Developer tools that run in your browser
71 tools: encoders, converters, hashes, formatters, and explainers for algorithms and AI models. Nothing you paste is uploaded.
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Pinned
- NATO Phonetic Alphabet Converter
- Binary to Text Converter
- Base64 Encoder & Decoder
- JSON Formatter & Validator
- URL Encoder & Decoder
- JSON to YAML Converter
- QR Code Generator
- UUID Generator
- Password Generator
- JSON to CSV Converter
- SHA-256 Hash Generator
- JWT Decoder
- Pathfinding Visualizer
- MD5 Hash Generator
- SHA-1 Hash Generator
- SHA-512 Hash Generator
- HMAC Generator
- HTML Entity Encoder & Decoder
- JSON to TypeScript
- Sorting Algorithm Visualizer
- Token Counter
- Text Diff
- Markdown to HTML
- Regex Tester
- Graph Algorithms Visualizer
- Word & Character Counter
- JSON Diff
- Hex to Text Converter
- Bcrypt Hash Generator & Checker
- LLM Sampling Explorer
- Unicode Escape Converter
- ASCII Table & Converter
- Case Converter
- HTML Formatter & Minifier
- HTTP Header Lookup
- JSON to XML Converter
- LLM Memory Calculator
- HTTP Status Code Lookup
- YAML Formatter & Validator
- Color Palette Generator
- Timestamp Converter
- XML Formatter & Validator
- Base Converter
- Chmod Calculator
- Color Converter
- TOML to JSON Converter
- Cron Expression Parser
- Semver Range Checker
- SQL Formatter
- IEEE 754 Float Inspector
- Base64 Image Converter
- JSON to Go Struct
- Lorem Ipsum Generator
- Morse Code Translator
- RTK Output Visualizer
- Roman Numeral Converter
- Softmax & Cross-Entropy Calculator
- Cosine Similarity Calculator
- Data Size Converter
- Attention Calculator
- Quantization Calculator
- Unit Converter
- Positional Encoding Visualizer
- ROT13 & Caesar Cipher
- URL Slug Generator
- Whitespace Cleaner
- String Escape / Unescape
- CIDR Calculator
- CSS Minifier & Beautifier
- JS Minifier & Beautifier
- Contrast Checker
Recent
- NATO Phonetic Alphabet Converter
- Binary to Text Converter
- Base64 Encoder & Decoder
- JSON Formatter & Validator
- URL Encoder & Decoder
- JSON to YAML Converter
- QR Code Generator
- UUID Generator
- Password Generator
- JSON to CSV Converter
- SHA-256 Hash Generator
- JWT Decoder
- Pathfinding Visualizer
- MD5 Hash Generator
- SHA-1 Hash Generator
- SHA-512 Hash Generator
- HMAC Generator
- HTML Entity Encoder & Decoder
- JSON to TypeScript
- Sorting Algorithm Visualizer
- Token Counter
- Text Diff
- Markdown to HTML
- Regex Tester
- Graph Algorithms Visualizer
- Word & Character Counter
- JSON Diff
- Hex to Text Converter
- Bcrypt Hash Generator & Checker
- LLM Sampling Explorer
- Unicode Escape Converter
- ASCII Table & Converter
- Case Converter
- HTML Formatter & Minifier
- HTTP Header Lookup
- JSON to XML Converter
- LLM Memory Calculator
- HTTP Status Code Lookup
- YAML Formatter & Validator
- Color Palette Generator
- Timestamp Converter
- XML Formatter & Validator
- Base Converter
- Chmod Calculator
- Color Converter
- TOML to JSON Converter
- Cron Expression Parser
- Semver Range Checker
- SQL Formatter
- IEEE 754 Float Inspector
- Base64 Image Converter
- JSON to Go Struct
- Lorem Ipsum Generator
- Morse Code Translator
- RTK Output Visualizer
- Roman Numeral Converter
- Softmax & Cross-Entropy Calculator
- Cosine Similarity Calculator
- Data Size Converter
- Attention Calculator
- Quantization Calculator
- Unit Converter
- Positional Encoding Visualizer
- ROT13 & Caesar Cipher
- URL Slug Generator
- Whitespace Cleaner
- String Escape / Unescape
- CIDR Calculator
- CSS Minifier & Beautifier
- JS Minifier & Beautifier
- Contrast Checker
Featured
- NATO Phonetic Alphabet ConverterTurn NATO words, or any words, back into letters, or spell text out phonetically.
