:PROPERTIES:
:ID:       e7f082e4-1b9f-4ebe-96d6-94d92e80a07e
:END:
#+title: API Intro Notes
#+filetags: :notes:api:career:technical:

**Notes from [[https://app.pluralsight.com/ilx/video-courses/apis-explained/course-overview][PluralSight]]**

* APIs Are Everywhere
- APIs power everyday digital experiences behind the scenes.
- They connect apps, data, and services seamlessly.
- Examples:
  - Checking weather
  - Banking apps
  - Booking travel
  - Sharing music
- APIs act as *connectors* between systems.

** Key Idea
APIs = invisible infrastructure enabling modern apps.

* Real-World API Examples
- Google Maps -> location, routing
- Stripe -> payments
- OpenWeather -> weather data
- Spotify -> music data & activity

** Insight
- APIs are often *products themselves*.
- They act as *building blocks* for faster development.

* What Is an API?
** Definition
API (Application Programming Interface):
- A way for systems to communicate
- Sends requests and receives responses
- Hides internal complexity

** Restaurant Analogy
- You -> Client
- Menu -> API documentation
- Waiter -> API
- Kitchen -> System/service
- Meal -> Response

** Core Components
- Request -> what is asked
- Response -> returned result
- Endpoint -> where request is sent
- Payload -> data sent with request
- Format -> structure (e.g., JSON, XML)

* Why APIs Matter
- Speed -> build faster using existing services
- Reuse -> avoid rebuilding functionality
- Focus -> teams specialize and connect via APIs

* Example: Travel App
- Flight API -> routes/prices
- Hotel API -> availability
- Weather API -> forecasts
- Payment API -> transactions

** Insight
Multiple APIs -> one seamless user experience.

* APIs in Modern Architecture
- Composability -> systems built from smaller parts
- Ecosystems -> partnerships & integrations
- AI -> APIs provide data + deliver outputs

* What APIs Are NOT
- Not just for engineers
- Not a database (they access data, don't store it)
- Not a UI (they work behind the scenes)
- Not always public (many are internal)

** Analogy
- App = stage
- API = backstage operations

* How APIs Work
** Process
1. Request sent to endpoint
2. System processes request
3. Response returned

** Data Handling
- Data is structured and standardized
- Travels in small packets
- Uses agreed formats

** Impact
- Automation of tasks
- Cross-device consistency
- Scalability

* APIs Inside a Business
- Internal APIs connect teams and systems
- Enable modular architecture

** Benefits
- Faster development
- Single source of truth
- Scalability
- Team independence

** Example
Travel app:
- Flights, Hotels, Cars, Payments -> separate services
- APIs unify them into one experience

* API as a Product
** Concept
- Companies expose APIs for external use
- Creates ecosystems and new revenue streams

** Example: Google Maps
- Released API (2005)
- Enabled:
  - Ride-sharing (Uber)
  - Travel platforms
  - Real estate apps
  - Games (Pokémon Go)

** Key Lessons
- Solve internal problem first
- Package as a product
- Enable external innovation
- Build ecosystems

** Other Examples
- Stripe -> payments
- Twilio -> communication APIs
- AWS -> cloud infrastructure
- Dropbox -> file storage APIs

* API Pitfalls
** Challenges
- Complexity increases with scale
- Dependency on external services
- Internal dependencies between teams

** Risks
- Downtime from third-party APIs
- Breaking changes
- Cost spikes (pay-as-you-go)

** Mitigation
- Rate limiting
- Bot protection
- Usage monitoring & alerts

* Why APIs Matter for the Future
** Flexibility
- Easy integration of new tools
- Easier vendor switching
- Adaptable systems

** AI Dependence
- APIs provide:
  - Input data
  - Output delivery
- Enable real-time, useful AI systems

** Strategic Importance
- APIs influence:
  - Business growth
  - Product design
  - Partnerships

* Key Takeaways
- APIs connect systems through requests and responses
- They enable speed, scalability, and innovation
- They are critical for modern software and business strategy
- Thinking in APIs -> better decisions and flexibility
