API workspace · schema & SQL visualizers · system design

See your APIs, data, and systems clearly

Interactive tools for building requests, visualizing schemas and SQL joins, and simulating system architecture — 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

Understand your APIs, data, and systems

The interactive tools we actively build and maintain — request building, schema and query visualization, and system design. Fast, private, and free. Looking for a quick utility instead? Browse the full library.

API Response Visualizer

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

Developer

GeoJSON & Map Data Visualizer

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

Developer

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.

Developer

API Flow Studio

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

Developer

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.

Developer

Big O Cheat Sheet

A filterable reference for data structure operations and sorting algorithm complexity — best, average, worst case, and space, at a glance.

Developer

Database Query Visualizer

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

Developer

Data Flow Visualizer

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

Developer

System Design Simulator

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

Developer

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.

Developer

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.

Utility

Next.js SEO & Performance Analyzer

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

SEO

Interactive DOM Inspector

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

Developer

HTML Fix Generator & Optimizer

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

SEO

Built for the modern web

TinkerTools is a fast, privacy-first toolbox for builders — essential utilities without the bloat.

Instant

Low latency. Heavy work stays in your browser whenever possible.

Private

Your content stays on your device — no accounts required.

Global

Built for developers and creators everywhere.

Polished

UI that stays out of your way so you can ship faster.

Ready to start tinkering?

Explore the full library — all tools are free and run in your browser.

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