- Binary to Text ConverterDecode binary to text, or turn text into binary.
- Base64 Encoder & DecoderEncode text to Base64 or decode it back, with URL-safe and file support.
- JSON Formatter & ValidatorFormat, minify, check and repair JSON, with errors shown by line and column.
- URL Encoder & DecoderPercent-encode text for URLs, or decode it back.
- JSON to YAML ConverterConvert JSON to YAML, or YAML to JSON.
- QR Code GeneratorQR codes for links, text and Wi-Fi logins, to print or save as SVG or PNG.
- UUID GeneratorGenerate UUID v4 and v7, one or a thousand at a time.
AI & LLM Tools
- Token CounterCount tokens and see how text is split, with the real GPT-4o and GPT-4 tokenizers.
- LLM Sampling ExplorerSee what temperature, top-k, top-p and min-p do to a model's next-token choices.
- LLM Memory CalculatorHow much GPU memory a model needs: weights plus KV cache, with the maths shown.
- RTK Output VisualizerSee how rtk-style filtering shrinks command output before an AI agent reads it.
- Softmax & Cross-Entropy CalculatorTurn scores into probabilities, and see the loss and perplexity for the right answer.
- Cosine Similarity CalculatorCompare vectors or embeddings: cosine similarity, angle, dot product and distance.
- Attention CalculatorScaled dot-product attention step by step: scores, softmax weights and output.
- Quantization CalculatorWhat int8, int4 and int2 do to model weights: the scale, rounding and error.
- Positional Encoding VisualizerThe sine and cosine pattern a transformer adds to each position, as numbers and a heatmap.
Algorithms
- Pathfinding VisualizerDraw walls and watch A*, Dijkstra, BFS and more find a path, or race two.
- Sorting Algorithm VisualizerWatch quicksort, merge sort and more sort your numbers, and race two side by side.
- Graph Algorithms VisualizerType an edge list and see shortest paths, BFS, DFS, topological order or a spanning tree.
Data Converters
- JSON Formatter & ValidatorFormat, minify, check and repair JSON, with errors shown by line and column.
- JSON to YAML ConverterConvert JSON to YAML, or YAML to JSON.
- JSON to CSV ConverterConvert a JSON array to CSV, or CSV to JSON, with nested keys as columns.
- JSON to TypeScriptPaste JSON, get TypeScript interfaces.
- JSON DiffCompare two JSON documents and see every added, removed and changed value by path.
- JSON to XML ConverterConvert JSON to XML, or XML to JSON, with attributes and repeated elements handled.
- YAML Formatter & ValidatorCheck YAML and tidy its indentation, with comments kept and errors shown by line.
- TOML to JSON ConverterConvert TOML to JSON, or JSON to TOML, with errors shown by line.
- JSON to Go StructPaste JSON, get Go structs with json tags.
Encoding & Decoding
- NATO Phonetic Alphabet ConverterTurn NATO words, or any words, back into letters, or spell text out phonetically.
- Binary to Text ConverterDecode binary to text, or turn text into binary.
- Base64 Encoder & DecoderEncode text to Base64 or decode it back, with URL-safe and file support.
- URL Encoder & DecoderPercent-encode text for URLs, or decode it back.
- QR Code GeneratorQR codes for links, text and Wi-Fi logins, to print or save as SVG or PNG.
- HTML Entity Encoder & DecoderEscape HTML special characters, or decode entities back to text.
- Hex to Text ConverterConvert text to a hex string, or decode hex back to text.
