Backend Basics

Internet Basics

  1. enter the site you want to visit
  2. computer needs to find IP address to send request to
    • query submitted to your ISP
    • within ISP, the DNS takes the domain name and turns it into an IP address
  3. going to the address
    • request sent to IP address via HTTP (hyper text transfer protocol)
    • request finds the fastest possible path to the server with the specified IP
      • this is not a direct journey --- it requires hopping from server to server until we arrive
  4. server responds
    • requested server finds out exactly what we're asking for
    • server builds the right content --- often pulling info from a database
    • server responds with any combo of HTML, CSS, and Javascript
  5. browser renders the page

Static vs Dynamic Sites


  • same HTML, CSS, and Javascript every time


  • compiled on the server side
    • server pulls everything together and constructs it before it is sent back as a response
  • can have different HTML, CSS, and/or Javascript that's being sent back every time a request is made

Stacks/Backend Technologies

  • a generic stack:
    Backend language/app server database
    ---------------------- -------- ----------
    HTML/JS/CSS ➡︎ website
    Note:dashed row separates backend from frontend
    • HTML, CSS, and Javascript are almost always part of a stack
    • much more variance in the backend
      • languages: ruby, python, scala, java, php, javascript, etc.
      • databases: mongo, postgres, mysql, etc.
  • example of Reddit's stack:
    Python/Flask nginx postgresql
    ---------------------- -------- ------------
    HTML/JS/CSS (Backbone) ➡︎ Reddit site
  • backend is where the dynamic part of the site comes in
    • examples of possible backend features:
    check if the user is logged in sign up user remove post from DB
    figure out what js/html/css to send the user add new post to DB sort/rank posts
    create new comment create subreddit
    add to newsletter
    -------------------------------- -------------------- ---------------------
    HTML/JS/CSS ➡︎ website
  • stack for Web Developer Bootcamp (Udemy class):
    Node JS Express MongoDB
    ------------- -------- --------------
    HTML/JS/CSS ➡︎ project site
  • example of going to a website and then searching for 'dogs':
    Frontend Backend
    1. ask for homepage
    2. send back home page content
    3. browser renders home page
    4. user enters 'dogs' in the search and submits form
    5. finds all posts in DB about 'dogs'
    6. sends back HTML for the search results page
    7. browser renders search page

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