UD5 Toolkit
Markdown to Rich Text - Online Copy for Google Docs
Convert Markdown to styled HTML that retains formatting when pasted into Google Docs or Word. Headings, bold, lists. Client‑side.
Markdown Linter - Online Check Syntax & Style
Markdown Linter
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Frequently Asked Questions
A Markdown linter analyzes your Markdown files for syntax errors, style inconsistencies, and formatting problems. It helps maintain readability, ensures compatibility across different Markdown renderers, and enforces team style guides automatically.
Common errors include: missing space after heading #, inconsistent list markers, unclosed code blocks, broken links or missing reference definitions, missing blank lines before/after headings or lists, and duplicate top-level headings.
It runs directly in your browser using JavaScript. No data is uploaded to any server. Your Markdown is parsed and checked against a set of customizable rules, and issues are displayed in real-time with line numbers and descriptions.
This tool focuses on detection. For automatic fixing, you can use tools like
markdownlint-cli --fix or editor plugins that support quick fixes. Our report helps you locate and manually correct problems.We enforce a subset of the popular markdownlint rules, including heading style, list spacing, code block closure, link validation, and blank line requirements. These align with the CommonMark and widely accepted best practices.
Pro tip: Integrate linting into your CI/CD pipeline with
markdownlint or remark-lint to enforce consistent Markdown quality across your team.
Canonical Tag Checker - Online Rel=Canonical Inspector
Check a live URL to extract and validate its canonical link element. Ensure correct SEO configuration. Runs from your browser.
Canonical Tag Inspector - Online Check Rel=Canonical from Page Source
Paste HTML or URL to extract canonical link tag. Verify self-referencing. Simple SEO audit step. Local only.
Proofreading Marks Reference - Online Editors' Cheat Sheet
A visual guide to common copy‑editing and proofreading symbols. Click a mark to see its meaning. For writers.
Markdown Link Rewriter - Online Relativize or Absolutify URLs
Paste Markdown and convert all links from absolute to relative (or vice‑versa) based on a base domain. Bulk edit.
Highlighted Text Extractor – Online Gather Citations From Web
Paste text with highlights (e.g., from Apple Books) and extract only the highlighted lines. Save as list.
Rendering Intent Hint Demo - Online content‑type CSS
Test how `content‑type: text/html` vs `content‑type: image/svg+xml` affects SVG rendering in the browser. Modern performance hint.
SEO Friendly URL Rewriter - Online Slug Optimizer
Convert messy URLs into clean, keyword-rich slugs. Remove stop words, replace spaces with hyphens. Lowercase transformation. All local.
Permissions Query API Demo - Online Check All APIs
Query the permission state of camera, microphone, geolocation, and more. See the response and learn the API.
Mock Sentence Generator - Online SaRcAsM wRiTiNg
Turn any sentence into mocking SpongeBob‑style text. Choose intensity. Copy and paste into chats. Pure client.
FormData to JSON Converter - Online Debug Multipart
Fill in a form and see the FormData object as JSON. Perfect for debugging multipart form submissions. Client-side.
Sunrise Sunset Times - Online Any Location
Enter a city name or coordinates and see today's sunrise, sunset, and twilight times. Approximate algorithm. Local.
VIA Character Strengths Generator - Online Positive Psychology
Take a lighthearted inventory of your character strengths (not official VIA). Self-reflection tool. All in browser.
Contact Picker API Demo - Online Select & Read Contacts
Pick a contact from the device’s address book (mobile). Read name, email, and phone. All permission‑based. Privacy safe.
User Idle Time Display - Online See Seconds Since Activity
Shows a counter of how many seconds you have been idle. Tracks mouse and keyboard activity without recording.
Ideal Weight Chart - Online BMI & Health Range Guide
See the healthy weight range for your height using standard BMI chart. Gender‑specific data. Quick reference.
UPC Barcode Validator - Online Check Digit & EAN
Enter a UPC or EAN barcode number and validate the check digit. See if it's a real product code. Local calculation.
CSS Compatibility Linter - Online Check Browser Support
Paste your CSS and see warnings for properties that have limited browser support. Links to CanIUse. Modernize safely.
Markdown to Email HTML - Online Newsletter Template
Write in Markdown and get clean, inline‑styled HTML suitable for emails. Pre‑designed templates included. Local conversion.
ARIA Attribute Validator - Online Check HTML Accessibility
Paste an HTML snippet and check for common ARIA mistakes: missing labels, invalid roles, and aria‑hidden misuse. Educate your team.
Markdown to Slack mrkdwn Converter - Online
Convert standard Markdown into Slack’s mrkdwn format. Fixes bold, italic, and lists for perfect Slack message formatting.
SQL Syntax Validator - Online Quick Check
Paste your SQL query and check for basic syntax errors. Highlights missing commas, wrong keywords. Local analysis.
Crypto Address Format Checker - Online Validate Wallet
Paste a Bitcoin, Ethereum, or other crypto wallet address and quickly verify its format and checksum. No connection to blockchain.
Markdown TOC Generator - Online Table of Contents
Paste your Markdown and automatically generate a linked table of contents based on headings. Insert at the top. Local magic.
Code Syntax Highlighter - Online Beautiful Code Preview
Paste code and get a beautifully highlighted preview with line numbers. Supports many languages. Copy as HTML. Pure frontend.
Markdown Footnote Generator - Online Add Auto‑numbered Notes
Write text with inline footnote markers and this tool will move the notes to the bottom and add proper Markdown links. Saves time.
TOML Formatter & Validator - Online Config Tool
Check and beautify your TOML config files. Highlights errors and aligns tables and arrays. Safe local parsing.
YAML Validator & Formatter - Online Check Syntax
Validate YAML syntax with line‑by‑line error messages. Also format messy YAML into clean, indented output. All in your browser.
ISBN Validator - Online Check ISBN‑10 & ISBN‑13
Validate ISBN‑10 and ISBN‑13 numbers and compute their check digits. Useful for booksellers and libraries. All local.
.htaccess Validator - Online Check Syntax
Paste your .htaccess rules and check for common syntax errors or misconfigurations. No server required; static analysis.