DocuSign·Software Engineer·Onsite - System Design / Architecture·Intermediate

IntermediatePrefer not to say

Jun 2026

Summary

System design round at DocuSign for a software engineer role. The problem was a multi-level parking lot which sounds straightforward but there's a lot of surface area once you start pulling on the thread of vehicles that span multiple spots.

Questions Asked (1)

Design a multi-level parking system that tracks floors, spots, and vehicle types, where some vehicles may occupy multiple adjacent spots. Define the core data models and APIs for vehicle entry and exit, spot allocation and release, and queries like available spots by type or by floor.

System DesignData ModelingAPI & Integrations

Author's notes

I started with the data model which felt right, floors containing rows of spots, each spot having a type and an availability flag.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then define core data models (Floor, Spot, Vehicle, Allocation) and APIs for entry/exit, allocation/release, and queries. Discuss allocation strategies for multi-spot vehicles, concurrency handling, and scalability considerations.

Pro tip: Emphasize idempotency and concurrency control in entry/exit APIs to prevent double-booking, and discuss how to handle partial failures in multi-spot allocation.

1. Clarify Requirements and Constraints

Ask about scale (number of floors, spots, vehicles), vehicle types and their spot requirements, and whether spots can be reserved in advance. Clarify query patterns and performance needs.

2. Define Core Data Models

Design entities: Floor (id, level), Spot (id, floorId, type, status, position), Vehicle (id, type, size), and Allocation (id, vehicleId, spotIds, entryTime, exitTime). Consider relationships and indexes for efficient queries.

3. Design APIs for Entry, Exit, Allocation, and Release

Define endpoints: POST /vehicles/entry (allocate spots), POST /vehicles/exit (release spots), GET /spots/available (filter by type/floor). Specify request/response schemas and error handling.

4. Detail Allocation and Release Logic

Explain algorithms for finding contiguous spots for multi-spot vehicles, handling fragmentation, and ensuring atomic allocation/release. Discuss concurrency control (e.g., locking, transactions) to avoid race conditions.

5. Address Queries, Scalability, and Extensions

Describe how to efficiently query available spots by type/floor (e.g., using indexes, caching). Discuss scaling (sharding by floor), monitoring, and potential extensions like reservations or dynamic pricing.

Key Points to Mention

Data model normalization and indexing for fast queries
Allocation strategy for multi-spot vehicles (e.g., first-fit, best-fit, contiguous search)
Concurrency control (optimistic vs pessimistic locking, transactions) to prevent double-booking
API design principles: RESTful endpoints, idempotency, clear error codes
Handling partial failures and rollback in multi-spot allocation
Scalability considerations: sharding, caching, and load balancing

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.