Step 5: Understand the Architecture - Simply Readable Walkthrough

Learn how 12 AWS services orchestrate document translation and Easy Read

Step 5 of 5 • 7 minutes

Step 5 7 minutes

Understand the Architecture

Look under the bonnet to see how 12 AWS services work together in an event-driven architecture to power document translation and Easy Read.

Step Functions console showing the 15 state machines that orchestrate the translation and Easy Read workflows

Expected outcome

• ✓ You understand the high-level architecture
• ✓ You can identify the key AWS services and their roles
• ✓ You understand the event-driven data flow
• ✓ You can explain the architecture to a colleague

Architecture overview

Simply Readable is a fully serverless application. There are no servers to manage, no databases to maintain, and no infrastructure to patch. Everything runs on managed AWS services that scale automatically and charge only for what you use.

High-level architecture: Users interact with a React frontend on CloudFront. Cognito handles authentication. AppSync provides real-time GraphQL. DynamoDB stores job state, and EventBridge Pipes trigger Step Functions workflows that orchestrate Lambda, Amazon Translate, and Amazon Bedrock.

View architecture as text

AWS Services Used

Layer	Service	Purpose
Frontend	Amazon CloudFront + S3	Hosts the React web application globally
Auth	Amazon Cognito	User authentication and identity-scoped access
API	AWS AppSync	Real-time GraphQL API with subscriptions
Security	AWS WAF	Web application firewall protecting the API
Storage	Amazon S3	Document storage with identity-scoped prefixes
Data	Amazon DynamoDB	Job tracking and status management
Events	Amazon EventBridge Pipes	Connects DynamoDB Streams to Step Functions
Orchestration	AWS Step Functions	Orchestrates multi-step translation and Easy Read workflows
Compute	AWS Lambda	12+ functions for document processing, admin setup, and more
AI	Amazon Translate	Document translation into 75 languages
AI	Amazon Bedrock (Claude 3 Haiku)	Text simplification for Easy Read
AI	Amazon Comprehend	Language detection for uploaded documents

Event-driven architecture

Simply Readable uses an event-driven pattern. Rather than a traditional request-response model, the system reacts to events:

1. User uploads a document -- the React app uploads directly to S3 using Cognito-authenticated credentials, then writes a job record to DynamoDB via AppSync.
2. DynamoDB Stream fires -- the new job record triggers a DynamoDB Stream event.
3. EventBridge Pipes routes the event -- the stream event is filtered and transformed by EventBridge Pipes, which starts a Step Functions execution.
4. Step Functions orchestrates the workflow -- the state machine calls Lambda functions that interact with Translate, Bedrock, and S3.
5. Status updates flow back -- Lambda functions update the DynamoDB job record, which AppSync picks up via subscriptions and pushes to the browser in real-time.

Why event-driven? This pattern means there are no always-on servers. Each component only runs when needed, keeping costs near zero when the system is idle. It also scales naturally -- if 100 documents are uploaded simultaneously, Step Functions runs 100 parallel workflows.

Explore in the AWS Console

To see the architecture in action, explore these AWS Console pages while a job is running:

Step Functions

View state machines -- see the visual workflow and execution history

DynamoDB

View tables -- see job records and their status changes

S3

View buckets -- see uploaded and translated documents in identity-scoped folders

CloudWatch Logs

View log groups -- see Lambda function logs for debugging

For a deeper dive into the architecture, visit the How It Works page after completing the walkthrough.

Need help?

If you're stuck, check the troubleshooting section or contact us.

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