Free online utilities
yutils
Developer and everyday tools that run entirely in your browser. Your data never leaves your device.
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62- Base64 Encode / DecodeEncode
Encode text to Base64 or decode Base64 back to text. Runs entirely in your browser, no data sent to any server.
- URL Encode / DecodeEncode
Percent-encode text for safe use in URLs, or decode percent-encoded URLs back to text. Runs entirely in your browser.
- UUID / ULID GeneratorEncode
Generate UUID v4 (random), UUID v7 (time-ordered, RFC 9562), or ULID identifiers — all client-side via crypto.
- JSON Formatter / ValidatorText
Format, validate, and minify JSON strings. Adjust indent and optionally sort keys. Runs entirely in your browser.
- JWT DecoderEncode
Decode the header and payload of a JSON Web Token. Signature is not verified (a public key is required). The token is processed entirely in your browser.
- JWT Encoder (HMAC)Encode
Generate a signed JSON Web Token with HS256/HS384/HS512 (HMAC-SHA). Payload and secret stay in your browser — Web Crypto API based.
- SHA HashEncode
Compute SHA-1, SHA-256, SHA-384, or SHA-512 hash of text. Uses the browser's Web Crypto API; no data is sent to any server.
- Hex Encode / DecodeEncode
Encode text to hexadecimal or decode hex back to text. Supports UTF-8 multi-byte characters and tolerates whitespace.
- HTML Entity Encode / DecodeEncode
Encode HTML special characters (&, <, >, ", ') to entities, or decode named/numeric entities back to text.
- String Case ConverterText
Convert strings between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and Title Case — all six cases shown side-by-side.
- Unix Timestamp ConverterTime
Convert between Unix timestamps (seconds/milliseconds) and ISO 8601 / UTC / locale time. Auto-detects input.
- Color ConverterMedia
Convert colors between HEX, RGB, and HSL with a live preview swatch. Auto-detects any of the three input formats.
- Regex TesterText
Test JavaScript regular expressions with live match results. Supports g/i/m/s/u/y flags and capture groups.
- Image to Base64 (Data URI)Media
Convert an image file to a Base64 data URI for inline embedding in HTML/CSS/Markdown. Up to 5 MB.
- Markdown PreviewText
Render Markdown to HTML side-by-side. Supports CommonMark + GFM (tables, fenced code, task lists). marked is lazy-loaded.
- HTML → MarkdownText
Convert HTML into Markdown. Headings, lists, links, code, tables, blockquotes. Uses the browser's DOMParser — accurate, 0 dependency.
- YAML ↔ JSONText
Convert between YAML and JSON. Tolerates comments and multiline strings on the YAML side. yaml is lazy-loaded.
- QR Code GeneratorMedia
Generate a QR code from any text or URL. Adjustable error correction (L/M/Q/H), SVG output, downloadable.
- Cron Expression ParserTime
Translate a cron expression into human-readable text and preview the next 5 run times. Locale-aware.
- Cron Expression BuilderTime
Build a cron expression visually — pick minute / hour / day / month / weekday from presets or free input. Preview human-readable text and next 5 run times.
- Text DiffText
Compare two texts and highlight added/removed lines, words, or characters.
- JSON DiffText
Compare two JSON values, with optional key sorting and JSON-aware error messages.
- Password GeneratorEncode
Generate cryptographically strong passwords, tokens, random strings, and passphrases with entropy display.
- CSV ↔ JSONText
Convert between CSV and JSON. Handles quoted fields, custom delimiters, and header rows.
- Number Base ConverterEncode
Convert numbers between bases (binary/octal/decimal/hex/base36) using BigInt for large integers. Auto-detects 0b/0o/0x prefixes.
- SQL FormatterText
Format SQL queries with proper indentation and keyword casing. Supports PostgreSQL, MySQL, SQLite, and standard dialects.
- XML FormatterText
Pretty-print or minify XML with attribute preservation. Handles SOAP, sitemaps, and config files.
- XML ↔ JSONText
Convert between XML and JSON with attribute and element handling.
- URL ParserEncode
Decompose a URL into protocol, host, path, query parameters, and hash — read-only inspection.
- Smart PasteText
Paste any text and get tool recommendations — JSON, JWT, Base64, URL, UUID, Cron, and 9 more types auto-detected.
