Why the job you found is already filled
The job you found is already filled because the page you found it on does not know that yet, and has no way to find out. An aggregator holds a copy of a listing, not the listing itself, and copies do not update themselves when the original changes.
A copy has no line back to the source
Think about what actually happens when an employer posts a role. It goes up on their own board, on Greenhouse or Lever or Ashby, under their control. An aggregator that wants to show that listing has to get it somehow: a scraped page, a data feed, a partnership arrangement. Whatever the method, the aggregator now has its own record of a job that lives on someone else's system.
That record does not have a live connection back to the employer. It is a snapshot, taken at whatever moment the aggregator last pulled data, and it stays exactly as it was pulled until the aggregator pulls again. If the employer closes the req an hour after that pull, the aggregator's copy does not know. It will keep showing the job, with an apply button that may or may not still lead anywhere useful, until the next refresh cycle happens to catch the change.
Refresh cycles are not the same as reality
Even a well run aggregator refreshes on a schedule, not in real time. Between refreshes, every closed role is invisible to the aggregator and visible to you. You have no way to tell, just by looking at the page, whether you are looking at a job posted this morning or a job that closed last week and simply has not been swept yet.
This is worse than it sounds, because the roles most likely to sit stale are often the ones that looked most attractive. A posting that draws a strong pool of applicants tends to close faster than one that struggles to attract anyone. So the gap between "still shown" and "still open" is not evenly distributed. It skews toward exactly the jobs you would most want to apply to quickly, which is also exactly when applying to a closed role wastes the most of your time.
The employer's own board does not have this lag
An employer's own careers page does not have a refresh cycle, because there is nothing to refresh. The page is the source. When a recruiter closes a requisition, the same system that displayed the listing removes it, because it is one system, not two. There is no second copy sitting somewhere else that has to catch up.
That is the whole case for going to the company's real careers page instead of an aggregator's version of the same role, and for treating company job boards as the more reliable source than aggregators as a general rule, not just a preference. It is not that aggregators are badly built. It is that the thing they are built to do, mirror a listing that lives somewhere else, has an unavoidable delay baked into it.
What this costs you if you do not notice
Applying to a closed role is not neutral. You still spend the time reading the description, tailoring your resume, maybe drafting a note about why you are a fit. Some of that effort is reusable elsewhere, but a chunk of it is specific to a job that no longer exists. Worse, a certain number of these applications will simply vanish. You submit through a form that still technically accepts submissions, and nothing on the other end is reading it, because the req is closed and nobody is monitoring that inbox anymore.
That silence is easy to misread as rejection, or as your application being bad, when the actual explanation is much less personal: you applied to a job that was not there anymore. If you want to know what that silence usually does and does not mean more broadly, being ghosted after applying covers the other common reasons an application disappears without a response, closed listings being only one of them.
What a copy usually looks like
A few signals are worth checking before you invest real time. Look at the web address itself: does it belong to the employer's own domain and their own applicant system, or does it sit on a separate platform that aggregates postings from many employers at once. Look at whether the apply button keeps you on that same system or redirects you somewhere else entirely, since a redirect straight to the employer's own applicant tracker is a good sign you have reached the source rather than a copy. Look for any indication of how recently the posting was touched, though treat this loosely, since a copy can carry a timestamp from whenever it was scraped rather than whenever the role was actually last updated by the employer.
None of these checks are foolproof on their own. Together, they are usually enough to tell you, in under a minute, whether you are looking at a page the employer controls directly or a page that merely reflects what the employer's page looked like at some earlier point.
What to do with this
You cannot always tell, from a single listing, whether you are on the source or a copy. But you can develop a habit: when a role looks strong, before you invest real time in the application, check whether the URL you are on belongs to the employer's own domain and their own applicant system. If it does, you are looking at the source, and a closed role simply will not be there. If it does not, treat the listing as provisional until you have confirmed it still exists somewhere the employer controls directly.
That one habit will not catch every stale posting, but it removes the single biggest source of wasted applications in a search: time spent tailoring a resume for a job that closed before you opened the page.
iapplyai.app sweeps a curated graph of confirmed employer boards rather than aggregator copies, so the listings it scores against your resume are the ones still live on the employer's own system.
