4 hours ago (at 15:53:08UTC today), I closed this question over on CodeGolf.SE. We've discovered before that it's possible to answer a few minutes "under the line" due to caching before, simply by not refreshing the page. For example, this answer was posted at 15:59:08UTC.

However, a few minutes ago, somehow, this answer was posted, 4 hours after closing, which lead to general confusion in our chat room, along with this thought:

if the closure check is client-side could one theoretically just disable it an post an answer to an already-closed challenge? and if it isn't cilent-side, how is Neil able to do that if it should be closed server-side already o.O

by hyper-neutrino.

A few minutes of caching isn't much of an issue, hours of caching potentially is.

Is this a problem?

  • 5
    ^ meta.stackexchange.com/questions/79434/… they beat it by ~ 2 minutes.
    – Kevin B
    Apr 22, 2021 at 20:07
  • Thoughts of rogue userscipts allowing answers after closure are flashing through my head now... I'm inclined to imagine that it still wouldn't be much of an issue though, even if it was moderately common. It's very detectable, and repercussions could be doled out to user(s) who started purposely abusing it for whatever reason.
    – zcoop98
    Apr 22, 2021 at 20:20
  • 1
    If it actually requires the answer to have already been in the process of being written, the potential of this being reliably abused is... extremely small, but it's unclear if that restriction is client-side or server-side.
    – Kevin B
    Apr 22, 2021 at 20:22
  • With JQuery and a console, literally anything is possible.
    – Ollie
    Apr 22, 2021 at 20:25
  • 2
    Three SEDE queries for those wanting numbers on the frequency of these: #1 for all post-closure answers on a site (sans obvious merges), #2 for grouping such posts by author, and #3 for grabbing such posts for a specific user. The champion on SO has 149 post closure answers (of their 13k+ answers lol).
    – zcoop98
    Apr 22, 2021 at 21:54
  • 1
    This is not a bug. The server has a deliberate “grace window” of several hours in which answers are still accepted. Apr 25, 2021 at 3:25

1 Answer 1


It's still possible to answer a closed question within 4 hours. That user just squeaked in. Here's when the question was closed:

enter image description here

And here's when the question was answered:

enter image description here

So they just beat it, about 3 hours 58 minutes after it was closed.

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