APIs

Interacting with 3rd party services to build custom applications! 

What are they?

What are they?

  • Essentially a standard way to interact with a system
  • Usually via libraries / SDKs

System A

System B

System C

Read data from

System C via

System C's API

Send data to

System B via

System B's API

What are they?

  • Maybe you have a calendar app that lists all events on a calendar
    • Read data from Google Calendar
  • And allow people to sign up to receive emails about the event
    • Sign them up to receive email updates

Your App

Mail Chimp

Google Calendar

Read events in Google Calendar and display them in your app

Send register user details to Mailchimp to receive

mail outs

Why use them?

  • Similar to webhooks
    • Allow you to use existing (and hopefully powerful) systems without having to build your own
  • Building customized functionality
    • Especially that fits into particular workflows to easy adoption

What do they look like?

$ curl https://api.intercom.io/users \
-X POST \
-H 'Authorization:Bearer <Your access token>' \
-H 'Accept: application/json' \
-H 'Content-Type: application/json' -d '
{
  "user_id": "25",
  "email": "wash@serenity.io",
  "name": "Hoban Washburne"
}'
import io.intercom.api.User;
import io.intercom.api.Intercom;

Intercom.setToken(MY_TOKEN);
User user = new User()
    .setEmail("wash@serenity.io")
    .setUserId("25")
    .setName("Hoban Washburne");
User created = User.create(user);

require 'intercom'
intercom = Intercom::Client.new(token: MY_TOKEN)
user = intercom.users.create(email: "wash@serenity.io", 
  name: "Hoban Washburne", user_id: "25")

Your App

System B

Send data

Receive response

$ curl https://api.intercom.io/users \
-X POST \
-H 'Authorization:Bearer <Your access token>' \
-H 'Accept: application/json' \
-H 'Content-Type: application/json' -d '
{
  "user_id": "25",
  "email": "wash@serenity.io",
  "name": "Hoban Washburne"
}'

The breakdown of a request

  • Authorization / Authentication
  • Format the client Accepts
  • Format the client is sending
  • Data

Things can be optional!

Authorization / Authentication

$ curl https://api.intercom.io/users \
-X POST \
-H 'Authorization:Bearer <Your access token>' \
-H 'Accept: application/json' \
-H 'Content-Type: application/json' -d '
{
  "user_id": "25",
  "email": "wash@serenity.io",
  "name": "Hoban Washburne"
}'

API Key / Access Token

  • Simple
  • Usually for accessing your own data
    (best used for internal tools)
  • Has a single kind of permission level

Authorization / Authentication

OAuth

  • Best for reading user data e.g. your app provides a service to people and allows them to give your app access to their resources. E.g. social media tool
  • Individual tokens for each person

Authorization / Authentication

OAuth

  • More varied permissions
  • Ability to allow / deny specific permissions
  • More complicated

Authorization / Authentication

Authorization / Authentication

On to the code!

  • I'm on the different version and I don't want to break existing projects
  • Versions managers to the rescue!
  • Use different versions without messing up your existing installations
  • IDEs

Playing by their rules

Playing by their rules

Playing by their rules

Playing by their rules

Exploring APIs

Exploring APIs

REST Clients: Make direct API requests:​​​ Postman / Insomnia

Exploring APIs

Request Collections

Exploring APIs

What if they don't have an API?

  • Build your own!
  • Scrape the site (be aware of any usage policy / don't be an idiot)

What if they don't have an API?

Webhooks + APIs

Q & A

APIs

By Timothy Lim

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