Frontend Architecture (RADIO)

Preview — 3 of 10 questions

A frontend system design interview typically follows a structured framework known by the mnemonic RADIO. What does each letter stand for, in order?

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R — Requirements exploration       (~10% of session)
A — Architecture / high-level design (~20%)
D — Data model / core entities      (~10%)
I — Interface definition (API)      (~20%)
O — Optimizations and deep dive     (~40%)

AResponsiveness, Accessibility, Data, Interactivity, Onboarding

BRendering, API, Design, Infrastructure, Observability

CRequirements, Availability, Deployment, Integration, Ops

DRequirements, Architecture, Data model, Interface, Optimizations

A candidate is asked to design a news feed application. Which of these is not one of the four typical client-side architecture layers used in the RADIO framework's Architecture step?

AView layer (components, local interaction state)

BLoad balancer layer (distributing requests across app servers)

CData access layer (fetching, caching, abstracting data origin)

DStore / model layer (cross-cutting shared state)

While designing a photo-sharing apps upload flow, a candidate lists these four pieces of data: (1) a users saved photo albums, (2) whether the upload progress modal is currently open, (3) the caption text as the user is typing it (before hitting submit), (4) the user's display name. Which pairing of type → example is correct?

AEphemeral client-only data → the user's display name

BServer-originated data → whether the upload modal is open

CEphemeral client-only data → whether the upload modal is open

DData to be persisted (client-only) → the user's saved albums

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