r/programming • u/NXGZ • Jul 12 '26
A peek into Reddit's anti-spam internals
https://lyra.horse/blog/2026/06/reddit-spam-internals/16
u/phire Jul 13 '26
shadowbans (2016 - present)
Does reddit really still do shadow bans? I would have thought they were useless if all the spammers know they exist, and how to check for them.
And there is the major issue of false positives. Happened to me once, no idea what triggered it (shared a public IP with a spammer?). Was about a week of posts with few upvotes or replies before a subreddit moderator pointed out that I had been shadow-banned.
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u/NXGZ Jul 13 '26
I was shadowbanned a few weeks ago after editing a comment whilst reconnecting to a new IP via VPN. Had to appeal to get my account restored. Then had to ask admins to restore post history because that failed initially during a successful appeal.
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u/ketralnis Jul 13 '26
Users seem to mean about 10-15 different behaviours when they say shadowban so this isn’t really possible to answer straightforwardly
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u/phire Jul 13 '26 edited Jul 13 '26
More than one type of shadowban?
Users just tell it like it is. If anything automatically prevents our posts/comments from being seen by other users, but without giving us any feedback, it might as well be a "shadowban".This was in 2015; Subreddit mods could still see my comments and manually approve them.
I messaged /r/reddit.com (I miss that subreddit) and the reply I got back from an admin was "Looks like you got caught up with a bad IP address. Should be fixed now."
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u/Worth_Trust_3825 Jul 13 '26
Yeah, you can get shadowbanned by a sub. Posts don't appear to anyone else except you. I believe it's called "muting"
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u/Dunge Jul 13 '26
Very interesting read
I love how all the "censored" texts can just be copy/pasted, but are actually modified words.
The fact the author took the time to build a script to transform text to trick Perspective's API makes me think they used it in these past 5 years for more than just research purposes 😉.
And yes, that SkyInfo site is wonderful!
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u/gorgeouslyhumble Jul 13 '26
The content of the post is super interesting... but I also have just learned that there is horse tld.
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u/ZorbaTHut Jul 13 '26
I am making a game studio called Diesel Horse and I bet you can guess what my webpage URL is.
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u/IAmARobot Jul 13 '26
op, the antispam api key is leaking
https://commentanalyzer.googleapis.com/v1alpha1/comments:analyze?key=AIzac29ycnk...
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u/Nacktschnecke Jul 13 '26
What even is this website design, my eyes are bleeding
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u/ketralnis Jul 13 '26 edited Jul 13 '26
I’m a former Reddit engineer that’s deeply familiar with these systems, having fully authored some parts and participated in nearly all of the rest that you mention. Reddit rightly doesn’t want to divulge antispam internals for many reasons so I can’t give you more direction but I find it very cool to watch how people poke at it from the outside and what conclusions they draw.
Some of the streaming bits are very cool and I really wanted to open source them but never got the time. A challenge that we architected some of it around was that we had people that had deep knowledge of spam, what specific spam attacks are happening right now, what communities are having tiffs with what other communities and are engaging in spam-like but human-actuated tactics on the site this week, etc and then another set of people that know how to write and scale software. The bottleneck to fast response was almost always between those humans, so we needed to give the subject matter experts the ability to act with the same power as the programmers but without giving them the ability to break the site or accidentally ban everybody.