Backend Systems

Outcomes

• Trace a backend request through validation, domain work, persistence, asynchronous side effects, and failure handling.
• Reason about database and concurrency choices using correctness and operability constraints.
• Design retryable and asynchronous workflows with explicit idempotency and delivery semantics.

Path

1. Backend Request Lifecycle

   Target depth: operate

   Available Atlas content

   • Backend Request Lifecycle

2. API Design

   Target depth: operate

   Available Atlas content

   • API Design
   • Reliable Checkout Walkthrough

3. Authentication and Authorization

   Target depth: operate

   Available Atlas content

   • Auth Debugging Field Guide: 401, 403, CORS, Redirects, Issuer, Audience & Claims
   • Authentication & Authorization
   • Frontend Authentication Architecture: SPA vs BFF with OIDC & Keycloak

4. OAuth and OIDC

   Target depth: reason

   Available Atlas content

   • Auth Debugging Field Guide: 401, 403, CORS, Redirects, Issuer, Audience & Claims
   • OAuth 2.0 & OpenID Connect: Trace the Browser Login Flow
   • Frontend Authentication Architecture: SPA vs BFF with OIDC & Keycloak

5. Single Sign-On and Identity Federation

   Target depth: reason

   Available Atlas content

   • Single Sign-On & Identity Federation: Sessions, Trust, OIDC, SAML, and CAS

6. Backend Concurrency

   Target depth: reason

   Available Atlas content

   • Backend Concurrency: Preserve Invariants When Requests Overlap

7. Background Jobs

   Target depth: reason

   Available Atlas content

   • Background Jobs: Make Work Durable Beyond the Request
   • Reliable Checkout Walkthrough
   • Reliable File Processing Pipeline Walkthrough

8. Application Caching

   Target depth: reason

   Available Atlas content

   • Application Caching: Trade Freshness for Less Work Deliberately

9. Message Queues

   Target depth: reason

   Available Atlas content

   • Message Queues: Make Delivery and Completion Explicit
   • Reliable Checkout Walkthrough
   • Reliable File Processing Pipeline Walkthrough
   • Queue vs Event Stream

10. Rate Limiting

    Target depth: reason

    Available Atlas content

    • Rate Limiting: Control Admission, Bursts, and Fairness

11. Idempotency

    Target depth: operate

    Available Atlas content

    • Idempotency: Make Retries Safe Across Ambiguous Outcomes
    • Reliable Checkout Walkthrough

12. Service Resilience

    Target depth: operate

    Available Atlas content

    • Service Resilience: Contain Failure Before It Cascades

13. Relational Data Model

    Target depth: reason

    Available Atlas content

    • Relational Data Model: Put Business Facts Under Constraints

14. Database Indexes

    Target depth: operate

    Available Atlas content

    • Database Indexes & Query Plans: Choose Access Paths with Evidence

15. Query Plans

    Target depth: operate

    Available Atlas content

    • Database Indexes & Query Plans: Choose Access Paths with Evidence

16. Database Transactions

    Target depth: operate

    Available Atlas content

    • Database Transactions & Isolation: Preserve Invariants Under Concurrency
    • Reliable Checkout Walkthrough

17. Transaction Isolation

    Target depth: reason

    Available Atlas content

    • Database Transactions & Isolation: Preserve Invariants Under Concurrency

18. Partial Failure

    Target depth: reason

    Available Atlas content

    • Partial Failure: Reason About Unknown Outcomes
    • Timeouts, Retries & Backoff: Bound Failure Without Amplifying It
    • Reliable Checkout Walkthrough
    • Reliable File Processing Pipeline Walkthrough
    • Monolith vs Modular Monolith vs Microservices

19. Timeouts

    Target depth: operate

    Available Atlas content

    • Timeouts, Retries & Backoff: Bound Failure Without Amplifying It
    • Timeouts: Operate With Explicit Time Budgets

20. Retries and Backoff

    Target depth: operate

    Available Atlas content

    • Retries and Backoff: Recover Without Amplifying Failure
    • Timeouts, Retries & Backoff: Bound Failure Without Amplifying It
    • Reliable Checkout Walkthrough
    • Reliable File Processing Pipeline Walkthrough

21. Delivery Semantics

    Target depth: reason

    Available Atlas content

    • Delivery Semantics: Reason About Loss, Duplicates, and Effects
    • Reliable Checkout Walkthrough
    • Reliable File Processing Pipeline Walkthrough
    • Queue vs Event Stream

22. Transactional Outbox

    Target depth: operate

    Available Atlas content

    • Transactional Outbox: Publish Events Without a Dual-Write Gap
    • Reliable Checkout Walkthrough