Code is constantly evolving. New features get added, the user base grows, or tools and resources get deprecated or go offline. There are constant reasons why a codebase is constantly changing. This complexity can make working with code dreadfully inefficient. It can also make tools underperform due to inefficient code. If you hope for your apps, software, and APIs to be their best, it’s important to overhaul your codebase from time to time.

This is known as code refactoring. While code refactoring is always an important part of keeping code running its best, it’s especially important for APIs, microservices, and AI systems, where performance is so important and uptime is so key. With that in mind, we’ve put together a thorough guide to code refactoring with everything you need to know to keep your codebase running at its absolute best.

What Is Code Refactoring?

Code refactoring is the technical term for changing code without affecting its functional output. It often involves reorganizing existing code, either due to simplifying functions, improving naming conventions, removing duplicate code, or organizing files. Code refactoring’s primary goal is to make code more readable, easier to maintain, and scalable.

Unlike adding new functionality, code refactoring doesn’t create any new features or add any bells and whistles. It just ensures your existing code performs its best. This means it sometimes gets overlooked, as maintenance and upkeep tend not to be as exciting as growth and expansion. It’s possibly even more important for a product’s longevity and success, however.

Why Code Refactoring Matters

Think of the saying “an ounce of prevention is worth a pound of the cure.” That’s to say it’s better to prevent issues before they happen than to try and fix them once they’ve happened. Preventing problems is just one reason why code refactoring matters, though. It also helps to make code more readable, which improves onboarding as well as making the code easier to maintain.

Code refactoring tends to make testing and debugging easier. Refactoring your code often results in simplified functions, which are much faster and easier to test. Code refactoring can result in a 15% reduction in execution time as well as a 30% reduction in cyclomatic complexity, which is a metric for measuring the complexity of a function.

Efficient, well-documented code is also good for AI and intelligent development environments to work with and understand. Complex code can take up to 124% longer to debug than its more efficient counterpart. Efficient code is also far easier to use. Code refactoring can result in 62% faster onboarding times for new developers. It also helps guarantee that API documentation remains up-to-date, further improving the onboarding process. Refactored code is also 27% easier to maintain.

Code Refactoring For API Design

Code refactoring is especially important for API developers, especially if they’re developing backend services that support frontend applications, mobile apps, or third-party integrations. Fast, efficient APIs are key for competitive, reliable tools and software.

Refactored APIs tend to have much less latency, for one thing. Messy backend code can result in duplicate calls, redundant database queries, or unnecessary authorization. Code refactoring can streamline request handling, reduce processing time, and improve user experience. It can also make your API more stable, as it makes clearer boundaries between backend functions. This also helps APIs to perform more consistently.

For example, consider this API for updating a blog:

from flask import Flask, request, jsonify

app = Flask(__name__)

# Global data store (bad practice)
all_blogs = []

@app.route('/make-blog', methods=['POST'])
def make_blog():
    d = request.get_json()
    all_blogs.append(d)
    return jsonify({'status': 'ok', 'data': d})

@app.route('/get_blog', methods=['GET'])
def get_blog():
    t = request.args.get('title')
    for blog in all_blogs:
        if blog.get('title') == t:
            return jsonify({'0': {
                'a': blog.get('title'),
                'b': blog.get('text'),
                'c': blog.get('authorName'),
                'd': 'yesterday'
            }})
    return jsonify({'error': 'no such blog'})

@app.route('/update_blog_post/<id>', methods=['POST'])
def update_blog_post(id):
    body = request.get_json()
    try:
        i = int(id)
        all_blogs[i]['title'] = body.get('newTitle', all_blogs[i]['title'])
        all_blogs[i]['text'] = body.get('updated_body', all_blogs[i]['text'])
        return jsonify({'msg': 'done'})
    except:
        return jsonify({'msg': 'fail'})

@app.route('/remove-post/<num>', methods=['GET'])
def remove(num):
    try:
        del all_blogs[int(num)]
        return jsonify({'deleted': True})
    except:
        return jsonify({'deleted': False})

if __name__ == '__main__':
    app.run(debug=True)

This API is full of inefficient code. It disregards common naming conventions, using naming endpoints make-blog or get_blog instead of using a simple \blog endpoint. It also uses the wrong HTTP methods, like using GET to delete a post.

