🧩 Big Picture

There are two types of sessions in a web app:

1. Authentication session (Cognito, tokens)
2. Application session (DynamoDB, Redis, etc.) They interact, but they serve different layers of your application.

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🔹 1️⃣ Authentication session — “Who is this user?”

• Managed by Amazon Cognito (or another identity provider).
• Exists to prove the user’s identity.
• Represented by JWT tokens (ID, access, refresh).
• Has a limited lifetime (e.g., 1 hour access token, 30-day refresh token).
• Stored on the client (browser/app), usually in cookies or local storage. 💡 Purpose: Security and authorization.

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🔹 2️⃣ Application session — “What is this user doing?”

• Managed by your application backend.
• Stored in a shared, durable store (e.g., DynamoDB or ElastiCache Redis).

Contains:

• Shopping cart contents
• Current page or step in checkout
• Temporary preferences
• In-progress transaction data

Exists while the user interacts with the site — can be tied to login, but not always. 💡 Purpose: Maintain continuity of user activity across requests.

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🔗 How they relate

• When a user authenticates (Cognito → returns JWT token), your backend validates that token.
• Once validated, your backend creates or retrieves the application session for that user (from Redis/DynamoDB).
• The application session may use the user ID from the token as a key. So, yes — the application session is often associated with the authenticated user, but it’s not dependent on the authentication system.

You could even have:

• Guest sessions (user not logged in, but cart stored via session ID).
• Authenticated sessions (user logged in, data keyed by Cognito user ID).

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⚖️ Analogy

Imagine a shopping mall:

• Cognito = Security guard at the entrance — checks who you are, gives you a pass.

• Application session = Shopping cart — holds what you’re doing inside the mall. They work together, but are two separate systems:

• Losing your cart doesn’t unauthenticate you.

• Losing your token doesn’t empty your cart (until your app decides so).

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✅ In summary

Aspect	Authentication Session	Application Session
Managed by	Cognito / Identity Provider	App backend (Redis, DynamoDB)
Purpose	Verify who the user is	Track what the user is doing
Stored where	Client (JWT tokens)	Backend store
Lifetime	Based on token expiry	Based on app logic
Relation	Often linked by user ID	Uses user ID as key (optional)

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If a question says:

“The company wants to maintain user login state” → That’s Cognito (authentication session).

If it says:

“The company wants to store session data durably or share across instances” → That’s DynamoDB or Redis (application session).