AI & Technical question

How will you design a web service that enables other developers to create online chat applications?

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Technical product thinking for a developer-facing platform: defining core primitives, developer experience, and monetization.

Clarify the target developer: assume embeddable chat infrastructure for other apps, not a standalone consumer chat app.
Define core primitives the API must expose: message send and receive, presence and typing indicators, message history, push notification delivery.
Design the developer experience: SDKs for web, iOS, Android, clear docs, and a sandbox or free tier to drive adoption.
Address scale and reliability: delivery guarantees, latency targets, multi-region redundancy, since chat is latency-sensitive.
Define a monetization model: usage-based pricing per active user or per message, consistent with developer platforms like Stripe or Twilio.
Define success as developer activation, time to first message sent, and monthly active end-users routed through the API.

Names concrete API primitives, presence, history, push, instead of a vague chat API.
Explicitly borrows Stripe's developer-experience playbook, great docs, fast time-to-first-success, usage pricing.
Ties technical reliability requirements to the product's core promise.

Designing a consumer chat app instead of the developer platform the question asks for.
Ignoring developer experience, the real differentiator for platform products.

How would you price this to compete with existing chat APIs like Twilio or Sendbird?
What would your reliability SLA be, and how would you design around outages?