools.zerethon.com/hash-generator): Compute MD4, MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3, Keccak-256, CRC-32 and NTLM hashes of text or files in your browser.
- [AES Encrypt & Decrypt](https://tools.zerethon.com/aes-encrypt-decrypt): Encrypt and decrypt text with AES-256-GCM and a password. PBKDF2-SHA256 key derivation, runs entirely in your browser.
- [Base-N Encoder & Decoder](https://tools.zerethon.com/base-n-encoder): Encode and decode Base16, Base32 (RFC 4648), Base32 Crockford, Base85 (ASCII85), and Base91 in your browser.
- [UTF-8 Converter](https://tools.zerethon.com/utf8-converter): Convert text to UTF-8 hex bytes, decimal bytes, \xAB or \u{HEX} escape sequences — and back.
- [HTML Entities Converter](https://tools.zerethon.com/html-entities-converter): Encode and decode HTML entities — named, decimal, and hex. 250+ HTML5 entities included.
- [Escape & Unescape](https://tools.zerethon.com/escape-unescape): Escape and unescape strings for HTML, XML, Java, C#, JavaScript, JSON, CSV (RFC 4180), and SQL.
- [Number Base Converter](https://tools.zerethon.com/number-base-converter): Convert numbers between decimal, binary, octal and hexadecimal in a live 4-row grid. BigInt-safe with optional signed 32 / 64-bit mode.
- [Bitwise Calculator](https://tools.zerethon.com/bitwise-calculator): AND, OR, XOR, NAND, NOR, XNOR, NOT and shift operations on two BigInt operands. Results shown in decimal, binary, octal and hex at once.
- [IP Notation Converter](https://tools.zerethon.com/ip-notation-converter): Convert IPv4 and IPv6 between dotted, decimal integer, hex, octal, binary, and canonical / expanded forms. Auto-detects the input format.
- [String to Hex Converter](https://tools.zerethon.com/string-hex-converter): Convert text to UTF-8 hex bytes and back. Pick from five separators on encode; decode auto-strips any common separator.
- [String to Binary Converter](https://tools.zerethon.com/string-binary-converter): Convert text to 8-bit binary and back. UTF-8 aware with optional byte and nibble spacing for readability.
- [ASCII Converter](https://tools.zerethon.com/ascii-converter): Convert characters to ASCII / Unicode codepoints in decimal, hex, binary and octal — or render a live table for any input string.
- [Remove Accents](https://tools.zerethon.com/remove-accents): Strip diacritics from any text — café → cafe, naïve → naive. Optional German / Nordic transliteration (ä → ae, ß → ss, å → aa).
- [Deduplicate Lines](https://tools.zerethon.com/deduplicate-lines): Remove duplicate lines from a list. Case-sensitive toggle, trim before compare, keep first or last, optional sort.
- [Sort Lines](https://tools.zerethon.com/sort-lines): Sort lines alphabetically, numerically, by length, or just reverse. Locale-aware, case-insensitive and unique options.
- [Filter Lines](https://tools.zerethon.com/filter-lines): Keep or remove lines matching a substring or regex pattern. Invert match, case-insensitive, trim before match.
- [Text Repeater](https://tools.zerethon.com/text-repeater): Repeat text 1–10000 times. Modes: whole block, per line, or per word. Separator picker with custom option.
- [Word Frequency Counter](https://tools.zerethon.com/word-frequency-counter): Count word occurrences with rank, count, and percent. Stopword filter, top-N selector, CSV export of the full table.
- [Remove Punctuation](https://tools.zerethon.com/remove-punctuation): Strip Unicode punctuation and symbols from text. Optional keep apostrophes, hyphens, periods; whitespace collapse.
- [Delimited Text Extractor](https://tools.zerethon.com/delimited-text-extractor): Extract one column from CSV, TSV, or any delimited text. Pick by column number or header name. RFC 4180 compliant.
