Best practices for AWS network latency optimisation: Get users faster data

Network latency is the speed of light problem plus routing inefficiency. Data is slow across distance. Routing adds more distance.

Geography is the foundation

Put your application near your users. London users on London servers. Frankfurt users on Frankfurt servers. Not negotiable.

But multi-region is expensive. Most applications serve global users from 1-2 regions plus edge caching.

AWS Local Zones bring services to major cities. London, Dublin, Paris. Lower latency, higher cost. Use for latency-critical applications.

Use CloudFront for content

CloudFront caches static and dynamic content at 400+ edge locations. User in Tokyo requests image. CloudFront fetches from origin (London) once. Serves 1000 times from Tokyo edge.

Reduces origin latency by 50-90%. Free tier: 1TB/month.

Cache static aggressively. Cache dynamic content carefully (staleness risk).

Use Global Accelerator for routing

Global Accelerator optimizes traffic through AWS backbone. Users hit nearest edge, traffic goes through AWS network (fast), exits near application.

Reduces latency 20-60% vs internet routing. Fixed hourly cost £0.025/hour.

Use for non-HTTP traffic, static IPs, lowest latency requirements.

Optimize at application level

Reduce payload size. Compress responses. Use gzip. Remove bloat.

Reduce round trips. Batch requests. Use HTTP/2 (single connection, multiple requests).

Reduce computation time. Cache database results. Use ElastiCache for hot data.

Profile and measure. Use CloudWatch. Monitor P50, P99 latency. Don't optimize P50 at the expense of P99.

Use Private connectivity

Direct Connect removes internet variability. Dedicated connection from your datacenter to AWS. Consistent, fast.

Expensive. £1,000-10,000/month per connection.

VPC endpoints for S3, DynamoDB. Free. Removes cross-region hops for common services.

Monitor and iterate

CloudWatch metrics: latency, throughput, packet loss.

Real User Measurement (RUM) shows actual user experience. Synthetic tests show controlled experience. Both needed.

Set baselines. Measure improvements. Don't optimize endlessly.

Where Critical Cloud comes in

Latency problems are usually multi-layered. Geography + routing + caching + application code. Pinpointing the bottleneck requires deep visibility.

We're Powered by Datadog accredited. We instrument latency from user to application. You see where time is spent.

If application latency is hard to diagnose, see how Critical Support works.