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The Complete Rate-Limiting Guide

I've seen a number of time delay notifications on the sites. E.g.:

you can only comment every x seconds

What are all the situations that have timing delays? After we are proven to not be bots, why are repeated delays necessary?


4 Answers 4


You can prove that you aren't a bot now, but you can't prove that you aren't a bot five minutes from now.

  • 4
    Are you suggesting that someone is replacing users with bots, and not telling them that the are replacements? If a bot doesn't know it's a bot, and can solve clever mangled-word puzzles, is it still a bot?
    – Welbog
    Oct 19, 2009 at 13:18
  • 2
    Just reuse the cookie from the browser and plug it to a spam bot. How easy is that to spam/DoS without the delay.
    – nhahtdh
    Jul 5, 2012 at 3:21

It seems no one else is willing to do this, so here goes...

In all situations where CAPTCHAs are involved, for users with at least 200 reputation, once a CAPTCHA is solved, another one will not appear for the next five minutes. Exceeding 40 minutes to submit a question, answer, or edit would previously trigger a CAPTCHA, but this has since been removed.

Asking questions

There is a limit of 50 questions within a rolling 30-day period and 6 questions within a rolling 24-hour period, including any questions asked within these periods later deleted; a question can only be posted once every 30 seconds, and users with less than 125 reputation are limited to one question every 20 minutes (source). Additionally, attempting to submit a question more than once every 60 seconds (for users with less than 10,000 reputation) or faster than 5 seconds after starting to ask will trigger a CAPTCHA.

Answering questions

Users with less than 125 reputation are limited to one answer every three minutes and cannot answer their own question within 8 hours of posting their question. There is no limit for users with at least 125 reputation, except that attempting to submit an answer more than once every 60 seconds (20 seconds for 10K users) or faster than 5 seconds after starting to answer will trigger a CAPTCHA.

Accepting answers

Users must wait 15 minutes after asking a question to accept an answer and must wait 48 hours after the question was asked to accept their own answer.

Voting on posts

Normal users are limited to 30 votes (up or down) per day for all posts, plus 10 votes per day for questions only; the question-only votes cannot be used once the user has casted 25 votes on answers (source). Downvotes on posts that are later deleted do not count toward this limit.


Normal users are limited to 6 searches per minute. ♦Moderators are limited to 12 searches per minute. Source

Comments and comment votes

Users are limited to posting one comment every 5 seconds. Voting on comments, including deletion, is limited to once every 5 seconds. Fetching additional comments is limited to once every 2 seconds.

Editing and suggesting edits

Users are limited to editing five of their own posts per day. Unregistered users cannot suggest edits on posts less than 10 minutes old. Attempting to submit an edit more than once every 30 seconds (10 seconds for 10K users) or faster than 5 seconds after starting an edit will trigger a CAPTCHA.

Deleting posts

Users are limited to deleting five of their own posts per day. Source

Showing upvote/downvote totals (1K privilege)

Users are limited to fetching upvote/downvote totals once per second. Source

Changing username

Users are limited to changing their username once every 30 days; users with accounts less than 2 days old may freely change their name. Source

  • Chat search as well (I dunno the exact params that trigger it--it's sort of variable in the timeouts it gives) Jul 1, 2012 at 3:12

They're not just there to stop bots, but also anti-social users.

  • 1
    You stop anti-social users by preventing them from contributing too much?
    – TheTXI
    Oct 19, 2009 at 13:22
  • 2
    Stop is a bit strong... limit might be better
    – Greg
    Oct 19, 2009 at 13:25
  • 1
    I'm starting to think you're using a different definition of "anti-social" than the rest of the world.
    – TheTXI
    Oct 19, 2009 at 13:30
  • 10
    Whoever invented the "inconvenience the many to stop the few" school of design deserves a swift kick to the crotch. Oct 19, 2009 at 13:31
  • And anti-social users are known to mass-upvote comments?
    – innaM
    Oct 19, 2009 at 13:32
  • @Manni more mass-downvote but yes, sometimes mass upvote
    – Greg
    Oct 19, 2009 at 13:35
  • @TheTXI I'm using it the British way... sorry
    – Greg
    Oct 19, 2009 at 13:35
  • I don't understand the downvotes... that's what they're for. I'm not saying I agree that they should be there (because I don't - I'd love to see them removed, at least once you hit a certain rep)
    – Greg
    Oct 19, 2009 at 13:36
  • @Greg: The down votes are because people feel you are wrong. And you are.
    Oct 19, 2009 at 14:11
  • @Rich B Thanks for clearing that up
    – Greg
    Oct 19, 2009 at 14:37
  • @Greg: No problem. I aim to please.
    Oct 19, 2009 at 15:04
  • 1
    We have a saying over here that says "I aimed to the belfry, but hit the priest."
    – perbert
    Oct 19, 2009 at 16:52
  • 1
    @voyager: Are you saying Rich B is a priest? I'm all confused.
    – mmyers
    Oct 19, 2009 at 18:58
  • @mmyers: Well if it is true that "You are what you eat", then yes.
    Oct 19, 2009 at 19:33
  • Accepting your own answers. (24 hours). Aka "The Masturbation Clause"
  • Accepting any answer (I think its 5 minutes). Aka "Fools Rush In"
  • Some references would be helpful here. I think it't 15 minutes for accepting answers, but I don't want to go link-hunting right now. Sep 28, 2011 at 9:03
  • Well I discovered the "Masturbation Clause" on my own, you can try it yourself too!
    – bobobobo
    Sep 29, 2011 at 15:25
  • 1
    Hmm, well, in this question it says 48 hours for self-accepts and 15 minutes for other accepts. Sep 29, 2011 at 15:44

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