- [XML to JSON Converter](https://tools.zerethon.com/xml-to-json): Convert XML to JSON in your browser. Native DOMParser with configurable attribute prefix, text key, and compact mode.
- [CSV to XML Converter](https://tools.zerethon.com/csv-to-xml): Convert CSV (or TSV / pipe-separated) data to XML. Configurable root and record element names. Header row becomes column tags.
- [CSV to SQL Converter](https://tools.zerethon.com/csv-to-sql): Generate INSERT statements from CSV. MySQL, PostgreSQL, SQLite, or SQL Server dialect, with optional CREATE TABLE.
- [HTML Stripper](https://tools.zerethon.com/html-stripper): Strip HTML tags and decode entities to plain text. Toggles for line breaks, links, and whitespace preservation.
- [HTML Table Extractor](https://tools.zerethon.com/html-table-extractor): Extract <table> elements from HTML into CSV, TSV, JSON, or Markdown. Picks individual tables when the page has more than one.
- [HTML to Markdown Converter](https://tools.zerethon.com/html-to-markdown): Convert HTML to Markdown using Turndown. ATX or Setext headings, bullet style, code-fence style — fully customizable.
- [Markdown to HTML Converter](https://tools.zerethon.com/markdown-to-html): Render Markdown to HTML with live preview. GFM tables, task lists, fenced code blocks. Powered by marked.
- [Color Converter](https://tools.zerethon.com/color-converter): Convert colors between HEX, RGB / RGBA, HSL, HSV, and CMYK in a live grid. Swatch preview and CSS named-color lookup.
- [Unit Converter](https://tools.zerethon.com/unit-converter): Convert between length, weight, volume, area, time, temperature, speed, data size, and angle units. Live grid across every unit in the dimension.
- [Date Calculator](https://tools.zerethon.com/date-calculator): Add or subtract years, months, weeks, days, hours and minutes to a date — or compute the difference between two dates with business-day count.
- [Unix Timestamp Converter](https://tools.zerethon.com/unix-timestamp-converter): Convert Unix timestamps (seconds or milliseconds) to ISO, UTC, RFC 2822, local, and relative formats. Live "Now" panel.
- [Crontab Translator](https://tools.zerethon.com/crontab-translator): Translate a cron expression to plain English and preview the next 5 fire times. Supports standard 5-field and 6-field with seconds.
- [URL Parser](https://tools.zerethon.com/url-parser): Break a URL into scheme, credentials, host, port, path, query and hash. Percent-decoded query parameters in a live table.
- [Python Formatter](https://tools.zerethon.com/python-formatter): Clean up Python indentation, collapse blank lines, normalize string quotes. Indentation cleaner, not full PEP-8.
- [PHP Formatter](https://tools.zerethon.com/php-formatter): Reformat PHP source in your browser. PSR-12-friendly defaults, brace-style toggle, opener normalization.
- [Java Formatter](https://tools.zerethon.com/java-formatter): Reindent Java source with K&R or Allman brace style. Pure client-side, no compile.
- [C# Formatter](https://tools.zerethon.com/csharp-formatter): Reindent C# source with Allman braces, auto-property normalization, and expression-bodied member tidy-up. Indentation tidy, not a full Roslyn format.
- [C / C++ Formatter](https://tools.zerethon.com/c-cpp-formatter): Reindent C or C++ source — brace style, indent width, and preprocessor placement controls. Indentation tidy, not a full clang-format.
- [Ruby / Lua / Perl Formatter](https://tools.zerethon.com/ruby-lua-perl-formatter): Reindent Ruby, Lua, or Perl source. One tool, three keyword-driven languages.
- [GraphQL Formatter](https://tools.zerethon.com/graphql-formatter): Pretty-print GraphQL queries, mutations, and SDL using the official graphql/language parser.
- [CSS Preprocessor Converter](https://tools.zerethon.com/css-preprocessor-converter): Convert between LESS, SCSS, SASS, Stylus, and CSS. Real compilers for "to CSS" paths, heuristics for the rest.