- Lorem IpsumText
Generate placeholder text in words, sentences, or paragraphs. Classic Lorem Ipsum or randomized.
- HMAC GeneratorEncode
Compute HMAC (Hash-based Message Authentication Code) with SHA-1/256/384/512 using the Web Crypto API.
- HMAC VerifyEncode
Verify whether a given HMAC signature matches the message + secret. Constant-time comparison via Web Crypto API.
- MD5 HashEncode
Compute MD5 hash for text. Note: MD5 is broken for security — checksums and legacy compatibility only.
- JSON PathText
Query JSON with JSONPath expressions ($.store.book[*].author etc.) and inspect matches.
- Punycode (IDN)Encode
Convert international domain names to/from Punycode (xn-- encoded ASCII). Uses native URL parser.
- HTTP Status CodesEncode
Browse and search HTTP status codes (1xx-5xx) with descriptions and common usage.
- User-Agent ParserEncode
Parse User-Agent strings into browser, OS, device, and engine fields.
- Bcrypt HashEncode
Hash passwords with Bcrypt or verify a plaintext against an existing hash. Configurable salt rounds.
- JSON Schema ValidatorText
Validate JSON data against a JSON Schema (Draft 2020-12). Powered by Ajv with format support.
- JSON Schema GeneratorText
Generate a JSON Schema (Draft 2020-12) from a sample JSON. Infer types, required fields, and nested structures automatically.
- HTML FormatterText
Beautify or minify HTML with proper indentation, attribute alignment, and configurable wrap.
- CSS FormatterText
Beautify or minify CSS with proper indentation. Configurable selector and property style.
- JavaScript FormatterText
Beautify or minify JavaScript with brace style and indent options. Powered by js-beautify.
- TOML ↔ JSONText
Convert between TOML (Tom's Obvious Minimal Language) and JSON. Used in Cargo.toml, pyproject.toml, etc.
- Cookie ParserEncode
Parse Cookie or Set-Cookie strings into a table. Decode percent-encoded values. Supports Set-Cookie attributes (Path/Domain/Max-Age/SameSite/HttpOnly/Secure).
- INI ↔ JSONText
Convert INI configuration to JSON and back. Supports sections, comments (; or #), and key=value.
- IP / CIDR CalculatorEncode
Compute network address, broadcast, host range, mask, and host count from an IPv4 + CIDR.
- cURL BuilderEncode
Build cURL commands from URL/method/headers/body. Auto-detects JSON content-type.
- Time Zone ConverterTime
Convert datetime between IANA time zones using the browser's Intl API.
- Date FormatterTime
Format a date with patterns (YYYY-MM-DD HH:mm:ss). Live preview of common formats.
- JSON → TypeScriptText
Generate TypeScript interfaces from a JSON sample. Nested objects become separate interfaces.
- JS Object → JSONText
Convert a JavaScript object literal (unquoted keys, single quotes, trailing commas, comments) into standard JSON. Lenient parser, strict output.
- Slug GeneratorText
Convert text into a URL-safe slug. Configurable separator, lowercase, and accent stripping.
- ASCII TreeText
Convert indented text or path list into a box-drawing tree (├── │ └──).
- Diff PatchText
Generate a unified diff (-u) patch from two text inputs. Compatible with `git apply` / `patch -p0`.
- Mock DataText
Generate fake JSON records — names, emails, UUIDs, dates, and more. 0 dependency.
- MongoDB Extended JSONText
Convert MongoDB Extended JSON (EJSON) between Canonical and Relaxed forms, or strip BSON wrappers to plain JSON. Recognizes 16 wrapper types ($oid/$date/$numberLong/$numberDecimal/$binary/...).
- Color Contrast CheckerMedia
Check the WCAG contrast ratio between two colors. Pass/fail for AA Normal/Large + AAA Normal/Large with a live sample.
- Color Palette GeneratorMedia
Generate a palette from a single base color — shades, tints, complement, analogous, triad, tetrad. HSL-based. 0 dependency.
- CSS Gradient GeneratorMedia
Build linear, radial, and conic CSS gradients with color stops + angle/position. Live preview + copy-ready CSS.
- Date CalculatorTime
Four modes — duration between two dates, date ± N days, days → Y/M/D breakdown, and a persistent D-day list.