Here’s an example of what the refactored code looks like:

from flask import Flask, request, jsonify, abort

app = Flask(__name__)

# Simulated in-memory database
blog_posts = []
post_counter = 1

# Helper function to find post by ID
def find_post(post_id):
    return next((post for post in blog_posts if post['id'] == post_id), None)

@app.route('/posts', methods=['POST'])
def create_post():
    global post_counter
    data = request.get_json()

    if not data or 'title' not in data or 'content' not in data or 'author' not in data:
        abort(400, description="Missing required fields: title, content, author")

    post = {
        'id': post_counter,
        'title': data['title'],
        'content': data['content'],
        'author': data['author']
    }
    blog_posts.append(post)
    post_counter += 1
    return jsonify(post), 201

@app.route('/posts/<int:post_id>', methods=['GET'])
def get_post(post_id):
    post = find_post(post_id)
    if not post:
        abort(404, description="Post not found")
    return jsonify(post)

@app.route('/posts/<int:post_id>', methods=['PUT'])
def update_post(post_id):
    post = find_post(post_id)
    if not post:
        abort(404, description="Post not found")

    data = request.get_json()
    post['title'] = data.get('title', post['title'])
    post['content'] = data.get('content', post['content'])
    post['author'] = data.get('author', post['author'])

    return jsonify(post)

@app.route('/posts/<int:post_id>', methods=['DELETE'])
def delete_post(post_id):
    post = find_post(post_id)
    if not post:
        abort(404, description="Post not found")

    blog_posts.remove(post)
    return jsonify({'message': 'Post deleted successfully'})

if __name__ == '__main__':
    app.run(debug=True)

This code creates a single endpoint that can be interacted with in numerous ways. It also creates a unique ID for each blog post, which can be accessed via the /posts endpoint.

Finally, code refactoring makes for more precise, more understandable monitoring. With smaller, more well-defined functions, it’s easier to track the flow of requests, record metrics, and debug issues.

Best Practices For Code Refactoring In API Design

Code refactoring requires a thoughtful, strategic, and systematic approach. The first best practice for code refactoring is to follow the don’t repeat yourself (DRY) approach. API backends can sometimes have repeat logic for tasks like data validation, error handling, or authorization. The simple task of transforming code into reusable functions can make an API quite a bit more efficient.

When you’re refactoring your API code, it’s important to put API testing in place before you begin. API testing lets you verify that your API is performing as it should, to verify that code refactoring doesn’t change the output. For API systems using object-oriented frameworks, API developers should focus on composition over inheritance. Inheritance can provide shared behavior, but it often results in tangled and rigid class hierarchies. Composition allows developers to create small, reusable functions that can be wired together into efficient tools.

Last but not least, it’s essential to regularly refactor your code. Focusing on efficiency too much can result in inefficiency, ironically enough. It’s better to just regularly perform code refactoring as part of your API lifecycle management routine. A report from GitHub finds that code left to its own devices, with no upkeep or maintenance, can slow down development speed up to 40% over time. Making incremental changes, rather than major overhauls, can help surface performance issues and bottlenecks that might cause service outages.

Consider the case of ShopBack, a monolithic eCommerce solution with over 6,000 lines of code. Overhauling a codebase of that size would be prohibitively expensive and time-consuming. Instead of doing a major overhaul, one of the software engineers refactored the code over time, adding an abstraction layer, an API contact list, and business logic over a span of time. Not only did this improve user experience, but it also allowed ShopBack to grow its team, as it allowed less experienced developers to become more comfortable and gain more experience in the system.

Final Thoughts On Code Refactoring

Code refactoring is one of the most powerful tools in a developer’s toolkit.
It transforms tangled, messy code into a clean, well-organized system, making the code more efficient and easier to maintain. It’s arguably more important for API developers, as it’s imperative for APIs to remain highly performant. Good API design delivers faster, more reliable responses, prevents redundancy, and improves collaboration between teams.

Code refactoring is only going to become more important as AI becomes an API consumer. Clean, well-documented modular code is far easier for AI to work with and understand. Following the DRY principle, implementing and optimizing abstraction layers, and making small, incremental changes all require regular, ongoing effort.

Code refactoring may not be as flashy or as exciting as other aspects of software development, but it’s one of the most important aspects of a successful product. It helps guarantee that your API will be ready for anything for as long as it remains on the market.