- [Text Diff](https://tools.zerethon.com/text-diff): Compare two blocks of text — side-by-side, inline, or unified patch. Line, word, or character granularity.
- [JSON Diff](https://tools.zerethon.com/json-diff): Structural JSON comparison. Color-coded paths for added, removed, and changed keys. Optional ignore-array-order mode.
- [JSONPath Tester](https://tools.zerethon.com/jsonpath-tester): Test JSONPath expressions against your JSON. Live evaluator with path and value results, filters, slices, recursive descent.
- [XPath Tester](https://tools.zerethon.com/xpath-tester): Test XPath expressions against XML or HTML using your browser's native XPath engine. Live results table.
- [Regex Data Generator](https://tools.zerethon.com/regex-data-generator): Generate 1–100 strings that match any regex pattern. Great for test data, fixtures, and fuzzing.
- [JSON5 Validator](https://tools.zerethon.com/json5-validator): Validate JSON5 with line and column error reporting. Supports comments, trailing commas, single quotes, hex numbers.
- [JSON to Java POJO](https://tools.zerethon.com/json-to-java): Generate a Java POJO from JSON. Toggles for Jackson annotations, Lombok, or Java 16+ records. Nested objects become nested classes.
- [POJO to JSON](https://tools.zerethon.com/pojo-to-json): Convert a Java POJO (Plain Old Java Object) instance into JSON using Jackson, Gson, or Moshi. Copy-paste-ready code recipes plus the reverse converter when you need to scaffold the POJO itself.
- [Line Chart Maker](https://tools.zerethon.com/line-chart-maker): Paste CSV, get a live line chart. Multi-series, smooth curve slider, PNG export. Free, runs in your browser.
- [Bar Chart Maker](https://tools.zerethon.com/bar-chart-maker): Build bar charts from CSV — stacked, grouped, horizontal. Multi-series, PNG export, no upload.
- [Pie Chart Maker](https://tools.zerethon.com/pie-chart-maker): Two-column CSV in, pie chart out. Auto-coloured slices, PNG export, pure client-side.
- [Doughnut Chart Maker](https://tools.zerethon.com/doughnut-chart-maker): Doughnut chart from CSV — perfect for KPI slides with a hollow centre. PNG export, no upload.
- [Scatter Plot Maker](https://tools.zerethon.com/scatter-plot-maker): Scatter plot from CSV — first column X, every following column a Y series. PNG export, runs in your browser.
- [Random JSON Generator](https://tools.zerethon.com/random-json-generator): Generate fake JSON from a schema using faker.js. Multi-output: JSON, CSV, TSV, XML. Free, runs in your browser.
- [Random Number Generator](https://tools.zerethon.com/random-number-generator): Generate cryptographically random integers — range, count, unique-only and decimal / binary / octal / hex output.
- [Random Name Picker](https://tools.zerethon.com/random-name-picker): Paste a list, pick N at random. Unique-only mode, repeatable draws. Great for raffles, team assignments and lunch picks.
- [JavaScript Obfuscator](https://tools.zerethon.com/js-obfuscator): Obfuscate JavaScript with control-flow flattening, string array, dead-code injection and identifier mangling. Three presets, runs in your browser.
- [JavaScript Minifier](https://tools.zerethon.com/javascript-minifier): Minify JavaScript with terser. Mangle, compress, comment policies — and a before / after size comparison.
- [HTML Minifier](https://tools.zerethon.com/html-minifier): Minify HTML with html-minifier-terser. Collapses whitespace, removes comments, inline CSS / JS minification. Size savings shown live.
- [HTML Playground](https://tools.zerethon.com/html-playground): Live HTML / CSS / JS playground with sandboxed iframe preview. Auto-saves to localStorage. Pure client-side.
