What you'll need
Three accounts. Free or close to it.
n8n
Free self-hosted, or n8n Cloud starting $20/mo
SMTP
Gmail, Postmark, SendGrid, or Resend
Survey form
Tally, Typeform, or your own page that POSTs to the webhook
Your CRM
HTTP endpoint to read active customers and tag passives
The math
What this is worth, conservatively
Detractors recovered with timely outreach
~30%
Promoters who give a referral when asked
~50%
Agency with 50 retainer clients, 1 in 5 promoters per quarter
~5 referral asks placed
Cost to run this template forever
~$0/year
Numbers based on industry benchmarks for NPS recovery and referral conversion. Your actual referral close rate is the bigger lever, since one new agency retainer can repay setup time hundreds of times over.