Work — Han Cao

Amazon Web Services

Amazon Lex

Jun 2024
Present

Public AWS Feature

Bot Analyzer

LLM-driven configuration analysis for Amazon Lex chatbots, surfacing alignment with AWS best practices through public API and the Lex console. Designed and shipped across 11 AWS regions — end to end.

Benchmarked 12 LLMs on accuracy, latency, and cost. Built async pipeline with Step Functions, Bedrock, and DynamoDB. MapReduce architecture for parallel intent processing.

1,000₊

Analyses in 4 days

AWS Regions

<60_s

For 1,000+ intent bots

LLMs benchmarked

Cross-Service Feature

Multimodal Dialogue

SMS input capture during live voice (IVR) calls without interrupting the session. Extended bot channel APIs to integrate AWS End User Messaging with Amazon Connect.

Evaluated native channel vs. Lambda-based extensibility. Chose control-plane-driven design for backward-compatible multi-channel growth. Delivered Private Beta across 4 teams.

Teams coordinated

Call interruptions

Private
Beta

Enterprise shipped

Amazon Web Services

AWS Lambda

Aug 2022
Jun 2024

Infrastructure

Region Build Automation

Led automation of Lambda EventBridge control plane region builds — on the critical path for every new Lambda region launch. Replaced a fully manual expansion process, eliminating human error from the build sequence entirely.

Redesigned orchestration model and CI/CD pipeline. Parallelized serial IA-gating tasks. Onboarded to automated region config and resource provisioning systems.

2.8_×

Build speed improvement

14→5

Days per build

Errors & manual steps

Reliability

Control Plane Throttling

Co-designed a multi-dimensional token bucket throttling system extending from account-level to Org ID and caller principal. Prevents cross-tenant traffic spikes from triggering availability incidents across the Lambda fleet.

Per-host local token cache with async background sync to central data plane. Throttle decisions removed from the request hot path. Load tested at ~7× normal traffic.

<25_ms

p99 latency overhead

7_×

Traffic load tested

50K₊

Throttle cache keys