- [Bubble Sort Visualizer](https://tools.zerethon.com/bubble-sort-visualizer): Animated bubble sort with step controls, speed, custom input, live comparison/swap counters and pseudocode. Runs entirely in your browser.
- [Insertion Sort Visualizer](https://tools.zerethon.com/insertion-sort-visualizer): Animated insertion sort with step controls, speed, custom input, live comparison/write counters and pseudocode. Runs in your browser.
- [Selection Sort Visualizer](https://tools.zerethon.com/selection-sort-visualizer): Animated selection sort with step controls, speed, custom input, live comparison/swap counters and pseudocode. Runs in your browser.
- [Merge Sort Visualizer](https://tools.zerethon.com/merge-sort-visualizer): Animated merge sort with step controls, speed, custom input, live comparison/write counters and pseudocode. Runs in your browser.
- [Quick Sort Visualizer](https://tools.zerethon.com/quick-sort-visualizer): Animated quicksort with pivot/partition highlights, step controls, speed, custom input, live counters and pseudocode. Runs in your browser.
- [Heap Sort Visualizer](https://tools.zerethon.com/heap-sort-visualizer): Animated heap sort with step controls, speed, custom input, live comparison/swap counters and pseudocode. Runs in your browser.
- [Binary Search Visualizer](https://tools.zerethon.com/binary-search-visualizer): Animated binary search over a sorted array with target input, step controls, speed, live comparison counter and pseudocode. Runs in your browser.
- [Linear Search Visualizer](https://tools.zerethon.com/linear-search-visualizer): Animated linear search with target input, step controls, speed, live comparison counter and pseudocode. Works on unsorted data. Runs in your browser.
- [Dijkstra's Algorithm Visualizer](https://tools.zerethon.com/dijkstra-visualizer): Interactive Dijkstra pathfinding on a grid — draw walls, move start/goal, generate mazes, step through the search. Runs in your browser.
- [A* Pathfinding Visualizer](https://tools.zerethon.com/a-star-pathfinding-visualizer): Interactive A* pathfinding on a grid with a Manhattan heuristic — draw walls, move start/goal, generate mazes, step through the search. Runs in your browser.
- [Breadth-First Search (BFS) Visualizer](https://tools.zerethon.com/breadth-first-search-visualizer): Interactive breadth-first search on a grid — draw walls, move start/goal, generate mazes, step through the level-by-level expansion. Runs in your browser.
- [Depth-First Search (DFS) Visualizer](https://tools.zerethon.com/depth-first-search-visualizer): Interactive depth-first search on a grid — draw walls, move start/goal, generate mazes, step through the deep-dive exploration. Runs in your browser.
- [Maze Generator](https://tools.zerethon.com/maze-generator): Animated maze generator using recursive division — step through the wall carving, adjust speed, regenerate. Pairs with the pathfinding visualizers. Runs in your browser.
- [Binary Search Tree Visualizer](https://tools.zerethon.com/binary-search-tree-visualizer): Interactive binary search tree — insert, search, delete with an animated tree, step controls and pseudocode. Runs in your browser.
- [Binary Heap Visualizer](https://tools.zerethon.com/heap-visualizer): Interactive binary max-heap — insert and extract-max with animated sift-up / sift-down, step controls and pseudocode. Runs in your browser.
- [Stack Visualizer](https://tools.zerethon.com/stack-visualizer): Interactive LIFO stack — push and pop with an animated top pointer and step controls. Runs in your browser.
- [Queue Visualizer](https://tools.zerethon.com/queue-visualizer): Interactive FIFO queue — enqueue and dequeue with animated front/rear pointers and step controls. Runs in your browser.
- [Linked List Visualizer](https://tools.zerethon.com/linked-list-visualizer): Interactive singly linked list — insert head/tail, search, delete with animated pointer traversal and step controls. Runs in your browser.
- [Hash Table Visualizer](https://tools.zerethon.com/hash-table-visualizer): Interactive hash table with separate chaining — insert, search, delete with animated hashing and collision chaining. Runs in your browser.
