Algorithms & Computer Science Tools

Encode UTF-8 text as hex or binary, or decode hex/binary back. Spaces in hex are ignored. Binary is 8-bit groups. Nothing is sent anywhere.

Uncompressed WAV/AIFF size = sample rate × channels × (bit depth ÷ 8) × seconds. MP3/AAC size ≈ bitrate × seconds ÷ 8. Headers are a few kilobytes — ignored here.

Encode text to Base64 (standard or URL-safe), hexadecimal, binary, HTML entities, Unicode escapes or ROT13 — and decode back. Full UTF-8 and emoji support. Live in both directions; nothing leaves y...

Clean a list of links before sharing or archiving them. Removes recognized campaign trackers while keeping the destination, useful query parameters, and URL fragment. It does not open links, follow...

Why does an O(n²) algorithm feel instant for 10 items but crawl for a million? Watch each complexity class grow, and see how long each would really take at one operation per nanosecond — the number...

Everything on a computer is bits. Tap the cells to flip bits and see the number change, then run the bitwise operations — AND, OR, XOR, NOT, shifts — that power everything from colours to cryptogra...

Plan numbered filenames while preserving extensions, spot duplicate names, and copy an old-to-new mapping before renaming files yourself.

Convert file sizes with SI (1000) or binary IEC (1024) prefixes. Hard-drive boxes use decimal GB; Windows historically used 1024 and still called them GB. Edit any field.

One row of cells and one rule decides the next row from each cell's three neighbours. Rule 30 churns out pure randomness, Rule 90 grows a Sierpinski triangle, and Rule 110 is powerful enough to com...

Encrypt like the Romans and the Victorians: Caesar shifts, Atbash mirrors, ROT13 and the Vigenère key cipher. Then watch the “crack” button undo a Caesar cipher in one click — because letter freque...

Test color contrast ratios against WCAG 2.2 accessibility standards (AA / AAA) and simulate color-vision deficiencies in real time.

Emit Access-Control-* headers for a simple or preflight response. * plus credentials is invalid. Prefer an explicit origin in production.

Construct cron expressions with interactive dials, read instant plain-English explanations, and preview the next 10 trigger times.

Build a Content-Security-Policy header from plain fields, or paste an existing policy to find quoting mistakes and common weaknesses. Nothing is fetched or sent.

Paste a selector. Counts IDs, classes/attributes/pseudo-classes, and types/pseudo-elements as (A, B, C). :not() is ignored as a class; its argument is counted. :is() / :where() / :has() take the mo...

Paste CSV, TSV or a JSON array and convert it to JSON, CSV, Markdown table, HTML table or SQL INSERT statements. Handles quoted fields, custom delimiters and header detection. Everything stays in y...

CSS transition-timing-function: cubic-bezier(x1, y1, x2, y2). x is time (0–1), y is progress (can overshoot). Copy the declaration after you like the motion. Respects reduced-motion.

Six words from a 256-word list, picked with crypto.getRandomValues (~48 bits). Not the official 7,776-word EFF list — treat this as a strong memorable password, then store it in a manager. Generate...

Paste a list: drop duplicate lines, sort A→Z or Z→A, trim spaces, ignore case. Stays in this browser — mailing lists and log dumps never leave the device.

Paste an email’s raw headers to inspect the visible From, Reply-To and Return-Path domains, reported SPF/DKIM/DMARC results, and the number of Received hops. Everything is checked in this page; no ...

Open a CSV in Excel and it silently eats leading zeros, turns long IDs into 1.23E+15, makes “1-2” into 2-Jan and gene names like MARCH1 into dates. This finds every cell Excel would mangle and expo...

Paste names copied from a file list. Preview Windows-reserved characters and device names, trailing dots/spaces, Unicode normalization, and case-insensitive collisions before you share or move the ...

Tick the stacks you use. Output is a combined .gitignore — copy into the repo root. Git still tracks files you already committed; git rm --cached those separately.

Generate cryptographic hashes instantly. Supports MD5, SHA-1, SHA-256, SHA-384, SHA-512. All processing happens in your browser — nothing is sent to any server.

