Launching an application is one of the most important moments for any startup. After months of development, product validation, UX design, and testing, the moment finally arrives to put it in the hands of users.
However, there's one aspect that often gets pushed aside in favor of more visible priorities like features, growth, or customer acquisition: security.
The truth is attackers don't wait for a company to become a unicorn before trying to compromise it. An application starts receiving automated scanning and attack attempts practically from the moment it's published on the internet.
If you're building an application or planning to launch one soon, here are some of the security aspects you should review before deploying it.
1. Your application is already being attacked
There's a fairly common belief that cybercriminals only target large companies. In reality, most current attacks are completely automated.
Thousands of bots crawl the internet 24 hours a day looking for opportunities. They're not chasing a specific company; they're looking for mistakes, insecure configurations, or exposed services they can take advantage of.
Among the most common targets are:
- APIs exposed to the internet.
- Leaked credentials.
- Misconfigurations.
- Vulnerable software versions.
- Unprotected accessible services.
This means a freshly launched application can start receiving scanning attempts even before it gets its first users.
That's why, when we talk about security, the question isn't whether someone will try to attack your application. The question is whether they'll find something that lets them do it.
2. Login isn't enough
Many teams feel reassured once they implement a login screen. After all, if every user has an account and a password, the problem would seem to be solved.
The reality is quite different.
Authentication is only part of the problem. A secure application must also correctly control what each user can do once they log in.
For example:
- Can users only access their own information?
- Are there differentiated permissions between admins and regular users?
- Is password recovery secure?
- Are sessions managed correctly?
Many security breaches happen because an attacker doesn't need to break a password. They simply exploit flaws in the authorization logic to access information or functionality they shouldn't have.
Security isn't just about verifying who gets in, it's also about controlling what each person can do once they're inside.
3. The API matters as much as the frontend
When we think about an application, we tend to focus on what users see: the design, the navigation experience, the forms, or the features.
But behind every screen there's an API that processes requests, queries databases, and runs the business logic.
From an attacker's perspective, the interface is just a surface layer. The real target is usually the API, since that's where the data and critical functionality of the application live.
A poorly protected API can expose risks such as:
- Access to sensitive information.
- Manipulation of data or transactions.
- Exposure of internal endpoints.
- Flaws in permission and role validation.
Many organizations invest time and resources into improving the user experience but neglect the security controls running behind the scenes. As a result, an application can look modern and work perfectly while still holding vulnerabilities that let an attacker access information that should never be available.
An application's security doesn't depend only on what happens in the frontend. It also depends on how well protected the infrastructure behind it is.
4. Data is your biggest responsibility
Every time a user creates an account, makes a purchase, or fills out a form, they're placing their trust in your organization.
Depending on the type of application, you might be storing emails, phone numbers, addresses, financial information, or sensitive documentation. All of that information has value for the business, but also for an attacker.
A security breach isn't just a technical problem. It can also lead to customer loss, reputational damage, and regulatory consequences depending on the industry and the type of data compromised.
Trust takes years to build and can be lost in a matter of hours.
That's why data protection shouldn't be seen only as a legal requirement or a technical best practice. It's a strategic decision that directly impacts the reputation and sustainability of the business.
5. A vulnerability can cost more than a pentest
In the early stages of development, fixing a vulnerability usually takes a few hours of work. The team knows the product, the code is recent, and changes can be implemented quickly.
After an incident, the picture changes completely.
It's no longer just about fixing a flaw. You also need to investigate what happened, determine the scope of the problem, and manage the consequences.
Among the most common costs are:
- Customer loss.
- Reputational damage.
- Regulatory fines or sanctions.
- Additional development time.
- Operational disruptions.
Most companies don't suffer from the cost of a vulnerability. They suffer from the cost of discovering it too late.
That's why the most mature organizations incorporate security assessments before launching new features or critical releases. Not because they expect to be attacked, but because they understand that prevention is far more efficient than reacting.
Before deploying an app, ask yourself this question
Before launching an application, most teams ask themselves whether the product works correctly. That's an important question, but there's another one just as relevant:
Am I sure my application is as secure as it is functional?
Security shouldn't show up only when the first customers arrive or when the first incident happens. It should be part of the process from the start, growing alongside the product at every stage, because a successful application isn't just one that works, it's one that users can trust.
About Krill Security
At Krill Security, we help startups and companies identify vulnerabilities before they can be exploited through Penetration Testing, offensive security, and continuous attack simulation services.
Our goal is for organizations to launch, grow, and innovate with the confidence that their technology is ready to face threats.