- [Sieve of Eratosthenes Visualizer](https://tools.zerethon.com/sieve-of-eratosthenes): Animated Sieve of Eratosthenes on a number grid — marks primes and crosses out composites, with step controls. Runs in your browser.
- [Euclidean Algorithm (GCD) Visualizer](https://tools.zerethon.com/euclidean-gcd-visualizer): Animated Euclidean algorithm — compute the GCD of two numbers step by step with the (a, b) → (b, a mod b) reduction. Runs in your browser.
- [Prime Factorization Visualizer](https://tools.zerethon.com/prime-factorization): Animated prime factorization as a factor tree — splits a number into prime factors step by step. Runs in your browser.
- [Collatz Conjecture Visualizer](https://tools.zerethon.com/collatz-conjecture): Animated Collatz (3n+1) sequence as a line chart — watch the trajectory climb and fall to 1. Step controls. Runs in your browser.
- [Fibonacci Sequence Visualizer](https://tools.zerethon.com/fibonacci-visualizer): Animated Fibonacci sequence — each term is the sum of the previous two, built iteratively with step controls. Runs in your browser.
- [Convex Hull Visualizer](https://tools.zerethon.com/convex-hull-visualizer): Animated convex hull (Andrew’s monotone chain) on a plane of points — push/pop construction with step controls. Runs in your browser.
- [Polygon Area Visualizer (Shoelace)](https://tools.zerethon.com/polygon-area-calculator): Animated polygon area with the shoelace formula — sums signed triangle areas with step controls. Runs in your browser.
- [Line Segment Intersection Visualizer](https://tools.zerethon.com/line-intersection): Animated line segment intersection — cross-product orientation tests plus the exact crossing point, with step controls. Runs in your browser.
- [Tower of Hanoi Visualizer](https://tools.zerethon.com/tower-of-hanoi): Animated recursive Tower of Hanoi solver — moves disks in the minimum 2ⁿ−1 steps with step controls. Runs in your browser.
- [N-Queens Visualizer](https://tools.zerethon.com/n-queens-visualizer): Animated N-Queens backtracking on a chessboard — try, place, conflict, and backtrack with step controls. Runs in your browser.
- [0/1 Knapsack Visualizer](https://tools.zerethon.com/knapsack-visualizer): Animated 0/1 knapsack dynamic programming — fills the DP table cell by cell, highlighting dependencies, with step controls. Runs in your browser.
- [Conway’s Game of Life](https://tools.zerethon.com/game-of-life): Interactive Conway’s Game of Life — draw cells, play generations, step, randomize. Runs entirely in your browser.
- [Percentage Calculator](https://tools.zerethon.com/percentage-calculator): Three-in-one percentage calculator: X% of Y, X as a % of Y, and % increase/decrease. Instant, client-side.
- [Scientific Calculator](https://tools.zerethon.com/scientific-calculator): Online scientific calculator — trig, log, powers, roots, factorial, π/e, DEG/RAD, with a proper expression parser. Client-side.
- [Fraction Calculator](https://tools.zerethon.com/fraction-calculator): Add, subtract, multiply and divide fractions with automatic simplification, decimal and mixed-number output. Client-side.
- [Combinations & Permutations Calculator](https://tools.zerethon.com/combinatorics-calculator): Exact nCr, nPr and n! with big-integer precision. Client-side, no signup.
- [Roman Numeral Converter](https://tools.zerethon.com/roman-numeral-converter): Two-way Roman numeral converter (1–3999) with full validation. Client-side.
- [Statistics Calculator](https://tools.zerethon.com/statistics-calculator): Descriptive statistics — mean, median, mode, range, variance, SD, quartiles (sample & population). Client-side; data never leaves your device.
- [Citation Generator](https://tools.zerethon.com/citation-generator): Generate APA 7, MLA 9, Chicago and Harvard citations for websites, books and journals — reference + in-text. Client-side.
