5 Common Mistakes Developers Make When Deploying Web Apps — And How to Fix Them

Web app development is quite common nowadays. This is due to the proliferation of the internet and society’s increased dependency on it. One of the best ways to interact with the internet and use it as a resource is to use web apps.

Web applications are online software that run on powerful servers instead of a client’s device. As a result, they can leverage far more resources than those available in a personal computer or smartphone. That’s why they are extremely powerful.

They are also easy to use because you don’t need to install them on your devices locally. That’s why every kind of software company has switched to creating web apps and SaaS services to cash in on the internet’s chokehold on the IT sector.

However, many developers make mistakes due to inexperience or tight development cycles. Let’s examine some common mistakes developers make when deploying web apps and how to address them.

1. Inadequate Input Sanitization

Input sanitization refers to making sure that any user input cannot interact with the rest of your web app code outside of its intended use. This is called input sanitization.

Bad input sanitization can result in big problems. Some of the common things a bad actor can do in a system without input sanitization are:

  • SQL Injection:
    Attackers can inject malicious SQL code into input fields (like login forms) and gain unauthorized access to your database.
  • Cross-Site Scripting (XSS):
    Unsanitized input can allow users to inject harmful scripts into web pages, which can steal cookies, session tokens, or other sensitive data from other users.
  • Command Injection:
    If user input gets passed into system commands without sanitization, attackers can execute arbitrary commands on your server.

These are powerful attacks that can result in data leaks, which can further result in financial loss or identity theft and other terrible outcomes.

How to Fix it?

To fix input sanitization, developers need to employ best practices such as:

  • Use HTTP encoding to disable input from interacting with the website code.
  • When displaying user-generated content, always escape it to prevent scripts from being executed in the browser.
  • Use both server-side and client-side checks.
  • Prevent SQL injection by using parameterized queries or ORM (Object Relational Mapping) systems that automatically sanitize input.

So, if you are careful, you can avoid this security oversight while deploying the web app.

2.Rushed DNS Configurations

A web app obviously requires a good DNS configuration. DNS stands for Domain Name System. DNS is responsible for internet navigation. All devices on the internet use an IP address to identify themselves. This includes website servers, computers, smartphones, and other edge devices.

However, developers often rush through DNS setup when deploying a web app, assuming it’s just a “set-and-forget” task. In reality, improper DNS configuration can cause major issues, such as:

  • Slow website load times that lead to high bounce rates.
  • Security loopholes that can lead to DNS cache poisoning attacks
  • Complete site inaccessibility due to a mismatched IP address and domain name.

If records like A, AAAA, CNAME, or MX aren’t correctly assigned, your domain might point to the wrong server or fail to resolve altogether, which can drive away users and hurt your credibility.

How to Fix it?

You can fix this mistake by being thorough about their DNS configuration. Double-checking your domain's DNS records before and after deployment is one approach. Using a DNS record lookup tool allows you to quickly verify whether your domain is pointing to the right server. You can also check whether other critical records — like SPF, DKIM, or CNAME entries — are properly configured.

This simple habit can save hours of debugging and ensure your web app is always reachable to the end user.

3.Overusing Plugins and Excessive API Calls

A web application usually does not do all parts of its functions on its own server. The presence of APIs and plugins allows websites to use other services to do specialized tasks.

For example, a web developer can create an analysis app that pulls data via an API from another app that specializes in reporting. Inexperienced web devs can make an easy mistake here, which is the overuse of APIs and plugins.

All the API calls have a cost. They take time to make a request to the host service, and the response also takes time. To the end user, that appears as extra loading time.

Too many API calls can stack and result in huge loading times, which makes your web app appear extremely clunky and slow.

How to Fix It?

You can fix these issues by doing the following things.

  • Caching API responses. This approach works when you are using an API call for the same data.
  • Lazy Loading and Conditional Fetching. These are techniques that make your app load data only when it is absolutely required. This prevents your whole web app from appearing slow and clunky.
  • Limiting the use of APIs and implementing 3rd party functionality natively. This is a difficult approach, but it is way better in the long run.

So, try applying them to make the app perform better.

4.Poor Documentation

Documentation of your web app is necessary for troubleshooting and maintenance of your app. In a big company, many developers will work on a single web app, and without documentation, they can’t understand the parts made by others before them.

Unfortunately, many web devs make the erroneous judgment to delay or outright ignore proper documentation to save time. Usually, in such scenarios, the crunch and tight deadlines also result in a lot of spaghetti code, which is borderline impossible to comprehend.

This makes your web app unmaintainable in the long run.

How to Fix it?

Unfortunately, there is really no way to fix it. You have to create proper documentation as you code along. That’s the only way to avoid this problem before deployment.

5.Bad QA and Testing Procedures

Quality assurance is a vital part of any project. Without proper quality assurance, you cannot deploy a web app. Skipping this step often results in broken functionality, security loopholes, and a poor user experience. Even the most well-designed application can fall apart if it's not thoroughly tested before launch.

QA isn't just about making sure the app works — it’s about ensuring that it performs reliably across different devices, browsers, and network conditions. Rushed or incomplete testing can leave critical bugs unnoticed, which can cause downtime, frustrate users, and even compromise sensitive data.

A strong QA process includes:

  • unit tests,
  • integration tests,
  • end-to-end testing,

And real-world user simulations. After doing all that, you can confidently deploy your app knowing it is stable and secure.

How to Fix it?

To fix bad QA, look into the following.

  • Create clear test cases. Define the proper use case, explore what actions a user might take, and protect against unexpected actions.
  • Automate where you can. Many QA tasks can be automated, which means you can save time and money.
  • Check the app across different environments to see if it works properly.

These are some of the things you can do to ensure that your QA process is not terrible.

Conclusion

So, there you have it, five mistakes developers make when deploying web apps. By fixing these mistakes, you can ensure that your web app deploys successfully and effectively.