How system design rounds are scored
Interviewers grade the process more than the final diagram. Most rubrics look for the same six signals:
| Signal | What good looks like |
|---|---|
| Requirements | Clarifying questions first; functional and non-functional needs separated |
| Estimation | Traffic, storage and bandwidth sized, with the assumptions said out loud |
| High-level design | Clear components, an API and a data flow the interviewer can follow |
| Deep dive | One or two components in detail: storage choice, caching, partitioning |
| Trade-offs | Alternatives named, and a reason one wins for this problem |
| Communication | You drive the conversation and check in with the interviewer |
A plan for 45 minutes
| Minutes | Phase | What you produce |
|---|---|---|
| 0 to 5 | Clarify | Users, core features, scale, latency and consistency needs |
| 5 to 10 | Estimate | Requests per second, storage per year, read to write ratio |
| 10 to 20 | High-level design | API, data model, main components and how data moves |
| 20 to 35 | Deep dive | The hardest one or two components, in detail |
| 35 to 45 | Wrap up | Bottlenecks, failure modes, how it scales, what you would do next |
Where Solvro helps
The prompt. In Interview mode, Solvro hears "design a URL shortener" and returns an outline within seconds: the clarifying questions worth asking, an estimate with its assumptions, the main components, a data model and the trade-offs to raise. You lead the conversation; the outline keeps you from skipping a step.
Follow-ups. The conversation keeps context, so "how would you handle a hot key?" or "what if reads grow ten times?" is answered for the design you have been describing, not a generic one. Press CtrlShiftN when the interviewer moves to a new question.
Diagrams and documents on screen. If the interviewer shares a diagram or a requirements document, capture it with CtrlShiftS and ask in Query mode, for example "where is the bottleneck in this design?".
Models. System design rewards reasoning more than speed. Claude Opus 5 and Claude Fable 5 go deepest; the Gemini models are fastest. Switch with CtrlShiftM.
Your own systems. Interviewers often ask about systems you have built. With your resume in Settings, answers can point to your real projects instead of textbook examples.
Numbers worth having ready
Estimates do not need to be exact, only reasonable and stated. These conversions cover most of them:
| Fact | Rough value |
|---|---|
| Seconds in a day | 86,400, about 100,000 |
| 1 million requests a day | About 12 requests a second |
| 100 million requests a day | About 1,200 requests a second |
| 1 KB for each of 1 million items | About 1 GB |
| 1 MB for each of 1 million items | About 1 TB |
| Reading from memory | About 100 nanoseconds |
| Round trip inside a data centre | About 0.5 milliseconds |
| Round trip between continents | About 150 milliseconds |
What an assistant can't do for you
- Draw the diagram. Solvro returns text: components, data flow and trade-offs. You sketch from the outline.
- Own the trade-off. Interviewers push back on purpose. Defending a choice has to come from you.
- Invent experience. Deep-dive questions probe what you have actually built. Keep answers tied to your real projects.
Check the rules first
Most employers and assessment platforms prohibit outside help in their terms. Solvro keeps its window out of screen captures, but no tool can promise it will never be noticed, and breaking those rules can cost you an offer. Decide for yourself whether that risk is worth taking.
Frequently asked questions
Yes, mainly with structure and recall. Solvro's Interview mode hears the prompt and returns an outline in seconds: clarifying questions, an estimate, components, a data model and trade-offs. You still lead the conversation and draw the design.
The deeper reasoning models, Claude Opus 5 and Claude Fable 5, suit open-ended design questions. The Gemini models are faster when you need a quick answer. Switch with Ctrl Shift M.
No. It returns text: the components, how data flows between them and the trade-offs. You sketch the diagram from that outline.
Usually 45 to 60 minutes: about five minutes on requirements, five on estimates, ten on the high-level design, fifteen on a deep dive and the rest on trade-offs and scaling.
Spoken questions use Interview mode, included in Pro+ from $49 a month and in the $24 Sprint Pass. Query mode, for diagrams and documents on screen, is in every paid plan.