- [GPA Calculator](https://tools.zerethon.com/gpa-calculator): Credit-weighted GPA on the 4.0 scale — add courses, grades and credits. Client-side; grades stay private.
- [Grade Calculator](https://tools.zerethon.com/grade-calculator): Weighted grade from categories, plus “what do I need on the final”. Client-side.
- [Pomodoro Timer](https://tools.zerethon.com/pomodoro-timer): Pomodoro focus timer with automatic work/break cycling, custom durations, chime and notifications. Settings saved locally.
- [Molar Mass Calculator](https://tools.zerethon.com/molar-mass-calculator): Molar mass / molecular weight from a chemical formula (parentheses + hydrates) with a per-element breakdown. Client-side.
- [Interactive Periodic Table](https://tools.zerethon.com/periodic-table): Interactive, searchable periodic table — 118 elements with atomic mass, number and category colors. Client-side.
- [Significant Figures Calculator](https://tools.zerethon.com/significant-figures-calculator): Count significant figures and round to N sig figs, with ambiguous trailing-zero detection. Client-side.
- [Scientific Notation Converter](https://tools.zerethon.com/scientific-notation-converter): Convert numbers between decimal, scientific, E-notation and engineering notation. Client-side.
- [Compound Interest Calculator](https://tools.zerethon.com/compound-interest-calculator): Compound interest with any frequency plus recurring deposits — future value, interest and contributions. Client-side.
- [Loan / EMI Calculator](https://tools.zerethon.com/loan-emi-calculator): Monthly payment (EMI), total interest and total repaid for a fixed-rate loan or mortgage. Client-side.
- [Tip & Split Calculator](https://tools.zerethon.com/tip-split-calculator): Tip calculator and bill splitter — tip %, total, and per-person amounts. Client-side.
- [Equation Solver](https://tools.zerethon.com/equation-solver): Solve quadratics (real/complex roots + discriminant) and 2×2 linear systems. Client-side.
- [Matrix Calculator](https://tools.zerethon.com/matrix-calculator): Add, subtract, multiply, transpose matrices and find determinant & inverse (2×2 to 4×4). Client-side.
- [Truth Table Generator](https://tools.zerethon.com/truth-table-generator): Generate a full truth table from a boolean expression (AND/OR/NOT/XOR/→/↔), up to 8 variables. Client-side.
- [LCM & GCD Calculator](https://tools.zerethon.com/lcm-gcd-calculator): Greatest common divisor and least common multiple of any list of integers, exact. Client-side.
- [Readability Checker](https://tools.zerethon.com/readability-checker): Flesch Reading Ease and Flesch–Kincaid grade level, with word/sentence/syllable stats. Client-side; text never leaves your device.
- [Reading Time Calculator](https://tools.zerethon.com/reading-time-calculator): Estimate reading and speaking time from text, with adjustable WPM. Client-side.
- [Word & Page Counter](https://tools.zerethon.com/essay-word-page-counter): Live word/character/sentence/paragraph counts and a page estimate for essays. Client-side; your writing stays private.
- [Z-Score Calculator](https://tools.zerethon.com/z-score-calculator): Convert a value to a z-score and a z-score to a percentile (standard normal). Client-side.
- [Probability Calculator](https://tools.zerethon.com/probability-calculator): Single events, independent AND/OR, and the binomial distribution P(X=k)/P(X≤k)/P(X≥k). Client-side.
- [Function Grapher](https://tools.zerethon.com/function-grapher): Plot y = f(x) for any expression over a custom range — powers, trig, logs, roots. Client-side.
- [Linear Regression Calculator](https://tools.zerethon.com/linear-regression-calculator): Least-squares best-fit line with r and R² and a live scatter plot. Client-side; your data stays private.
- [Vector Calculator](https://tools.zerethon.com/vector-calculator): Add, subtract, dot, cross, magnitude, unit vector and angle for 2D/3D vectors. Client-side and instant.
