Developer Tools

Estimate what an LLM-powered feature will cost — tokens per request, requests per month, input/output prices per million tokens, prompt caching and batch discounts. Works for any model: enter your provider's current prices.

Format and beautify SQL queries for PostgreSQL, MySQL, SQL Server, SQLite, BigQuery and more, with uppercase keywords.

Beautify messy or minified HTML, CSS and JavaScript into clean, consistently indented code you can read and edit.

Convert Markdown to clean HTML — headings, lists, links, tables, code blocks and GitHub-flavored Markdown supported.

Convert HTML into clean Markdown for READMEs, docs and static sites — headings, links, lists, tables and code preserved.

Minify CSS or HTML to shrink file size — strips comments and whitespace and shows how many bytes you saved.

Convert numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36 — including very large integers.

Format, beautify, validate and minify JSON — with clear line and column error messages and optional key sorting.

Convert YAML to JSON and JSON to YAML for Kubernetes, Docker Compose, GitHub Actions and other config files.

Pretty-print and validate XML with readable indentation, or minify it — errors point to the exact line and column.

Convert XML to JSON and JSON back to XML, keeping attributes (as @name) and repeated elements (as arrays).

Convert CSV or spreadsheet data to a JSON array of objects, with header detection, number/boolean typing and any delimiter.

Turn a JSON array of objects into CSV for Excel or Google Sheets — nested objects are flattened into dot-notation columns.

Generate SQL CREATE TABLE and INSERT statements from CSV data for MySQL, PostgreSQL, SQLite or SQL Server.

Convert config files between TOML, INI, .env and JSON — validate a TOML file or turn a .env into JSON in one step.

Generate TypeScript interfaces or Go structs from sample JSON — nested objects, arrays and optional fields inferred automatically.

Compare two JSON documents semantically — see added, removed and changed values by path, ignoring key order and formatting.

Query JSON with JSONPath expressions like $.store.book[*].author or $..price and see every match with its exact path.

Generate a JSON Schema (draft 2020-12) from sample JSON — types, nested objects, arrays, required fields and formats like email, date-time and URI.

Generate a production-ready Dockerfile and docker-compose.yml for Node.js, Python or static sites — with PostgreSQL, MySQL, Redis or MongoDB services.

Generate an nginx server block for a static site, SPA or reverse proxy — with HTTPS (Let's Encrypt paths), HTTP→HTTPS and www redirects, gzip and caching.

Paste raw email headers to trace the route, see delays between servers, and check SPF, DKIM and DMARC results — useful for spotting spoofed or phishing emails.

Check HTML for unclosed or mismatched tags, duplicate IDs, images without alt text, missing lang/title/viewport and other common mistakes.

Convert plain CSS declarations or rules into Tailwind CSS utility classes — spacing, flexbox, grid, typography, colors, borders and more, with arbitrary values where needed.

Encode text to Base64 or decode Base64 back to text, with full UTF-8 support and a URL-safe option.

Percent-encode text for URLs and query strings, or decode %20-style encoded URLs back into readable text.

Escape <, >, & and quotes as HTML entities, or decode named and numeric entities (&amp;, &#169;, &#x1F600;) back to text.

Escape or unescape strings for JavaScript, JSON, HTML, XML, SQL, CSV and regular expressions — quotes, backslashes and newlines handled.

Convert text to binary, hexadecimal, octal or decimal byte codes (UTF-8), and convert those codes back to text.

Generate MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512 and CRC32 checksums of any text, instantly and privately in your browser.

Create HMAC signatures with SHA-256, SHA-512, SHA-1 or MD5 from a message and secret key, as hex or Base64 — for webhooks and API signing.

Decode a JSON Web Token to read its header and payload, check expiry times, and verify HS256/384/512 signatures with your secret.

Minify JavaScript with Terser — removes whitespace and comments, shortens variable names and drops dead code to cut file size.

Look up every HTTP status code — 200, 301, 404, 429, 502 and more — with what it means and when servers send it.

Full ASCII table with decimal, hex, octal and binary codes for all 128 characters, control code names and HTML entities.

Time and space complexity of common data structures and sorting algorithms — average and worst cases in Big-O notation.

The Git commands you actually need — setup, branching, undoing mistakes, stashing, rebasing and working with remotes — with what each does.

Build a .gitignore file for your stack — Node, Python, Java, Go, Rust, .NET, Flutter plus OS and editor files — in a few clicks.

Generate Apache .htaccess 301 and 302 redirect rules from a list of old and new URLs, plus force-HTTPS and www rules.

Generate a modern HTML5 starter page with the viewport meta tag, SEO description, Open Graph tags, favicon and stylesheet links.

Paste a regular expression and get a plain-English, token-by-token explanation — character classes, groups, lookarounds, quantifiers, anchors and flags. Works with JavaScript and PCRE-style syntax. No AI, instant.

Validate Kubernetes manifests in your browser — YAML syntax, required fields, current apiVersions, selector/label mismatches, image tags, resource limits, probes and security settings.

