Robots.txt Generator - Online Create & Validate Robots File
Build a properly formatted robots.txt file with user-agent rules and sitemap location. Validate syntax in real time. Essential for webmasters.
UD5 Toolkit
Quickly scaffold a LitElement web component with properties, styles, and events — ready to code.
user-card, data-table
npm install lit. Then import the necessary modules like LitElement, html, and css from the lit package. The generated code already includes the correct import statements.
properties is a getter that returns an object describing each reactive property. For each property you can specify its type (how to convert from HTML attribute), reflect (whether to sync back to the attribute), and other options. This mechanism replaces the older decorators approach and works natively in JavaScript.
styles property where you can define scoped CSS using the css tagged template literal. Styles defined here only affect your component's shadow DOM. If you check "Include static styles" in the generator, a basic :host block is added, which you can expand later.
this.dispatchEvent(new CustomEvent(...)). The generator can include a sample event method that shows how to fire an event with detail and bubbling options. You can trigger this method from your template or lifecycle callbacks.
@customElement and @property decorators, along with proper type annotations. This approach is widely used in modern Lit projects and provides excellent IDE support.
reflect: true is set, changes to the property in JavaScript will automatically update the corresponding HTML attribute on the element. This is useful when you want CSS attribute selectors or debugging tools to see the current state reflected in the DOM.
connectedCallback, disconnectedCallback, attributeChangedCallback, and additional Lit-specific ones like firstUpdated and updated. Override them in your class. The generated skeleton doesn't include them by default, but you can easily add them after generation.
Build a properly formatted robots.txt file with user-agent rules and sitemap location. Validate syntax in real time. Essential for webmasters.
Create a reflection effect for images or text using box‑reflect. Adjust direction and offset. Copy the CSS.
Create a custom element with named slots and see content projection in action. Learn Web Components basics.
Fill in your details and generate a professional-looking invoice ready to print or save as PDF. No sign-up, all data stays on your device. Great for freelancers.
Fill in your details and generate a professional‑looking invoice ready to print or save as PDF. No sign‑up, all data stays on your device.
Adjust opacity visually with a slider and see the different CSS representations (opacity property vs RGBA/HSLA). Copy best option.
Select any HTML element on a page and capture its screenshot. Download as PNG. Perfect for bug reports. JavaScript API demo.
Turn your browser screen into a full‑color flashlight or strobe. Adjust brightness and color. Simple utility.
Convert REM values to pixels and vice versa based on your root font size. Essential for scalable web typography.
Paste HTML and see a before/after comparison of minified output. Check the byte savings. All local.
Fill in title, date, time, and location to generate a downloadable .ics meeting invitation. Works with all major calendars.
Assign Secret Santa pairings from a list of names with spouse/partner exclusions. Optionally email results via mailto link. Fully local, no server.
Generate a realistic, random user‑agent string for desktop, mobile, or bot. Perfect for API testing and scraping.
Paste your own text and generate a random sentence that mimics its style. Use for creative writing prompts or testing. Fully local.
Set watering schedules for multiple plants with visual alerts. Shows which plants need water today based on last watered date. Data stored locally.
Enter a URL and generate a responsive iframe embed code with correct aspect ratio. Supports YouTube, maps, and more.
Count total DOM nodes on the current page and show warnings if limits exceed best practices. Keep the DOM lean.
Play a metronome with adjustable BPM, time signature, and subdivisions (eighth, triplet, sixteenth). Tap tempo and visual flash. Works offline for practice.
Paste a robots.txt file and validate its syntax. See if a specific user‑agent can access a path. Essential for webmasters.
Register a service worker, subscribe to push, and send a test notification using a VAPID key pair. Step‑by‑step demo.
Convert pixel values to em and rem units based on a base font size. Bidirectional. Must‑have for front‑end developers.
Change the text input cursor color. See the effect live. Copy the minimal CSS. Simple but delightful.
Paste robots.txt content and parse it to check validity, find disallowed paths. Educational SEO tool. Local processing.
Spin a colorful wheel that lands on Yes, No, or custom answers. Includes sound effects and adjustable probability. Local fun decision maker.
Generate CUIDs that are optimized for horizontal scaling and collision resistance. Great for client‑side IDs. Pure JavaScript.
Click for a warm, encouraging sentence to lift your spirits or support a friend. Small positive boost. No repeats.
Find the centroid (center of mass) of any convex polygon by entering vertex coordinates. Useful for physics and design.
Paste a user agent string to get a human-readable breakdown of browser, operating system, and device. See your own current agent info automatically.
Click any element on a demo page and see which events are attached. Visual debugger for event handling.
Create a random, aspirational quarterly objective with unrealistic key results. For meeting icebreakers.