Front End Developer vs Back End Developer – Definition and Meaning In Practice

The terms "front end" and "back end" are thrown around liberally in the web development world, but what do they actually mean in practice? What differentiates a front end developer from a back end developer in terms of the work they do, the skills they need, and the technologies they use? As a full stack developer who has worked across the entire web development spectrum, I‘ll share my perspective on how these two roles differ but also work closely together.

Distinguishing The Front End from the Back End

At its core, the distinction between the front end and back end comes down to the separation of concerns between the visual, interactive parts of a website or application that users see and interact with directly (the front end), and the behind-the-scenes data access, business logic and infrastructure that powers it (the back end).

The front end encompasses everything that the end user experiences directly, including:

• The user interface (UI) and visual design
• The site layout and navigation
• Fonts, colors, buttons and other visual elements
• Interactive features and animations

All of this is accomplished with the core web technologies of HTML, CSS and JavaScript that run in the user‘s web browser.

The back end, in contrast, refers to the parts of the website or application that run on the web server and are not directly accessible to the end user. This includes:

• The web server that hosts and runs the website code
• Databases that store the application data
• APIs and services that the front end requests data from
• Core business logic and data processing

The back end is generally built using programming languages like PHP, Python, Ruby, or Java (among many others) and is responsible for processing user requests from the front end, retrieving and storing data, and sending the appropriate responses back to be displayed to the user.

Here‘s a simplified diagram of how the front end and back end typically fit together:

        Front End (Browser)              |            Back End (Server)         
                                         |                              
    [HTML/CSS/JS] <---- HTTP Requests ----> [Web Server (e.g. Apache, Nginx)]
         ^                                              |
         |                                    [Application Logic (e.g. PHP, Python, Ruby, Java)]  
         |                                              |
    [Rendered Page] <--- HTTP Responses---- [Database (e.g. MySQL, PostgreSQL, MongoDB)]

The front end sends HTTP requests to the back end, which processes them, interacts with the database and other services as needed, and sends back HTTP responses containing the data or assets (HTML, CSS, images, etc.) to render the page or update the UI in the browser.

Front End Developer Skills, Tools and Responsibilities

A front end web developer is responsible for implementing the visual and interactive elements that users engage with directly in their web browser. This includes:

• Writing semantic, accessible HTML to structure the page content
• Creating CSS styles and layouts to make the page visually appealing
• Using JavaScript and front end frameworks like React, Angular or Vue to add interactivity and animations
• Integrating with back end APIs to send and receive data
• Ensuring the site is responsive and works well on all screen sizes and devices
• Testing and debugging front end code
• Optimizing front end performance and page load speeds

According to the 2021 StackOverflow Developer Survey, the most commonly used web technologies for front end development are:

• HTML/CSS (used by 68% of professional developers)
• JavaScript (65%)
• jQuery (42%)
• React.js (40%)
• Angular (26%)
• Vue.js (19%)

Other common front end tools and technologies include:

• CSS preprocessors like Sass and Less
• Build tools and module bundlers like Webpack, Rollup and Parcel
• Testing frameworks like Jest, Mocha, Jasmine and Cypress
• Accessibility tools like WAVE and Lighthouse
• Version control systems like Git and Subversion

Front end developer salaries vary based on location, experience level and company, but according to Glassdoor, the average base pay for a Front End Developer in the United States is $86,178 per year as of May 2023.

Back End Developer Skills, Tools and Responsibilities

Back end developers are responsible for the server-side aspects of web development, including:

• Writing server-side code in languages like PHP, Python, Ruby, Java, C#, etc.
• Working with databases to store and retrieve application data
• Implementing the core business logic and data processing
• Creating and consuming APIs and web services
• Integrating with third-party services and libraries
• Managing server infrastructure and deployment processes
• Ensuring the security, scalability and performance of the back end

The back end tech stack is highly variable since there are many programming languages, frameworks, and infrastructure options available. According to the 2021 StackOverflow Developer Survey, the most popular back end frameworks are:

• Node.js (36%)
• .NET (30%)
• Django (16%)
• Spring (14%)
• Laravel (11%)
• Ruby on Rails (8%)

In terms of programming languages for back end development, the same survey lists:

• JavaScript (65%, including Node.js usage)
• Python (48%)
• Java (35%)
• PHP (22%)
• C# (27%)
• Ruby (6%)

Database technologies are another key part of the back end stack. The most commonly used databases include:

• MySQL (50%)
• PostgreSQL (40%)
• MongoDB (35%)
• SQLite (32%)
• Redis (25%)
• Oracle (10%)

Salaries for back end developers also vary, but according to Glassdoor, the average base pay for a Back End Developer in the United States is $101,619 per year as of May 2023.

