AI system design interview assistant

How Co-Help helps with system design interviews

Co-Help transcribes the system design discussion live, so it has context as requirements, scale numbers, and trade-offs come up. When you need to reason through an architecture out loud, Co-Help's AI (Anthropic Claude, with OpenAI GPT as automatic fallback) suggests components, trade-offs, or missing pieces. Co-Help can also render architecture and flow diagrams and read diagrams already on your screen through screenshot Q&A — useful when a whiteboard tool or shared doc shows a system you need to reason about quickly.

Built for the format

• Diagram rendering (Pro Max) — get an architecture or flow diagram sketched out based on the discussion.
• Screenshot Q&A on existing diagrams (Pro Max) — capture a whiteboard or doc and get an explanation of what's shown.
• Live transcription — keeps track of requirements and constraints as the interviewer states them.
• Consent: Some places require every participant's consent before a call is transcribed. You're responsible for getting it.
• Screen-capture protection — the overlay asks your OS to exclude it from capture, including when a whiteboard tool or diagram is the shared window (not guaranteed).
• Review before you rely on it: AI answers can be wrong or incomplete. Review every suggestion before you rely on it.

Pricing for every interview type

The same three plans cover every interview type — there's no separate add-on for coding, system design, or behavioral support:

• Free 15-minute trial — Pro Max features, no card needed. The clock starts at your first question.
• Pro — $10 per session, 5 for $39, $79 for 30 days or $349 a year: fast models, sessions up to 90 minutes, no screenshots or diagrams.
• Pro Max — $20 per session, 5 for $75, $150 for 30 days or $600 a year: the most advanced models, screenshots and diagrams, sessions up to 2 hours.

Every plan includes humanized answers from Anthropic Claude with OpenAI GPT as automatic fallback, live transcription, answers from your documents and knowledge base, GitHub-connected answers, 20+ languages, the phone companion and the private overlay with screen-capture protection — with no API keys to manage. Screenshot Q&A and diagram rendering are Pro Max features.

Works on the platform you're interviewing on

Co-Help runs as a desktop overlay, independent of whichever video call tool your interview uses. It uses the same OS-level screen-capture protection with Zoom, Microsoft Teams, and Google Meet alike, on both Windows and Mac.

Practice first, then live help where it's allowed

• Practice mode. Run a system design, coding or behavioral mock interview for the role and seniority you choose. Answer by typing, or out loud with a voice interviewer that reads each question and can ask a follow-up (voice practice is tailored to a job description you paste in). System design answers are scored on requirements and scope, high-level architecture, scalability and trade-offs, data model and storage, and reliability and operations. Each answer gets a 1–10 score, written feedback and a model answer, and you can download each report as a Markdown file. Practice is included with paid plans (unlimited on 30-day and yearly plans) and doesn't use up a live session. See AI mock interview practice.
• Live help, where it's allowed. In system design interviews that permit AI assistance, Co-Help transcribes the discussion, suggests components and trade-offs, and renders or explains diagrams on a private overlay.
• Check the rules. Many employers, schools and testing platforms don't allow AI help. You're responsible for following them. Read the acceptable-use terms and Is it OK to use AI in an interview?

GitHub-connected answers. Connect GitHub with a personal access token and Co-Help indexes your repositories, so when an interviewer asks about your own projects, technical answers are grounded in your actual code instead of a generic guess. After each call, your session report and history let you review the questions and answers.

Want the full picture of live help plus practice? See the AI interview copilot overview.

Other interview scenarios Co-Help covers

Frequently asked questions