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EasyFoundationsStorage And Delivery

Design URL Shortener

Build a scalable URL shortening service that supports creation, redirection, caching, and analytics ingestion for a fast user experience.

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What to build

  • Create a short URL for a valid long URL with optional custom alias, expiration time, and owner metadata.
  • Redirect a short URL to the original destination while handling missing, disabled, or expired links.
  • Record click events with timestamp, referrer, coarse geography, device type, and short code.
  • Expose basic link management for authenticated owners, including list, disable, and update expiration.

Constraints

  • Support high read throughput for redirects.
  • Keep short URLs available with low latency and cache hit rates.
  • Ingest click analytics asynchronously.

Core flows

  • Create short URL: Create mapping and optionally cache.
  • Redirect short URL: Serve redirect from cache if available.

Quality targets

  • Performance: Serve cached redirects with very low latency and keep the redirect path minimal.
  • Scalability: Optimize for read-heavy traffic with horizontal stateless services, cache replication, and partitioned storage.
  • Availability: Keep redirects available during partial database or analytics pipeline outages.

Operating envelope

Scale targets

Redirects/secThroughput
20,000
Creates/secThroughput
200
Redirect p95Latency
< 75ms
Short linksScale
100M
Analytics lagFreshness
< 10min

Nudges, not spoilers

Starter hints

Keep redirects thin

Pitfall

The redirect path should avoid synchronous analytics writes; resolve, validate, redirect, then emit click events asynchronously.

Short code generation

Starter

Use a collision-safe strategy such as random codes with retries or generated IDs encoded into a compact alphabet.

Architecture concepts

Start with these concepts, then connect the request path in the workspace.

ClientAPI GatewayURL ServiceNoSQL DatabaseRedis CacheRate Limiter

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