f:"$Sreact.suspense" 10:I[44259,["2615","static/chunks/2615-12c55f784717d5ce.js","1949","static/chunks/1949-17f98f7587a4f02c.js","7081","static/chunks/7081-ac9bd11548798879.js","348","static/chunks/348-27201387c4847ec7.js","4186","static/chunks/app/ai-interview-prep-system-design-hld/mock/%5Bslug%5D/page-2fc1fa2fef164481.js"],"HldMockShell"] 11:T6b5,%% URL Shortener — Production HLD %% FR1 POST /shorten — write path %% FR2 GET /{shortId} — hot read, p95 < 50 ms %% FR3 Custom alias — uniqueness check on write %% FR4 Click analytics — out-of-band of redirect flowchart LR Client([Browser / Client]) subgraph Edge["Edge (multi-region, 200+ POPs)"] CDN[["CDN edge cache
301 cached, single-flight"]] end GW{{"API Gateway
TLS · auth · token-bucket rate-limit"}} subgraph WriteTier["Write tier (stateless)"] Write["Write Service
POST /shorten"] IDGen[("Snowflake ID Gen
partitioned counter, base62")] Alias["Alias Validator
uniqueness check + reservation"] end subgraph ReadTier["Read tier (stateless, autoscaled per region)"] Read["Read Service
GET /{id}"] end Redis[("Redis cluster
TTL 1d + jittered
p99 < 1 ms")] KV[("Wide-column KV
DynamoDB / Cassandra
multi-region active-active reads
11 9s durability · ~3 TB")] Acct[("Postgres
users, plans, quotas")] Safe["Safe-Browsing Check"] Kafka[["Kafka click_events
async, never blocks redirect"]] WH[("Warehouse
BigQuery / Snowflake
partitioned by short_id")] Stats["Stats Service
GET /links/{id}/stats"] Client -- "POST /shorten" --> GW Client -- "GET /{id}" --> CDN CDN -- "miss (5% of hot)" --> GW GW --> Write Write --> Alias Alias -- "reserve" --> KV Write --> IDGen Write -- "PUT mapping" --> KV Write -- "warm + jittered TTL" --> Redis Write -. "async scan" .-> Safe GW --> Read Read -- "GET" --> Redis Redis -- "miss → single-flight" --> KV Read -. "async event" .-> Kafka Kafka --> WH WH --> Stats Stats --> GW Write -->