Using the System Design Studio

The System Design Studio is the visual practice surface. Instead of implementing a method, you place provider-neutral components on a canvas, connect them, and ask the grader whether the topology satisfies the challenge's authored rules. This guide covers the workspace itself. For what each series teaches, see the public System Design Studio overview.

Open the Studio

Choose System Design Studio in the app navigation when it is available for your account. It opens the first challenge in curriculum order that you can access and have not solved, so returning learners land on their next step. Design challenges do not appear in the ordinary puzzle list; the Studio has its own catalog.

On wide screens a Challenges rail on the left lists every series with its solved count and can be collapsed. On narrower screens the same catalog opens from the Challenges button. Series run from the reusable Fundamentals through product builds (video platform, URL shortener, file vault, notification platform, real-time chat, reliable checkout, social feed, distributed web crawler, verifiable release pipeline) and an optional capstone. Each course advances from Easy through Medium to Hard.

All puzzles takes you back to the code Playground.

Read the brief

The brief states a requirement, the pattern that answers it, and a list of goals. The goals are the rules the grader will check, written in plain language, so read them as the specification. Some briefs say "rebuild" the machinery from an earlier stage; the starter for a Hard challenge deliberately pre-places little more than the entry point.

Hide brief gives the canvas the full width when you know what you are building. After a passing Submit, a Lesson tab appears beside the brief with the "why this works" explanation: the idea to keep, the statelessness or idempotency requirement it implies, where the design can still fail, and what changes at real scale.

Build on the canvas

The palette above the canvas lists only the components that express real choices for this challenge. Click a component to place it at the next open spot, or drag it to an exact position.

• Connect by dragging from a component's right handle to another component's left handle. A connection the challenge does not allow snaps back; the Inspector explains what each component may connect to.
• Remove a connection by double-clicking it. Remove a component with Backspace or Delete while it is selected, which also removes its connections.
• Boundaries such as a virtual network or subnet are resizable regions. A component dragged inside becomes part of that boundary and moves with it; dragging it out releases it. Containment is graded, so a box drawn behind a service without adopting it does not satisfy a security rule.
• Tidy auto-arranges the design left to right. Dragging the midpoint of a connection bends it for readability and does not affect the grade.

Each challenge sets a component and connection budget. The counters (Components n/max, Connections n/max) stay visible, and the canvas refuses additions beyond the limit. The connection kinds in your design are inferred from their endpoints and listed in a legend: Request, Async work, Signed upload, Object read, Secrets / control, Telemetry, and Replication. Each kind has its own color, so a worker reading from object storage looks different from an app service calling an API.

Inspect a component

Selecting a component opens the Inspector: what the component is for, which components this challenge allows it to connect to and receive connections from, and any configuration it carries, such as a capacity tier. Allowed does not mean required. The challenge grades which connections are right, not how many of the permitted ones you drew. Configuration values are clamped to the challenge's range and feed the capacity report below.

Check, then Submit

Check grades the current topology against the rules and the public traffic scenario without marking the challenge solved. Use it as often as you like while iterating. Submit grades the same rules plus the server-only hidden scenarios and records the solve. Both trace an illustrative packet along the client's path so you can see direction and reachability; the animation is skipped when your system prefers reduced motion. Any edit after a result invalidates it, so Check again before you Submit.

The Validation panel starts as a slim rail and expands on the first result. Rules are grouped by category, in this order: Correctness, Security, Reliability, Performance, Observability, each with a passed count. Failed rules come first with a detail naming the property to fix; passing rules fold into a Passed checks disclosure. After a passing Submit, the panel offers Next and Read the lesson.

The capacity report

Once every structural rule holds, a deterministic capacity simulation runs your design under the challenge's modeled traffic and reports:

• p99 latency, throughput, error rate, and modeled monthly cost for the design as a whole;
• a bottleneck callout naming the component that saturated first and why, with the same component flagged on the canvas;
• one row per quantitative goal with the target, your value, and how far over or short it is;
• a throughput-over-time chart and a breakdown per traffic condition. Submit evaluates hidden traffic conditions that Check does not.

The result summary states whether the structure and the quantitative goals passed. The report is a reproducible model built for learning: the same design under the same scenario always produces the same numbers, which makes it useful for comparing two of your own designs. It is not a provisioned load test, and passing it does not prove a production system would hold.

Reveal, reset, and drafts

Reveal design loads a passing reference topology onto the canvas after a confirmation. It is a study tool: later passes on that challenge still count as completion, but they are marked as revealed, earn reduced rewards, and do not take a clean ranking. Study the reference, then Reset and rebuild it yourself.

Reset returns the canvas to the starter topology. Your work-in-progress canvas, including positions, is saved automatically after a short pause per challenge, and for signed-in learners it syncs across devices as a draft.

Free and Pro

Six challenges are free, including three Fundamentals previews and a complete Easy, Medium, Hard mini-course. Anyone can build and edit in the Studio without an account; Check and Submit ask you to create a free account first, and your in-browser draft is kept while you do. A locked challenge shows its title, difficulty, and summary with an upgrade action; the rest of the curriculum is on Pro, along with the System Design Foundations learning path that orders the fundamentals and video-platform challenges into a 12-step route.

On a phone

The Studio works on small screens with one-time hints that explain the layout, but a canvas with twenty components and their connections is easier to reason about on a desktop. The tracks guide explains how the Studio sits beside the code tracks, and How grading works covers the shared result statuses.