A version of this question comes up often from people building quickly, adding features week over week: do I need to check security on every single one of these, or is it enough to do one real pass right before I open things up to actual users?
The honest answer: it depends what the feature touches
Not every feature carries the same risk. A change to how a button is styled, or how a page is laid out, doesn't need its own security review. A feature that introduces a new way to access, upload, share, or expose data does, because that's exactly where the categories of issue I write about most often tend to show up: a new sharing feature that skips an ownership check, a new upload path with no validation, a new API endpoint that doesn't verify who's calling it.
A useful rule of thumb
If a feature touches user data, changes what's shared with whom, adds a new way to upload or fetch something, or adds a new API route, it's worth a quick, targeted look specifically at that feature before it ships, not a full audit, just checking the specific new surface area it introduces. If it doesn't touch any of that, one broader pre-launch check is genuinely enough.
Why waiting until launch alone is risky
The risk with checking only once, right before launch, is that by then a real number of features have already accumulated, each one a potential place something was missed, and a single pass at the end has to catch all of them at once. Checking the higher-risk features as they're built spreads that work out and catches issues while the context of what changed is still fresh, rather than all at once against a much larger surface.
What this looks like in practice
- Low-risk changes (styling, copy, layout): no dedicated check needed.
- Medium-risk changes (a new form, a new page): worth a quick manual look at that specific feature.
- High-risk changes (sharing, uploads, new API routes, anything touching another user's data): worth a targeted check before that feature ships, not after.
- Before opening up to real users regardless: one broader pass across the whole app, even if individual features were already checked along the way.
The short version: not every feature, but the ones that change who can see or touch what, yes, checked as you go rather than saved up for one big pass at the end.