Once and only once Try it

limiter = RateLimit::Limiter.new(apikey: "ACCT_ID|APIKEY")

# only need to do this on startup
limiter.upsert_limit("send_email", 1, RateLimIt::INFINITE)

# only pass the check once per user
if limiter.check?("send_email:welcome_email:user12312")
  really_send_the_email()
end