- Unicode Escape ConverterConvert text to \uXXXX Unicode escapes, or decode them back.
- ASCII Table & ConverterLook up decimal and hex ASCII codes, or convert text to character codes.
- Base64 Image ConverterConvert an image to a Base64 data URI, or preview one from pasted Base64.
- Morse Code TranslatorText to Morse code and back, and hear it played.
- ROT13 & Caesar CipherShift letters around the alphabet: ROT13, or any Caesar shift from 1 to 25.
Hashing & Crypto
- UUID GeneratorGenerate UUID v4 and v7, one or a thousand at a time.
- Password GeneratorRandom passwords from 4 to 128 characters, made with the Web Crypto API.
- SHA-256 Hash GeneratorGet the SHA-256 hash of text or a file, and check it against an expected one.
- JWT DecoderDecode a JWT, check its HS256 signature, or make a test token.
- MD5 Hash GeneratorGet the MD5 checksum of text or a file, and check it against an expected one.
- SHA-1 Hash GeneratorGet the SHA-1 hash of text or a file, and check it against an expected one.
- SHA-512 Hash GeneratorGet the SHA-512 hash of text or a file, and check it against an expected one.
- HMAC GeneratorSign text with a secret key: HMAC-SHA256, SHA-512, SHA-1 or MD5.
- Bcrypt Hash Generator & CheckerHash a password with bcrypt, or check a password against a bcrypt hash.
Text Tools
- Text DiffCompare two texts line by line or word by word, highlighted live.
- Markdown to HTMLPreview Markdown as you type and copy the HTML, with tables and task lists.
- Regex TesterTest a regex against your text, with live highlights and a replace preview.
- Word & Character CounterWords, lines and three kinds of character count.
- Case ConvertercamelCase, PascalCase, snake_case, kebab-case and more, all at once.
- Lorem Ipsum GeneratorPlaceholder text by the paragraph or the word.
- URL Slug GeneratorTurn a title into a URL-safe slug.
- Whitespace CleanerRemove trailing spaces, mixed line endings and extra blank lines.
- String Escape / UnescapeEscape or unescape text for JavaScript, JSON, SQL, shell or CSV.
Numbers & Units
- Color Palette GeneratorBuild color schemes from one color: complementary, analogous, triadic and more.
- Timestamp ConverterUnix timestamp to date, and back, in UTC and your local time.
- Base ConverterBinary, octal, decimal and hex, all at once.
- Chmod CalculatorUnix permissions as octal (755) and letters (rwxr-xr-x), with what each one allows.
- Color ConverterHex, RGB, HSL, CMYK and OKLCH, with a contrast check.
- IEEE 754 Float InspectorThe bits and exact value of any float or double, such as 0.1 + 0.2.
- Roman Numeral ConverterNumbers to Roman numerals, and back, 1 to 3999.
- Data Size ConverterBytes, KB/MB/GB and KiB/MiB/GiB, all at once.
- Unit ConverterLength, weight, volume, area, speed, time or temperature, with every unit at once.
- CIDR CalculatorNetwork, broadcast and usable host range, for IPv4 and IPv6.
Web Dev Utilities
- HTML Formatter & MinifierIndent HTML so it reads well, or minify it without changing how it renders.
- HTTP Header LookupLook up an HTTP header, or paste response headers to have each one explained.
- HTTP Status Code LookupEvery HTTP status code, what it means and when to use it.
- XML Formatter & ValidatorFormat, minify and check XML, with errors shown by line and column.
- Cron Expression ParserAny cron expression in plain English, with its next five run times.
- Semver Range CheckerWhat ^1.2.3 or ~1.2 means in plain words, and which versions it allows.
- SQL FormatterFormat SQL with consistent indentation and keyword case, for eight dialects.
- CSS Minifier & BeautifierMinify CSS, or format minified CSS with indentation.
- JS Minifier & BeautifierMinify JavaScript with Terser, or format minified code with indentation.
- Contrast CheckerCheck WCAG contrast between two colors, and get a fix when it fails.