Developer utilities · SEO · everyday tools

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JSON, schemas, HTML quality, and productivity helpers — all run in your browser with no accounts and no data leaving your device.

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HTML tooling

Automatically fix & optimize your HTML

Fetch a URL or paste raw markup, then get an optimized document with SEO metadata, lazy-loaded images, and accessibility names — before/after diff included.

✓ Auto-fix missing meta description, H1 structure, and image alt text
✓ Performance hints: lazy images, leaner inline styles
✓ Side-by-side diff with categorized fix explanations

Open HTML Fix Generator

Developer utility

Visualize & optimize your DOM structure

Explore an interactive tree with depth cues, click any node for attributes and insights, and review SEO, accessibility, and performance hints — like a focused Elements panel.

Open DOM Inspector

Popular tools

Every utility in one place — fast, private, and free. Open any tool in full screen when you need focus.

JSON Formatter & Validator

Format, validate, and beautify your JSON data instantly.

API Response Visualizer

Paste JSON from APIs: collapsible tree view, TypeScript interfaces, and optional Zod schema generation.

GeoJSON & Map Data Visualizer

Paste GeoJSON and explore it on an OSM basemap: points, lines, polygons, feature inspection, fit bounds, and export.

API Request Builder & Code Generator

Build HTTP requests with URL, method, headers, query, and JSON body — copy ready-to-run fetch, Axios, or cURL snippets.

API Flow Studio

Visual API workspace: send requests, lifecycle flow animation, timing waterfall, JSON explorer, JWT auth, OpenAPI import, mocks, and multi-language codegen.

Time Complexity Visualizer

Compare Big O growth: O(1), O(log n), O(n), O(n log n), and O(n²) on interactive charts with plain-language explanations.

Database Query Visualizer

Paste SELECT SQL to see tables and joins as an interactive graph — INNER, LEFT, RIGHT, FULL, CROSS — plus a structured breakdown.

Data Flow Visualizer

Sketch pipelines from arrow text or JSON: interactive React Flow canvas, cycle & bottleneck hints, metadata per step, export JSON or PNG.

System Design Simulator

Build distributed architectures on a live canvas, simulate 1K–100K users, visualize bottlenecks, configure nodes, and learn with explain mode.

Universal Schema Visualizer

Paste Prisma schemas, SQL DDL, or MongoDB JSON — get an interactive ER diagram with relationships, export PNG or JSON, and share a link.

Base64 Encoder/Decoder

Encode and decode strings or files to/from Base64 format.

JWT Decoder

Decode and inspect JSON Web Tokens (JWT) without compromising security.

UUID Generator

Generate high-quality UUIDs (v1, v4) for your applications.

Regex Tester

Test and debug your regular expressions in real-time.

Password Generator

Create secure, random passwords with customizable parameters.

QR Code Generator

Generate custom QR codes for URLs, text, or contact info.

Word Counter

Count words, characters, and sentences in your text.

Text Case Converter

Convert text between UPPERCASE, lowercase, camelCase, snake_case, etc.

Slug Generator

Convert any string into a URL-friendly slug.

Pincode Radius & Coverage Finder

Map pincode coverage with a circle or custom polygon, see area in m² and sq ft, and list nearby pincodes — for logistics, delivery, and real-estate land sketches.

Next.js SEO & Performance Analyzer

Audit HTML for SEO, performance hints, and Next.js-specific optimizations — scores and actionable fixes.

Interactive DOM Inspector

Parse HTML into an interactive tree with depth cues, per-node inspection, and heuristic SEO, a11y, and performance insights.

HTML Fix Generator & Optimizer

Paste HTML or fetch a URL, then auto-fix SEO tags, lazy-loading, accessible names, and view a highlighted diff.

Meta Tag Generator

Generate SEO-optimized meta tags for your website.

Open Graph Preview

Preview how your website appears on social media platforms.

Age Calculator

Calculate your exact age in years, months, and days.

Percentage Calculator

Solve common percentage math problems quickly.

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