System Design Tool
Draw HLD, LLD, and infrastructure diagrams with cost estimation. Free, no signup.
Auto-saves to browser. Powered by Excalidraw (MIT).
How the System Design Tool Works
Toolkiya's system design tool is an interactive learning and interview-prep environment for understanding distributed system architectures. It presents common system design scenarios (URL shortener, Twitter feed, Uber, YouTube, WhatsApp, TinyURL, Instagram, Netflix) with interactive diagrams showing the high-level components, data flows, and scaling bottlenecks for each.
Each scenario walks you through capacity estimation (QPS, storage, bandwidth), API design, high-level architecture (load balancer, app servers, caching layer, database, CDN), detailed component design (sharding strategy, replication, consistency model), and identification of bottlenecks. The tool is designed for software engineers preparing for FAANG-level system design interviews or anyone building scalable web services.
When to Use System Design Practice
Preparing for senior software engineer interviews at Google, Meta, Amazon, Microsoft, Uber, LinkedIn, Netflix, or any company that asks system design questions. Refreshing distributed systems concepts before an internal architecture review. Understanding real-world architectures by studying well-known systems. Teaching junior engineers how to decompose a product into scalable components.
Engineering managers use it to structure design doc templates for their teams. Tech leads use it as a reference during architecture decision records (ADRs). Bootcamp students use it to close the gap between coding interviews and real production systems.
Why Learn System Design Here
Most system design resources are either 40-hour paid courses (Educative, DesignGurus) or scattered YouTube videos of variable quality. Toolkiya's tool gives you a concise, interactive walkthrough of canonical system designs — free, no signup, no paywalls.
The interactive diagrams let you click each component to see its purpose, alternative choices, and failure modes. The capacity-estimation sections include realistic back-of-envelope math showing how to derive numbers interviewers expect. Updated for 2026 with modern stacks (Kubernetes, Redis, Kafka, Cassandra/DynamoDB, CDN-as-compute).
Frequently Asked Questions
What is this System Design Tool?▼
A free online whiteboard for drawing High-Level Design (HLD), Low-Level Design (LLD), and cloud infrastructure diagrams with pre-built templates and cost estimation.
Can I save my diagrams?▼
Yes. Diagrams auto-save to your browser every few seconds. You can also export as PNG to share with your team.
How does cost estimation work?▼
Add infrastructure components, choose your cloud provider (AWS/GCP/Azure), adjust quantities, and see real-time monthly cost estimates.
Is this tool free?▼
Yes, 100% free. No signup, no watermarks, no limits. Everything runs in your browser.
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Built & maintained by Mayank Rai
Solo developer based in Lucknow, India