Data, developer, and design tools in one place

Convert Markdown to HTML in your browser with a live preview, side-by-side view, and copy or export options. Processing stays on the page.

Convert HTML to Markdown in your browser while preserving common structure such as headings, lists, tables, and links. Useful for migrating web content into editable documents.

Remove duplicate lines from multiline text with options to ignore case, trim edges, keep first-seen order, and review frequency stats. Processing stays in your browser.

Format, minify, sort, and validate JSON in your browser. Parsing errors include location details, and your data never leaves the page.

Encode and decode Base64 in the browser, with standard and URL-safe variants, automatic direction detection, and optional file-to-Base64 conversion. Useful for API debugging and local data prep.

Convert Unix timestamps and date-times in your browser. Supports seconds, milliseconds, and microseconds with auto-detection, shows local and UTC time side by side, and can generate a timestamp from a date picker for log triage and API debugging.

Generate UUID v4 values in your browser with batch size and format options such as uppercase, no hyphens, and braces. Randomness comes from the native crypto API for test data and unique identifiers.

Parse a URL into protocol, host, port, path, query, and hash fields, and list each query parameter name and value. Useful for debugging API URLs and share links.

Generate a QR code from text or a URL in your browser. Adjust size and colors, then export an image for event entry points, landing pages, posters, and print materials. Content stays on this page and is not uploaded.

Build, parse, and CRC16-check Modbus RTU and TCP (MBAP) frames in your browser. Covers common function codes FC01–FC16 for coils and registers used in industrial IoT debugging.

Convert plain text into leetspeak (1337) with basic, advanced, and expert substitution levels. Runs locally for playful usernames, samples, and demos.

Render input as multiple Unicode mathematical and stylistic letterforms for bios, titles, and decorative labels. Copy individual styles.

Improve bilingual copy readability by adding Chinese–English spacing, splitting long sentences, and optionally converting English punctuation to Chinese forms.

Reformat Markdown tables so columns pad to a consistent visual width, keep :---: alignment markers, and account for full-width characters such as Chinese for readable source layouts.

Infer TypeScript interface definitions from JSON in your browser. Nested objects become separate interfaces, with options for the root name, optional fields, readonly, export, and type aliases.

View JSON and NDJSON logs as a collapsible, syntax-colored tree. Expand or fold nodes to inspect deep structured logs locally in the browser.

Mask sensitive JSON fields in your browser by matching key names such as password, token, or phone. Nested objects and arrays are walked recursively, and values are replaced with mask characters so you can share debug payloads more safely.

Strip common tracking parameters such as utm_*, spm, fbclid, and gclid from links, and extract URLs from surrounding text first when needed. Useful for tidying share links and reducing tracker noise. Cleanup runs locally in the browser.

Convert cURL commands into JavaScript fetch code. Parses -X, -H, and --data-raw into method, headers, and body, with optional async/await wrapping.

Generate RSA key pairs in the browser with the Web Crypto API at 1024, 2048, or 4096 bits and export standard PEM text. Private keys are not sent over the network. Intended for development, testing, and learning—not as a production key-management system.

Decode JWTs locally into readable Header and Payload JSON. Tokens never leave the browser.

Paste page HTML to extract title, description, keywords, and Open Graph / Twitter preview fields locally. Useful for SEO checks and competitive page reviews.

Tokenize English and Chinese text locally, rank frequent terms, and calculate density after stop-word filtering. Useful for on-page focus checks and over-optimization review.

Convert RMB numeric amounts into Chinese capital letters for finance forms. Handles consecutive zeros, jiao/fen, and the trailing 整 (zheng) rule, accepts thousand separators and negatives, and supports up to 13 integer digits—useful for contracts, invoices, and expense claims. The capitalized output stays in Chinese by design.

Compute safe request rates from quota limits and time windows. Add safety margins to estimate per-request delay and total batch duration without hitting 429 responses.

Estimate compressed transfer size for HTML or JSON text using Shannon entropy heuristics. Compare raw vs gzip and brotli ratios without deploying a server.

Search HTTP status codes from 100 to 511 with plain-language meanings, typical causes, and fix hints. Filter by class and copy individual cards locally.

Diagnose cross-origin issues and generate Access-Control headers for Nginx, Node.js/Express, and Apache. Highlights invalid combinations such as credentials with wildcard origins.

Inline SVG into a CSS background-image: url(...) string using URI encoding or Base64. Useful for small icons you want to keep in CSS instead of separate asset files.

Combine blur, grayscale, contrast, and related CSS filter functions with live preview. Drag sliders to build stacks such as filter: blur(2px) grayscale(100%); and copy the result.

