How do I approach System Design interview questions?

System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

What difficulty level is this interview question?

This is a medium difficulty System Design question, commonly asked during Take-home Project rounds at Akuna Capital.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Akuna Capital during technical interviews.

Design user communication manager APIs | Akuna Capital Interview Question

Quick Overview

Design user communication manager APIs evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

Design user communication manager APIs

In-Memory Communication Manager (Bidirectional Sessions)

Goal

Design a lightweight, in-memory manager that tracks bidirectional user-to-user sessions (think direct-message sessions). Provide 2–3 API functions:

connect(userA, userB): establish a bidirectional session.
disconnect(userA, userB): terminate the session.
clear(userA, userB): remove session state/history while keeping users connected.

Requirements

Specify method signatures (language of your choice), key data structures (e.g., hash maps, adjacency sets), and expected time/space complexities.
Discuss edge cases (duplicate connects, self-connects, missing sessions) and how to handle invalid inputs.
Describe concurrency handling and guarantees.
Include a brief testing plan.

Assume user IDs are strings (or integers) and all data lives in a single process. No persistence is required.

Constraints & Assumptions

Preserve the scope, facts, inputs, and requested outputs from the prompt above.
If the prompt leaves a detail unspecified, state a reasonable assumption before relying on it.
Keep the answer interview-ready: concise enough to present, but concrete enough to implement or evaluate.

Clarifying Questions to Ask

Clarify users, core use cases, read/write patterns, scale, latency, availability, and data retention.
State explicit assumptions before making sizing or architecture decisions.
Prioritize the functional path first, then address reliability, security, observability, and rollout.

What a Strong Answer Covers

A scoped requirements summary with concrete non-goals and success metrics.
API, data model, architecture, consistency, capacity, and operations.
Reasoned trade-offs among simple and scalable designs, including bottlenecks and failure modes.
A validation, monitoring, migration, and launch plan appropriate for the risk level.

Follow-up Questions

What breaks first at 10x traffic or data volume?
How would you degrade gracefully during dependency failures?
What metrics and alerts would prove the design is healthy after launch?

Quick Overview

Goal

Design a lightweight, in-memory manager that tracks bidirectional user-to-user sessions (think direct-message sessions). Provide 2–3 API functions:

connect(userA, userB): establish a bidirectional session.

disconnect(userA, userB): terminate the session.

clear(userA, userB): remove session state/history while keeping users connected.

Requirements

Specify method signatures (language of your choice), key data structures (e.g., hash maps, adjacency sets), and expected time/space complexities.

Discuss edge cases (duplicate connects, self-connects, missing sessions) and how to handle invalid inputs.

Describe concurrency handling and guarantees.

Include a brief testing plan.

Assume user IDs are strings (or integers) and all data lives in a single process. No persistence is required.

Constraints & Assumptions

Preserve the scope, facts, inputs, and requested outputs from the prompt above.

If the prompt leaves a detail unspecified, state a reasonable assumption before relying on it.

Keep the answer interview-ready: concise enough to present, but concrete enough to implement or evaluate.

Clarifying Questions to Ask

Clarify users, core use cases, read/write patterns, scale, latency, availability, and data retention.

State explicit assumptions before making sizing or architecture decisions.

Prioritize the functional path first, then address reliability, security, observability, and rollout.

What a Strong Answer Covers

A scoped requirements summary with concrete non-goals and success metrics.

API, data model, architecture, consistency, capacity, and operations.

Reasoned trade-offs among simple and scalable designs, including bottlenecks and failure modes.

A validation, monitoring, migration, and launch plan appropriate for the risk level.

Follow-up Questions

What breaks first at 10x traffic or data volume?

How would you degrade gracefully during dependency failures?

What metrics and alerts would prove the design is healthy after launch?

Design user communication manager APIs

Quick Overview

Design user communication manager APIs

Design user communication manager APIs

In-Memory Communication Manager (Bidirectional Sessions)

Goal

Requirements

Constraints & Assumptions

Clarifying Questions to Ask

What a Strong Answer Covers

Follow-up Questions

Submit Your Answer to Earn 20XP

Design user communication manager APIs

Quick Overview

Design user communication manager APIs

Design user communication manager APIs

In-Memory Communication Manager (Bidirectional Sessions)

Goal

Requirements

Constraints & Assumptions

Clarifying Questions to Ask

What a Strong Answer Covers

Follow-up Questions

Submit Your Answer to Earn 20XP