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Interview Summary

The Tesla system design interview asked me to design the backend and supporting services for a Supercharger platform. The interviewer initially gave three major functional requirements: billing based on delivered energy, long-term charger health telemetry, and a map experience for finding nearby available Superchargers with pricing. In practice, most of the interview went deeply into the first requirement, especially networking, communication, buffering, and synchronization decisions.

Interview Details

System Design — Tesla Supercharger Platform Design a system supporting Tesla Supercharger stations with three major requirements.

• Requirement 1 — Billing and Delivered Energy The backend needs to track how much energy a charging stall delivers during a charging session so that the corresponding amount can be used for billing. The interviewer went deeply into the end-to-end communication path between the Supercharger and backend. Topics discussed included: The discussion focused on how charging and billing data should reliably reach the backend under different network conditions.
  • Request routing
  • Secure communication between the charger and backend
  • DNS and service discovery considerations
  • Local buffering when connectivity is interrupted
  • Synchronous versus asynchronous communication
• Requirement 2 — Supercharger Health and Telemetry Each charging stall also produces operational and health telemetry. The system needs to collect this information and retain it in a long-term datastore so charger health and historical behavior can be analyzed over time. This requirement was part of the original prompt, but the interview did not progress into a detailed design discussion for it.
• Requirement 3 — Nearby Available Supercharger Search The third requirement covered the customer-facing experience in the vehicle or application. A user should be able to open a map and find nearby Superchargers, including information such as: The system therefore needs to support geographic lookup of nearby charging stations together with sufficiently recent availability and pricing information. This requirement was also introduced at the beginning, but most of the interview time was spent drilling into the billing flow before reaching it in depth.
  • Location
  • Current availability
  • Charging price

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