Apply color-vision deficiency matrices to a sample view so you can preview how protanopia, deuteranopia, tritanopia, or achromatopsia may change UI colors. Use it to catch contrast and status-color issues before shipping.

Resize and re-encode images locally with Canvas. Set max dimensions, quality, and output format, then download the result. Original files stay in the browser and are not uploaded.

Set column and row counts plus gaps to generate a basic display:grid layout. Preview the track structure, try quick templates, and copy CSS or HTML for admin layouts and card grids.

Browse Tailwind CSS color scales (including 50–950 steps) on one board. Search by name, scale, or HEX, then copy utility class names or raw HEX values for CSS projects.

Paste CSS declarations and map them to Tailwind utility classes where possible. Common layout, spacing, and color rules become standard classes; unmatched values fall back to arbitrary-value syntax.

Convert HTML snippets to React JSX in the browser. Rename class/for to className/htmlFor, close void tags, and convert inline styles toward object form. Conversion stays local.

Estimate the probability of at least one collision for a given hash bit length and sample size using the birthday-paradox approximation. Useful for short IDs and truncated checksums. Calculation stays in the browser.

Parse PEM X.509 certificates locally to read validity, subject-related fields, and DER size. Lightweight inspection without full chain trust validation.

Decode JWT structure into formatted Header and Payload JSON with algorithm and expiry hints. Does not verify signatures; all processing stays local.

Identify UUID version and variant, validate 32-hex structure, and extract embedded timestamps for V1, V6, and V7—all locally in the browser.

Test JavaScript regular expressions in your browser with native RegExp. Supports flags such as i, g, and m, highlights matches, and shows capture groups with offsets for debugging email, crawler, and validation rules.

Locate invalid JSON error positions in your browser, highlight the character that triggers SyntaxError, and apply heuristic fixes for trailing commas, single quotes, and unquoted keys.

Generate QR codes locally in your browser with Canvas. Supports L through H error correction for URLs, text, WiFi payloads, and PNG download without uploading content.

Crop portrait photos to common ID, passport, and visa sizes in your browser. Switch red, blue, white, or gray backgrounds and pan/zoom—useful when starting from a transparent or white-backdrop bust shot.

Edit images in the browser: crop, rotate, color adjust, filters, AI cutout, annotations, mosaic, and SVG editing. Export PNG, JPEG, WebP, or SVG—files never leave your device.

Load a model and run inference locally to separate the subject into a transparent PNG. The first run downloads and caches weights; later runs can reuse the cache offline. Suited to product shots and portraits.

Strip EXIF/XMP and related metadata segments from JPG in your browser—GPS, camera, and author fields—while avoiding Canvas re-encode when possible so pixels stay intact. Useful before sharing photos.

Generate Nginx server blocks from form options, including reverse proxy, WebSocket, SSL, Gzip, and basic security headers. Copy or download conf files for static sites and app reverse-proxy starters.

Generate Dockerfiles for Node, Python, Go, and related stacks with optional multi-stage builds, non-root users, timezone packages, and a matching .dockerignore starter.

Select App, Nginx, database, and cache services to generate a local docker-compose.yml with ports and common dependency combinations for dev or demo environments.

Infer a Zod schema from sample JSON in your browser and emit TypeScript validation code. Nested objects and arrays are supported, with optional strict mode and z.infer type export—useful for API validation work.

Convert between Java Properties and YAML in your browser. Expand dotted keys such as spring.jpa.x=1 into nested YAML, or flatten YAML back to properties—useful for Spring config migrations.

Embed text into image pixels with LSB steganography and export PNG, or extract hidden text from a stego image. Differences are usually not obvious visually. Processing stays in the browser—suited to learning LSB basics and lightweight invisible marks, not strong cryptographic secrecy.

Test camera and microphone capture, local loopback, manual P2P signaling, ICE state, and real-time WebRTC statistics in your browser.

Encrypt and decrypt locally in your browser with AES, DES, 3DES, Rabbit, multiple block modes, direct keys, PBKDF2, or passphrase modes, outputting Base64 or Hex. Useful for API debugging and learning.

Enter pre-tax monthly salary to estimate pension, medical, unemployment, work-injury, maternity, housing fund deductions, and individual income tax. Includes city presets, housing-fund rates, and special additional deductions, plus take-home pay, yearly totals, and employer cost.

Generate RSA keys, a self-signed CA, server/client certificates, and CSRs locally, and parse PEM. Useful for local HTTPS without installing OpenSSL.