Build 301/302 redirect snippets for Apache (.htaccess) or Nginx (server { }): HTTP→HTTPS, www/apex canonical hosts and page redirects. Review before deploying — a bad rule loops a site (test Nginx ...

Strip comments and collapse idle whitespace in HTML or CSS. Not a full parser — keep <pre> and <textarea> out of the input, and do not minify JavaScript here. Local only.

Escape text for safe HTML display, decode named or numeric entities, and inspect the characters in a string. Choose readable entities for the five HTML-sensitive characters or numeric entities for ...

A practical subset: headings, paragraphs, links, images, lists, bold/italic, code, blockquotes, hr. Scripts and styles are dropped. Not a full CommonMark round-trip.

Look up any HTTP status code, filter by class, and copy a one-line explanation. Covers the registered 1xx–5xx codes developers hit in the wild. Entirely offline.

Type any text and watch it get smaller: common letters get short codes, rare ones get long codes, and the result is the exact same idea behind ZIP, PNG and MP3. The tree is the codebook, drawn for ...

Check an International Bank Account Number with the ISO 13616 MOD-97 algorithm, then pretty-print it in groups of four. This confirms the check digits only — it cannot prove an account exists.

Make a .ics file any calendar app can import. Times are written as floating local (no time-zone math). All-day events use DATE values.

32-bit binary32 (float) and 64-bit binary64 (double) bit patterns via typed arrays. Paste a decimal, hex (0x…) or 32/64-bit 0/1 string.

Drop in a photo, logo or screenshot and hover to read any pixel as HEX, RGB and HSL — with a magnifier for precision. The tool also pulls out the image's dominant palette, ready to copy as CSS vari...

Code that won’t compile, a password that “is definitely right”, a search that finds nothing, a spreadsheet match that fails: the culprit is often a character you cannot see. Reveals zero-width spac...

Validate an ISBN-10 or ISBN-13, compute the check digit, and convert between the two. Hyphens and spaces are ignored. Check digits follow the ISBN / EAN rules — this does not look up a book.

Nested objects become dotted keys (user.address.city); arrays use items.0. Unflatten rebuilds the tree. Runs in this page — nothing is uploaded.

Decode and audit JSON Web Tokens offline. Zero network calls — your security tokens never leave your browser.

Press any key to test it live — handy when a laptop key died or a layout is fighting you. Shows event.key, event.code, keyCode, which, modifiers, location, and ready-to-copy event listener code. No...

Build bash scripts from common patterns — select blocks, customize, and copy the complete script

Visually set file permissions — toggle read/write/execute for owner, group, and others. Get octal, symbolic, and the full command

Searchable reference of 200+ Linux commands — filter by category, copy with one click

Calculate partition sizes, plan disk layouts, convert units, and get the commands to set it all up

Paste log output to get instant analysis, or generate commands to search, filter, and monitor logs

Complete reference of Linux signals, process states, and process management commands with examples

Build SSH, SCP, and SSH tunnel commands — fill in the options, copy the command

Generate systemd .service unit files — fill in the details, get a complete service file with install instructions

Validate or generate a Luhn (mod 10) check digit. Used by card numbers, IMEI, NPI and some barcodes. This only tests the checksum — it cannot tell you whether a number is issued, active or real.

Make a correctly encoded mailto: link with recipients, cc, bcc, subject and a multi-line body — as a URL, HTML or Markdown — or decode one you found. Runs in your browser.

Interactive spreadsheet grid editor to create, format, and convert tables to GitHub-flavored Markdown, ASCII box art, Unicode borders, HTML, and CSV.

Check everything before the call: see your microphone level move, hear a tone from the left and right speaker, and preview your camera with its real resolution. Audio and video stay inside this tab...

Convert a file extension to a MIME type, or a MIME type back to common extensions. Handy when writing Content-Type headers, nginx maps or <input accept> lists. Lookup is local.

Turn “café”, “don’t” and “привет” back into real text. Reverses UTF-8 misread as Windows-1252 or Latin-1, even when it happened twice or only in parts of the text. Runs in your browser.

