Which application fields you can safely skip
The short answer
Skip anything the form does not mark required, unless it clearly helps your case. A cover letter is the cleanest example: across the 20 jobs we measured, it was required on exactly zero, optional on 19, and not even present as a field on the last one. The same pattern holds for most fields that are not on a form's short required list. Optional does not mean pointless. It means the choice is genuinely yours.
Required is not a guess, it is a flag
On systems like Greenhouse, whether a field is required is not something you have to infer from the page layout or a small asterisk you might miss. It is a literal property on the field itself, published in the form's own definition before the page even renders: required: true or required: false, nothing in between. We cover exactly how that gets exposed in Greenhouse shows you the form before you apply. The practical upshot is that you do not need to guess which fields matter. The form already knows, and increasingly, so can you before you start filling it in.
What the cover letter tells you about every other optional field
The clearest test case in our sample was the cover letter attachment. It appeared as a field on 19 of the 20 jobs we measured and was marked optional every one of those 19 times. On the twentieth, the field was not on the form at all. Required, on any of the 20: zero. If an employer genuinely needed a cover letter to consider you, the form would say so, the same way it says so for a resume. It does not. That gap between what applicants often assume is expected and what the form actually enforces is worth sitting with. For the fuller question of whether writing one anyway is worth the time even when it is not required, see do cover letters still matter.
The mistake that goes the other direction
Here is the part that is easy to miss: optional does not mean irrelevant, and a field being present in the samples you happen to see does not mean it is always there. We learned this one directly. One employer's postings disappeared entirely from a set of results we were generating, and the cause turned out to be a single optional field that was simply absent from that employer's form. A parser downstream had assumed the field would always be present and broke silently when it was not, taking every posting from that employer down with it.
The lesson generalizes past parsers. Sampling proves presence. It never proves requiredness, and it never proves universality either. Seeing a field on ten job postings in a row tells you it is common. It does not tell you it will be there on the eleventh, and it does not tell you the form will treat it the same way twice. Treat every field, on every new application, as its own small check rather than an assumption carried over from the last one.
The same trap catches applicants, not just the tools reading these forms on their behalf. Fill out five applications in a row that never asked for a desired salary figure, and it is easy to stop expecting the question at all, right up until the sixth form asks for it directly and you are typing a number you have not actually thought through. That particular field is worth deciding on before it appears, and what to type in the desired salary box covers both cases, the one where it is optional and the one where the form will not submit without it. The fix is the same in both cases: read the form in front of you, not the pattern from the last several.
Not all optional fields are optional in the same way
Two fields can both be marked optional and still deserve completely different treatment. A demographic question is optional in the sense that skipping it has no bearing on your candidacy at all, since that data is handled separately from the file a hiring manager reviews. A portfolio link is optional in a different sense: nobody is penalized for leaving it blank, but for a role where your work speaks for itself, filling it in can genuinely help your case. Lumping every optional field into a single skip-it-or-not decision misses that distinction. The useful question is not only whether a field is required, but what filling it in would actually do for this specific application.
A working rule for the next form you open
If a field is marked required, fill it in. There is no strategy in leaving it blank; the form will not let you submit until you do. If it is marked optional, ask what it actually does for you before deciding to skip it. A portfolio link is optional and often genuinely useful for design or engineering roles where the work speaks for itself. A cover letter is optional and, per the numbers above, rarely the deciding factor. An EEO or demographic question is optional in the sense that declining to answer is always one of the choices, and declining costs you nothing. None of these deserve the same decision. They deserve the same five seconds of actually reading what the field is asking before you either fill it in or move past it.
Why this is worth thirty extra seconds per application
Skimming past an optional field without reading it is how people either waste time on fields that do not matter or, worse, skip a field that would have quietly strengthened their application for almost no cost. The required flag tells you what you cannot avoid. It does not tell you what is worth doing anyway, and that second judgment is the one actually worth your attention once the mandatory parts are handled.
For the complete picture of what a typical application form asks across its required and optional fields together, start with what ATS application forms actually ask for.
iapplyai.app reads each employer's actual required flags before it prepares your application, so it never guesses at what a form expects and never pads an application with fields that were never going to matter.
