Backend Course Extended Index

This list covers the essential backend topics needed to build strong core fundamentals and a deeper understanding of how real systems work. In the age of AI, these fundamentals matter even more because while AI can assist in writing code, only strong engineering knowledge allows you to design scalable systems, make correct technical decisions, and build reliable production ready software.

1. High-Level Understanding

Overview of how backend systems operate.

Key ideas

Client server architecture
Request response lifecycle
Network routing
Backend infrastructure

Flow:

Client → Network → Backend Server → Application Logic → Database → Response

2. HTTP Protocol

Protocol used for communication between client and server.

Core concepts

HTTP methods
Headers
Status codes
Request and response format

Common methods

Method	Purpose
GET	fetch resource
POST	create resource
PUT	replace resource
PATCH	partial update
DELETE	remove resource

3. Routing

Routing maps incoming URLs to backend logic.

Example

GET /users → fetch users POST /users → create user

Route types

Static routes
Dynamic routes
Nested routes
Wildcard routes

4. Serialization and Deserialization

Process of converting data between program objects and transferable formats.

Process	Meaning
Serialization	Object → JSON / binary
Deserialization	JSON → Object

Formats

JSON
XML
Protocol Buffers

5. Authentication and Authorization

Concept	Meaning
Authentication	verify identity
Authorization	verify permissions

Methods

Sessions
JWT
OAuth
API keys
MFA

6. Validation and Transformation

Ensures incoming data is correct and safe.

Types

Syntactic validation
Semantic validation
Type validation

Transformations

type casting
normalization
sanitization

7. Middleware

Middleware executes during the request pipeline.

Typical order

Logging → Auth → Validation → Handler → Error handling

Common middleware

logging
authentication
rate limiting
compression

8. Request Context

Temporary request scoped data shared across layers.

Contains

request metadata
user session
request id
permissions

Used for tracing and authentication.

9. Handlers and Controllers

Controllers process requests and coordinate services.

Typical architecture

Controller → Service Layer → Data Access Layer

Responsibilities

handle HTTP request
call business logic
return response

10. CRUD Deep Dive

CRUD operations:

Operation	HTTP Method
Create	POST
Read	GET
Update	PUT / PATCH
Delete	DELETE

Includes

pagination
filtering
sorting

11. REST API Best Practices

Principles of REST API design.

Core rules

resource based URLs
stateless communication
consistent responses
HTTP semantics

Example

/users
/orders
/products

12. Databases

Systems used for persistent data storage.

Types

Type	Examples
Relational	PostgreSQL, MySQL
NoSQL	MongoDB

Important concepts

ACID
indexing
joins
transactions

13. Business Logic Layer (BLL)

Layer where application rules and domain logic exist.

Architecture layers

Presentation layer
Business logic layer
Data access layer

Responsibilities

domain rules
validation
orchestration

14. Caching

Temporary storage used to reduce database load.

Cache types

memory cache
distributed cache
browser cache

Strategies

cache aside
write through
write back

15. Transactional Emails

Emails triggered by system events.

Examples

account verification
password reset
order confirmation
notifications

Components

subject
body
CTA
dynamic parameters

16. Task Queue and Scheduling

Used for background processing.

Examples

sending emails
image processing
batch jobs

Architecture

Producer → Queue → Worker

Features

retries
prioritization
scheduling

17. Elasticsearch

Search engine optimized for full text search.

Core concepts

inverted index
shards
relevance scoring
aggregation

Use cases

search systems
log analysis
recommendation systems

18. Error Handling

Managing failures in backend systems.

Types

syntax errors
runtime errors
logical errors

Best practices

fail fast
centralized error handling
clear error messages

19. Config Management

Separating configuration from code.

Examples

database credentials
API keys
feature flags

Sources

environment variables
config files
secret managers

20. Logging, Monitoring and Observability

Three pillars of observability

Pillar	Purpose
Logs	event records
Metrics	performance numbers
Traces	request flow

Tools

Prometheus
Grafana
ELK stack

21. Graceful Shutdown

Controlled server shutdown process.

Steps
1 capture shutdown signal
2 stop new requests
3 finish active requests
4 close connections
5 terminate application

22. Security

Protecting backend systems from attacks.

Common threats

SQL injection
XSS
CSRF
broken authentication

Security principles

least privilege
defense in depth
secure defaults

23. Scaling and Performance

Improving system performance under load.

Metrics

response time
throughput
latency

Scaling types

Type	Meaning
Vertical scaling	increase machine power
Horizontal scaling	add more servers

24. Concurrency and Parallelism

Concept	Meaning
Concurrency	multiple tasks progress together
Parallelism	tasks run simultaneously

Used for improving resource utilization.

25. Object Storage and Large Files

Used to store large binary files.

Examples

AWS S3
Google Cloud Storage

Techniques

streaming
chunk upload
multipart upload

26. Real Time Backend Systems

Systems that push updates instantly.

Technologies

WebSockets
Server Sent Events
Pub/Sub systems

Examples

chat apps
live dashboards
notifications

27. Testing and Code Quality

Ensuring software correctness and maintainability.

Testing types

unit testing
integration testing
end to end testing
load testing

Code quality metrics

cyclomatic complexity
maintainability index

28. Twelve Factor App Principles

Guidelines for building scalable cloud applications.

Key ideas

configuration in environment
stateless processes
logs as event streams
disposable services

29. OpenAPI Standard

Specification for describing REST APIs.

Benefits

automatic documentation
API testing
client SDK generation

Tools

Swagger
Postman
Redoc

30. Webhooks

Server to server event based communication.

Flow

Event occurs → server sends HTTP request → receiver processes event

Examples

payment notifications
GitHub events
Slack integrations

31. DevOps for Backend Engineers

Practices for deploying and operating backend systems.

Core concepts

CI/CD pipelines
containerization
infrastructure as code

Tools

Docker
Kubernetes
GitHub Actions

Deployment strategies

rolling deployment
blue green deployment

Accessing Neural Archive...