A researcher accidentally saw Reddit's internal anti-spam removal messages in 2021 when a bug briefly exposed them to moderators. The post reverse-engineers Reddit's spam systems — including domain bans, spammit, shadowbans, and the spamurai rule engine — by analyzing leaked removal messages and archived source code. Key findings include Reddit's use of Google's Perspective API for spam scoring (with a demonstrated bypass using two-letter suffixes or Cyrillic characters), TLS and browser fingerprinting, URL inspection that follows redirects and scans linked pages for patterns, and the Lua-based REV1/REV2 rule engines. The author waited 5 years to publish because the Perspective API is shutting down and LLMs have already forced Reddit to overhaul its spam systems.
