Cybersecurity Essentials Every Web Developer Must Know
SQL injection, XSS, JWT pitfalls, CORS misconfigurations, rate limiting, security headers, and GDPR compliance — a practical security guide for Django and Next.js developers.
Cybersecurity Essentials Every Web Developer Must Know
Security is not a feature you add at the end of a project. It is a discipline you build into every layer — from the database schema to the HTTP response headers. After studying cybersecurity at CK Tedam University and working with production systems at AmaliTech, I have compiled the security fundamentals that every web developer needs to understand, with practical code examples in Django and Next.js.
1. SQL Injection: The Classic That Never Dies
SQL injection remains one of the most exploited vulnerabilities (OWASP A03:2021). It happens when user input is concatenated directly into SQL queries.
Vulnerable code (never do this):
`python
# Django raw query — dangerous
query = "SELECT FROM users WHERE email = '" + user_email + "'"
User.objects.raw(query)
`
Safe code — always use parameterized queries:
`python
# Django ORM — safe by default
user = User.objects.filter(email=user_email).first()
Django raw query with parameters — safe
Django's ORM parameterizes all queries automatically. Only use raw queries when the ORM cannot express what you need, and always use the %s placeholder syntax, never f-strings or concatenation.
2. Cross-Site Scripting (XSS)
XSS allows attackers to inject malicious JavaScript into pages viewed by other users. It is particularly dangerous in applications that display user-generated content.
In Django templates, auto-escaping is on by default:
`html
<-- Safe — Django escapes this automatically -->
{{ user.comment }}
<-- Dangerous — turns off escaping -->
{{ user.comment|safe }}
`
In Next.js / React, JSX auto-escapes too:
`tsx
// Safe
<p>{userComment}</p>
// Dangerous — only use with sanitized HTML
<p dangerouslySetInnerHTML={{ __html: userComment }} />
`