Translate SQL into MongoDB queries — SELECT with WHERE (AND/OR, IN, LIKE, BETWEEN, IS NULL), ORDER BY, LIMIT, GROUP BY aggregations, plus INSERT, UPDATE and DELETE.

Shrink SVG files by removing editor metadata (Inkscape, Illustrator, Sketch), comments and whitespace, and rounding long decimals — with the size saving shown. Paste the SVG code.

Paste an Excel or Google Sheets formula and get a plain-English, step-by-step breakdown of every function, reference and operator — including nested IFs, lookups and ranges.

Convert Unix epoch timestamps (seconds, milliseconds, microseconds) to readable dates in any time zone — and dates back to timestamps.

Translate cron expressions into plain English and list the next run times — supports ranges, steps, names and @daily-style macros.

Convert Linux file permissions between numeric (755) and symbolic (rwxr-xr-x) notation, with a plain-English breakdown and the chmod command.

Calculate network address, broadcast, subnet mask, wildcard, usable host range and host count for any IPv4 address and CIDR prefix.

Compare two semantic versions, check whether a version satisfies an npm range like ^1.2.0 or ~2.3, and see the next major, minor and patch versions.

Test JavaScript regular expressions live — see every match highlighted, capture groups, named groups and match positions.

Convert cURL commands into JavaScript fetch, Python requests or Go net/http code — headers, JSON bodies, auth and methods included.

Send HTTP requests from your browser — any method, query params, headers, JSON or form body, bearer/basic/API-key auth — and inspect status, timing, headers and pretty-printed JSON. Export as cURL, JavaScript or Python.

Design CSS box shadows, rounded corners and frosted-glass (glassmorphism) effects with sliders and a live preview — then copy the CSS.

See your browser, version, operating system, user agent, screen resolution, viewport size, pixel ratio, language, time zone and supported features — handy for bug reports.

Create CSS clip-path shapes visually — triangles, hexagons, stars, arrows, speech bubbles and more — drag points to customize and copy the polygon() CSS.

Turn code snippets into beautiful images for Twitter, LinkedIn, slides and docs — syntax highlighting, themes, window chrome and gradient backgrounds. Download PNG or copy to clipboard.

Pick a color or paste any code and convert between HEX, RGB, HSL, HSV and CMYK — with tints, shades and ready-to-copy CSS values.

Generate harmonious color palettes — complementary, analogous, triadic, split-complementary and monochrome — from any base color, with CSS variables to copy.

Check text and background colors against WCAG 2.2 AA and AAA contrast requirements — with a live preview and a suggested fix when a pair fails.

Test whether an API allows cross-origin requests from the browser — any method, headers and credentials. See if a preflight was needed, what failed, and get the server config to fix it.

Create CSS keyframe animations visually — fade, slide, bounce, pulse, shake, spin and more — tune duration, easing, delay and repeat with a live preview, then copy the CSS.

Build linear, radial and conic CSS gradients visually — add color stops, set the angle and copy the CSS (or Tailwind class) with a live preview.

Validate CSS against the specifications — syntax errors, unknown properties, invalid values, duplicates, unclosed blocks — and add vendor prefixes for your target browsers with Autoprefixer.

Look up DNS records for any domain — A, AAAA, CNAME, MX, TXT (SPF/DKIM/DMARC), NS, SOA, CAA, SRV and reverse PTR — compared across Google and Cloudflare to spot propagation issues.

Build flexbox and CSS grid layouts visually — direction, wrap, alignment, gap, columns and rows — and copy the CSS or Tailwind classes.

Write HTML, CSS and JavaScript and see the result instantly — live preview, console, templates, shareable links and one-click HTML download. Like CodePen, with nothing to sign up for.

Test your internet speed — download, upload, ping and jitter — in about 15 seconds, with a plain-English verdict on what your connection can handle.

Find the approximate location, internet provider, organization and ASN of any IP address or domain — IPv4 and IPv6.

Run JavaScript or TypeScript in your browser with a real console — console.log, console.table, async/await, fetch and timers. Stop runaway loops, and share snippets as a link.

Find the manufacturer of any MAC address from the official IEEE registry — paste one or hundreds, in any format — and spot randomized private addresses.

Create a mock REST endpoint in seconds — pick the status code, JSON/XML/text body, custom headers and delay — and call it from your app with CORS enabled.

Write and run Python 3 in your browser — no install, no account. Real CPython (Pyodide) with input(), NumPy, pandas and Matplotlib charts, and shareable links.

Practice and run SQL in your browser on a real SQLite database — sample shop data included, joins, CTEs and window functions, import CSV/Excel as tables, open .db files and export results.

Extract data from any web page without coding — tables, links, headings, images, meta tags or anything matching a CSS selector — and export to CSV, Excel or JSON.

Get a unique URL that captures every HTTP request sent to it — method, path, query, headers and body — to debug webhooks from Stripe, GitHub, Shopify, Zapier and more.

See your public IPv4 and IPv6 address, approximate location, internet provider and what else websites can see about your connection — instantly.