Infrastructure

DNS, TLS 1.3, load balancing, gateways, queues

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Every web request passes through multiple infrastructure layers, each adding latency but providing essential services. Understanding these components helps you optimize the critical path and make informed architectural decisions.

The key insight: connection reuse and caching are your best friends. A new HTTPS connection might take 50ms to establish (DNS + TCP + TLS), but subsequent requests on that connection take microseconds. Similarly, a cache hit is 100-1000x faster than fetching from origin.

Infrastructure Components

Typical latency ranges for each component in the request path

DNS Lookup

Cold misses dominate; prefer low TTL for agility and rely on resolvers.

10–100 ms

TLS Handshake

Amortize via connection reuse; TLS 1.3 is single RTT.

10–30 ms

Load Balancer (L7)

Keep policies simple; colocate with services.

0.5–2 ms

API Gateway

Auth and transforms live here; push slow logic to services.

5–15 ms

WAF

Inline rules; tune false positives.

1–5 ms

Message Queue

Broker hops add small latency; batch where possible.

1–10 ms

Cache Hit

Data locality is king; maximize hit rate.

0.1–1 ms

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