Duolingo English Test leverages AWS to deliver a secure, AI-powered language assessment platform with isolated infrastructure and real-time scoring. Test takers connect through AWS WAF and CloudFront for DDoS protection and global content delivery, routing to an ECS/EKS test delivery engine that orchestrates session state in DynamoDB and secure recording storage in S3. Amazon SageMaker performs real-time scoring and anomaly detection, while Amazon Polly generates neural audio stimuli for listening comprehension sections. AWS Organizations and IAM enforce compliance boundaries and least-privilege access across the isolated DET account, ensuring test integrity and regulatory adherence. Fork this diagram to customize security policies, scaling parameters, or ML model configurations for your own high-stakes assessment workload. This architecture demonstrates how to combine containerized delivery, managed ML services, and strict isolation controls for mission-critical testing platforms.