Secure by Default
Security is not a feature you add at the end of a sprint. It is the set of defaults you apply from the first line of code. This course teaches the practical, non-exotic security measures that every production web application needs: HTTPS and TLS, environment variable management, Row Level Security in Supabase, rate limiting, JWT hardening, security headers, and what to do when something goes wrong. No pen-testing, no exotic exploits — just the defensive foundations that prevent 90% of attacks.
What you'll learn
Course outline
Free — no account needed
The Secure by Default Mindset
Deny all, allow explicitly — the design principle that prevents most attacks before they start
HTTPS and TLS — What It Protects and How to Enforce It
Why HTTPS is not optional, what it actually protects, and the two headers that enforce it
Secrets and Environment Variables — The Right Way
The .env pattern, what to expose to the browser, and how to prevent accidental leaks
Full course — $49 one-time
Row Level Security — Database Authorisation at the Data Layer
Supabase RLS: how to ensure users can only access their own data, enforced in the database
Rate Limiting — Brute Force Protection and API Abuse Prevention
How to protect login endpoints, AI calls, and any endpoint that can be abused at scale
Auth Hardening — JWTs, Sessions, and MFA
Making authentication robust: token expiry, rotation, and multi-factor authentication
Security Headers — Configuring the Browser as a Security Layer
CSP, HSTS, X-Frame-Options, and the 10-minute configuration that dramatically reduces attack surface
Logging and Incident Response
Security event logging, anomaly detection, and what to do when something goes wrong
Get the full course
8 lessons — from environment variable basics to production incident response.
Written by the RadarTrek editorial team · Reviewed June 2026
About this course
Building securely is not about memorising a checklist of vulnerabilities — it is about developing a set of default habits and mental models that make secure code the path of least resistance. This secure coding course covers the principles that make security a natural part of how you build rather than an afterthought bolted on at the end: defence in depth, least privilege, input validation at system boundaries, secrets management, dependency management, and row-level security in databases.
This course is for developers who have a working knowledge of web security vulnerabilities and want to establish secure coding habits across their full stack. After completing it you will be able to design systems using defence-in-depth principles, configure Supabase Row Level Security correctly, manage secrets and API keys without accidentally exposing them, audit your dependencies for known vulnerabilities, and set up basic security monitoring.
Frequently asked questions
What is defence in depth?
Defence in depth means layering multiple independent security controls so that an attacker who bypasses one layer still faces others. Applied to web applications: validate input at the API boundary, parameterise database queries regardless, enforce row-level security in the database itself, apply rate limiting at the infrastructure level, and set restrictive permissions on the file system. Each layer is independent — a bug in one does not expose the whole system.
What is the principle of least privilege?
Least privilege means every component should have access to only the minimum resources needed to do its job — and nothing more. Examples: your application's database user should only have SELECT/INSERT/UPDATE on specific tables, not CREATE TABLE or DROP; your API should not have admin access to your cloud provider; third-party integrations should only receive the scopes they need. Limiting access limits blast radius when a component is compromised.
How do I manage API keys and secrets securely?
Secrets (API keys, database connection strings, signing keys) must never be hardcoded in source code or committed to version control. Use environment variables for local development and your deployment platform's secrets manager (Vercel environment variables, AWS Secrets Manager) in production. Add `.env` and `.env.local` to `.gitignore` immediately when starting a project. Rotate any secret that has ever been accidentally committed.
What is Row Level Security and why does it matter?
Row Level Security (RLS) is a database feature that restricts which rows a user can read or modify based on database-level policies. In Supabase, RLS policies ensure that a user who queries the orders table only sees their own orders — not anyone else's. Without RLS, access control relies entirely on your application code, which can be bypassed. RLS provides defence in depth at the database layer.
How do I handle dependencies securely?
Dependencies introduce risk because they contain code you did not write and may have vulnerabilities. Best practices: run `npm audit` or equivalent regularly, use a dependency scanner like Snyk or GitHub Dependabot, keep dependencies updated (especially those in your security critical path like auth libraries), avoid dependencies with no maintenance activity, and minimise the number of dependencies for low-value use cases.