- [Set Operations Calculator](https://tools.zerethon.com/set-operations-calculator): Union, intersection, difference, symmetric difference plus subset/superset checks. Duplicates removed automatically.
- [Random Group Generator](https://tools.zerethon.com/random-group-generator): Fairly split a class or team into random groups by count or by size. Re-roll any time. Client-side.
- [Exam Countdown Timer](https://tools.zerethon.com/exam-countdown-timer): Live countdown to your exam, deadline or test. Label and date saved on your device. Client-side.
- [Flashcards Maker](https://tools.zerethon.com/flashcards-maker): Build flashcard decks and study them shuffled with a score. Saved locally — no account needed.
- [Standard Deviation Calculator](https://tools.zerethon.com/standard-deviation-calculator): Mean, variance and sample/population standard deviation with the full working shown. Client-side and private.
- [Physics Kinematics Calculator](https://tools.zerethon.com/physics-kinematics-calculator): SUVAT motion, projectile, Ohm’s law and ideal gas solvers in one place. Enter what you know, get the rest.
- [Karnaugh Map Solver](https://tools.zerethon.com/karnaugh-map-solver): Minimise 2–4 variable Boolean functions to simplest SOP with don’t-care support. Shows prime implicants.
- [Derivative & Integral Calculator](https://tools.zerethon.com/derivative-integral-calculator): Symbolic first and second derivatives plus a numeric definite integral (Simpson’s rule). Client-side.

## Categories

- Developer — 73 tools
- Creator — 33 tools
- Web3 — 6 tools
- Algorithm — 31 tools
- Math — 19 tools
- Writing — 4 tools
- Productivity — 6 tools
- Science — 5 tools
- Finance — 3 tools

## Category landing pages

- Developer Tools: https://tools.zerethon.com/developer-tools
- Creator Tools: https://tools.zerethon.com/creator-tools
- Web3 Tools: https://tools.zerethon.com/web3-tools
- Algorithm Tools: https://tools.zerethon.com/algorithm-tools
- Math Tools: https://tools.zerethon.com/math-tools
- Writing Tools: https://tools.zerethon.com/writing-tools
- Productivity Tools: https://tools.zerethon.com/productivity-tools
- Science Tools: https://tools.zerethon.com/science-tools
- Finance Tools: https://tools.zerethon.com/finance-tools

## Learning hub

Plain-language explanations with Big-O analysis, linking to the matching interactive visualizers. Hub: https://tools.zerethon.com/learn

- Graph Algorithms: https://tools.zerethon.com/learn/graph-algorithms — Understand how graphs are traversed and how shortest paths are found. Visualize breadth-first search, depth-first search, Dijkstra and A* pathfinding step by step.
- Sorting Algorithms: https://tools.zerethon.com/learn/sorting-algorithms — See how sorting algorithms work and why they differ in speed. Visualize bubble, insertion, selection, merge, quick and heap sort with step-by-step animations.
- Searching Algorithms: https://tools.zerethon.com/learn/searching-algorithms — Learn how searching algorithms find a value in a collection. Compare linear search and binary search and see why sorting unlocks O(log n) lookups.
- Data Structures: https://tools.zerethon.com/learn/data-structures — Explore the core data structures behind every program: stacks, queues, linked lists, binary search trees, heaps and hash tables — visualized and explained.
- Dynamic Programming: https://tools.zerethon.com/learn/dynamic-programming — Understand dynamic programming and recursion: how overlapping subproblems and optimal substructure turn exponential brute force into efficient solutions.
- Number Theory: https://tools.zerethon.com/learn/number-theory — Explore the number theory that powers algorithms: prime sieves, the Euclidean GCD, prime factorization and famous sequences like the Collatz conjecture.
- Practice with Games: https://tools.zerethon.com/learn/practice-games — Turn theory into practice with free educational games: typing speed, mental math drills, flashcards and knowledge quizzes on game.zerethon.com.