Systems I’ve built as a working engineer — the shipped work, the results, and the design decisions behind them.
DynamoDB — TLS Handshake Latency with AWS-LC
Swapped the cryptographic library under DynamoDB's on-host TLS termination from OpenSSL 1.0.2 to AWS-LC and deployed it to every AWS region with zero downtime: median handshake time down 12–35% by region, FIPS endpoints down as much as 80% (22 ms to 4.5 ms in us-gov-west-1). Triggered by a Graviton migration that made handshakes slower; includes the two ways the rollout bit back.
Amazon Connect — Public Phone Number APIs
Public control-plane APIs for the phone-number lifecycle in AWS's cloud contact center, built in Java: claim, import, describe, and update. Phone numbers modeled as first-class cloud resources with ARNs and tags, an asynchronous provisioning contract where FAILED is a state rather than an HTTP error, idempotency via client tokens, and a quota rule that exists because carrier inventory is physically scarce.