Premium

News Feed / Timeline Front-End System Design

By FrontendAtlas Team · Updated Feb 1, 2026

Design a social news feed (Facebook/Instagram style) from the front-end perspective. Cover initial load, pagination/infinite scroll, virtualization, media lazy-loading, real-time updates, and smooth interactions (likes/comments) with optimistic UI. Key considerations: - Fetch strategy: initial load vs incremental pages and refresh. - Virtualized rendering to keep…

Requirements exploration
Architecture / High-level design

What you’ll build / What this tests

This premium front-end system design system design focuses on News Feed / Timeline Front-End System Design. You’ll apply infinite-scroll and virtualization thinking with intermediate level constraints. The prompt emphasizes Design a social news feed (Facebook/Instagram style) from the front-end perspective. Cover initial load, pagination/infinite scroll,….

Learning goals

Decompose News Feed / Timeline Front-End System Design into front-end components, state, and data flow.
Apply infinite-scroll, virtualization, performance constraints to a real client architecture.
Define performance budgets and UX trade-offs for the interface.
Plan instrumentation and resilience for user-facing failures.

Key decisions to discuss

Choose a data model that matches UI reads and writes.
Pick a pagination + caching strategy to keep the UI fast.
Set performance budgets (LCP/INP) and validate with telemetry.

Evaluation rubric

Architecture: clear client data flow and component boundaries.
Performance: budgets + caching/virtualization where needed.
Resilience: offline/error states and retries defined.
Observability: metrics/logs to validate UX and perf.

Constraints / Requirements

Design a social news feed (Facebook/Instagram style) from the front-end perspective. Cover initial load, pagination/infinite scroll,…
Requirements exploration
Architecture / High-level design
Data model
Interface definition (API)
Optimizations and deep dive
Assume real users and real latency; budget for perceived performance.
Define client-side caching and invalidation strategy.
Plan pagination or windowing for large UI lists.
Batch UI updates and handle reconnection/backoff.

Mini snippet (architecture sketch)

Constraints:
- P95 UI response < 200ms
- 1k+ events/sec during peak
- Focus: infinite-scroll, virtualization

Components:
- Client cache + pagination
- Realtime updates (SSE/WebSocket)
- Observability + error states

Endpoints:
- GET /feed?cursor=
- POST /events

Common pitfalls

Ignoring pagination/virtualization for long feeds.
Underestimating client performance budgets.
Overfetching data or failing to cache responses.
Skipping failure states and retry UX.