I will demo to you VoteSpin's campaign donation engine powered by PayPal. I borrowed the original PayPal logic from Cuban Links blog (see URL below) http://cubanlinks.org/articles/2005/8/3/ruby-on-rails-paypal-ipn-code-example My code is below: if @request.method == :post ## use the POSTed information to create a call back URL to PayPal @query = 'cmd=_notify-validate' @request.params.each_pair {|key, value| @query = @query + '&' + key + '=' + value.first if key != 'register/pay_pal_ipn.html/pay_pal_ipn' } ##http = Net::HTTP.start(PAYPAL_URL, 80) http = Net::HTTP.start("www.paypal.com", 80) response = http.post('/cgi-bin/webscr', @query) http.finish # PayPal values item_name = @params[:item_name] item_number = @params[:item_number] payment_status = @params[:payment_status] payment_amount = @params[:mc_gross] payment_currency = @params[:mc_currency] txn_id = @params[:txn_id] receiver_email = @params[:receiver_email] payer_email = @params[:payer_email] #if response if response.body.chomp == "VERIFIED" ## check the payment status if payment_status == "Completed" # check to see if the txn_id already exists @donation = Donation.find(item_number) if @donation if @donation.transamount == 0 @paypalipn = item_name + "-" + item_number + "-" + payment_status + "-" + payment_amount + "-" + payment_currency + "-" + txn_id + "-" + receiver_email + "-" + txn_id + "-" + payer_email if @donation.update_attributes(:transamount => payment_amount, :paypalipn => @paypalipn) @voter = Voter.find(:first, :conditions => [ "id = ?", @donation.voter_id]) @message = "Hi " + @voter.userid.capitalize + ",\r\n\r\nYou have just received a $" + payment_amount + " donation at VoteSpin (http://www.votespin.com/votespin/signin?deeplink=/donations/list). \r\n\r\nRegards,\r\nTeam VoteSpin" Notifier::deliver_email_voter(@voter.email, 'info@votespin.com', 'Donation Received at VoteSpin!', @message) render :layout => false end end end end end