How Front End and Back End Development Work Together In Practice

In practice, front end and back end developers work closely together (along with other roles like designers, dev ops engineers, QA testers, etc.) to build and maintain complete web applications. Each side has its own responsibilities but they have to integrate together to deliver a working product.

A typical workflow might look something like:

1. Designer creates wireframes and mockups of the website or application UI
2. Front end developer translates the designs into HTML, CSS and JavaScript code
3. Back end developer writes server-side code to handle data processing and storage
4. Front end and back end developers collaborate to integrate their code via APIs
5. QA team tests the complete application and reports any bugs or issues
6. Dev ops engineer handles deployment and infrastructure for the application
7. Process repeats as new features and updates are made to the application over time

Here‘s a simplified code example of how the front end and back end would integrate to display a list of blog posts:

<!-- Front End HTML -->
<div id="blog-posts">
  <!-- Blog posts will be dynamically inserted here -->
</div>

<script>
// Front End JavaScript
fetch(‘/api/posts‘)
  .then(response => response.json())
  .then(posts => {
    const postsHtml = posts.map(post => `
      <h2>${post.title}</h2>
      <p>${post.content}</p>
    `).join(‘‘);
    document.getElementById(‘blog-posts‘).innerHTML = postsHtml;
  });
</script>

// Back End PHP 
<?php
// Retrieve blog posts from the database
$posts = $db->query(‘SELECT title, content FROM posts‘);

// Return posts as JSON for the front end to consume
header(‘Content-Type: application/json‘);
echo json_encode($posts);
?>

In this example, the front end code makes an HTTP request to the /api/posts endpoint, which is handled by the back end PHP code. The PHP retrieves the blog posts from the database and returns them as a JSON response. The front end JavaScript then parses this JSON data and dynamically inserts the HTML for each blog post into the page.

This is just a simple example, but it demonstrates the basic flow of data between the front end and back end. In a real-world application, there would be many more API endpoints for creating, reading, updating and deleting data (CRUD operations), as well as much more complex UI interactions and behaviors on the front end.

The Blurring Line Between Front End and Back End

While the separation of front end and back end concerns is still a useful conceptual model, in practice the lines between the two can often blur, especially with the rise of Node.js and full stack JavaScript development.

With Node.js, it‘s possible to use JavaScript on the back end as well as the front end, which has led to the rise of "full stack" JavaScript developers who are comfortable working across the entire web stack. Frameworks like Next.js and Meteor allow you to build entire applications with JavaScript, blurring the lines between front end and back end.

Additionally, the growth of serverless architectures and cloud infrastructure has made it easier for front end developers to deploy and manage their own back ends without needing to be experts in server administration. Services like AWS Lambda, Firebase and Netlify allow developers to build and deploy full stack applications without managing servers directly.

That being said, even in these "blurred" scenarios, there is still usually some separation of concerns between the front end UI layer and the back end data and logic layer. And in many organizations, there are still specialized front end and back end developer roles, even if some individuals may work across both.

Conclusion

Front end and back end development are two essential aspects of building modern web applications. While front end developers focus on the user-facing interface and interactions, back end developers handle the server-side data processing and business logic.

The two roles require different but overlapping skill sets and technologies – HTML, CSS and JavaScript for the front end; programming languages like PHP, Python, Ruby or Java for the back end, databases like MySQL or MongoDB for data storage, etc.

In practice, front end and back end developers work closely together to integrate their code and deliver complete, functional applications to end users. The separation of concerns between the two sides is not always clear cut, especially with the rise of full stack JavaScript development, but the fundamental division of labor still exists in most cases.

Aspiring web developers should aim to learn the core technologies on both the front end and back end, and then specialize based on their interests and strengths. Strong communication and collaboration skills are also critical for working effectively across the front end/back end divide.

Whether you ultimately choose to focus on the front end, back end, or work across the full stack, understanding the role and responsibilities of both sides will make you a more well-rounded and effective developer. The modern web is built on the interplay between the front end and back end – and the developers who make it all come together behind the scenes.