I treat security as a constraint from day one. Skipping the basics leads to data leaks, weak permissions, or injection attacks.
Strong authentication
I rely on proven standards: JWTs signed with a rotating key, OAuth2 when needed, strict token lifetimes. Refresh flows are cautious, scopes stay minimal, and sessions are revoked cleanly. Secrets stay in a vault (Vault, Google Secret Manager, or AWS Secrets Manager depending on the client), and pipelines verify their presence before deploying.
Input validation
Every request passes through rigorous validation: forms, webhooks, and external callbacks. Inputs have schemas, sizes, and expected value lists. Tools like Zod or Yup let me centralize this logic and give clear errors when something is malformed. That prevents SQL injections, XSS, and surprise loads.
Hardened infrastructure
The infrastructure plan includes network isolation, firewalls, MFA, and automated key rotation. Environments stay separate, privileges stay tight, and backups are encrypted. Audit trails record every access to critical data, and automation jobs run with dedicated service accounts.
A formative experience
Early in my career I worked on cryptography, smart cards, and secure communications. That shaped how I treat authentication, validation, and permissions today. Every new SaaS or e-commerce project inherits that discipline.
Conclusion
Launching fast is great—until an incident hits. By building authentication, validation, and infrastructure safeguards from the first commits, you avoid spending weeks firefighting later on.