I've been building SaaS apps with AI and now I want to properly test how secure they are before real users start using them.
I'm not looking for basic advice like use HTTPS, validate inputs, or hide API keys. I want to find actual vulnerabilities, even the ones that are hard to notice.
For example, how do you check if a user can access someone else's data, bypass authentication, abuse APIs, exploit payment logic or find other issues in the backend?
I'm looking for a proper process here, not just a list of tools.
A few things I'd like to know:
- What do you test manually, and how do you go about it?
- Which free tools are actually useful for deep testing?
- Are there any paid tools worth the money for a solo developer?
- Can AI tools like Claude or security agents find serious vulnerabilities in a codebase, or should I not rely on them much?
- How do you test the backend and APIs when you have access to the source code?
- What are some common security issues in AI-generated code that people usually miss?
If you had to test a SaaS from scratch, what would your process look like? Which tools would you use first, and what would you do after that?
I'd prefer advice from people who've actually done application security testing. Even if it's a long process, that's fine. I want to do this properly