URL-safe IDs from crypto.getRandomValues. Default alphabet is A–Za–z0–9_- (64 symbols). Collision odds are about (n²) / (2 × 64^size) for n IDs — this is not a password manager.

Watch a tiny neural network learn XOR — the task that killed the first wave of neural networks, because a straight line can't separate the points. As it trains, the decision boundary curls into a c...

See which trackers and third parties a web page talks to. Load a HAR export from your browser's DevTools, or paste page source, and get a local report. Nothing you load is uploaded.

Draw walls and watch four search algorithms hunt for the goal: DFS wanders, BFS floods evenly, Dijkstra matches BFS on a uniform grid, and A* heads straight for the target. The visited cells and th...

Convert CSS lengths between pixels, rem and em for a chosen root and parent font size. Defaults to the browser 16 px root. Copy-ready declarations, no build step.

Split a URL or a raw ?a=1&b=2 into keys. Duplicate keys become arrays. Build the other way from JSON. Uses the platform URLSearchParams — stays on this device.

The same Fibonacci function, two ways: naive recursion recomputes the same subproblems a staggering number of times, while memoization remembers each answer once. Watch the call tree fill with dupl...

Compare two Semantic Versioning 2.0.0 strings, then bump major, minor, patch or a pre-release. Precedence follows the spec: major.minor.patch, then pre-release identifiers, build metadata ignored.

Convert any text into URL-friendly slugs. Perfect for blog posts, filenames, and SEO-friendly URLs.

Watch six classic sorting algorithms race on the same shuffled data — see exactly why O(n²) sorts crawl while merge and quick sort fly. Every comparison and swap is counted live.

Check the syntax of an SPF or DMARC DNS record you paste, count SPF DNS lookups, or build a new record. Works offline: nothing is looked up or sent.

Shift every HH:MM:SS,mmm timestamp in an .srt by milliseconds (negative to go earlier). Runs in this page — files stay on your device.

Subtitles start in sync and slowly slide out of time? That is drift, not an offset — usually a 23.976 vs 25 fps mismatch — and a plain time shift can’t fix it. Give two lines with their correct tim...

Minify and clean SVG markup, remove metadata, editor bloat and unused namespaces, round decimal precision, preview live, and copy optimized SVG.

Paste anything and get it back in every case at once: UPPER, lower, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, aLtErNaTiNg, reversed and URL ...

Move the stack from peg A to peg C, never putting a bigger disk on a smaller one. The catch: the optimal solution is 2ⁿ − 1 moves, so 8 disks means 255 moves — recursion made visible. Solve it your...

Generate truth tables for logical expressions. Supports AND, OR, NOT, XOR, IMPLIES, and IFF operators.

Convert text to Unicode code points, HTML entities, and escape sequences. Supports all Unicode characters.

Convert Unix epoch timestamps (seconds, milliseconds, microseconds or nanoseconds — auto-detected) to human dates and back. Shows UTC, your local time, ISO 8601, relative time and the weekday. A li...

Percent-encode or decode any text (full encodeURIComponent or URL-safe encodeURI), and break a URL into protocol, host, port, path, hash and an editable table of query parameters. Edit a value and ...

Inspect your browser's user agent string, client hints, screen geometry, GPU WebGL renderer, touch capabilities, color depth, and networking status.

Generate one or hundreds of UUID v4s, time-ordered UUID v7s, ULIDs, NanoIDs, short IDs or custom-pattern codes using the browser's cryptographic random source. Choose case, braces and separators, t...

Build a vCard 3.0 you can save as .vcf and open on a phone. Stays in the browser — no address book is uploaded.

Estimate video file size from duration and video/audio bitrates, or solve for the bitrate that fits a size budget. Formula: size ≈ (video + audio) × time. Container overhead is ignored.

Calculate exact file download and upload durations, test bandwidth capacity for simultaneous 4K streams and video calls, and estimate mobile data cap exhaustion.

Format, minify, validate, and explore XML. Paste messy XML, get clean indented output with syntax highlighting.