email-blast

Email Blast

Send one-off emails to Gumroad creators by executing Ruby inline against the production console. No PR, no deploy, no service class needed.

Prerequisites

• Production console access configured via the gumroad-prod-console skill (see its SKILL.md for setup)
• Metabase API key (in 1Password: "Metabase (Gumroad)" → "API Key")

All production Ruby execution in this skill goes through .claude/skills/gumroad-prod-console/scripts/prod_query.sh. That script targets the read replica for MySQL, which is sufficient here — User.alive.not_suspended...find_each is a read, and deliver_later + $redis.set hit Redis, not MySQL. Do not add any MySQL-write operations to blast scripts.

Workflow

1. Clarify the request

From the human's request, extract:

• Who — recipient criteria (e.g. "all active creators", "creators who earned > $1000")
• What — the message to send (subject + body)
• Reply-to — default support@gumroad.com

2. Draft the email

Write a subject and HTML body:

• Simple HTML only: <p> tags, <a> links
• Sign off: <p>— The Gumroad Team</p>
• No <ul>/<li> (renders poorly). Use <p>• Item</p> for bullets.
• Keep it short and direct
• Always use from: "Gumroad <gumroad@creators.gumroad.com>" and sender_domain: :creators
• The OneOffMailer template renders the subject as an <h2> heading at the top automatically

Present the draft for human approval before proceeding.

3. Count recipients via Metabase

Build a SQL query and validate the count:

METABASE_KEY=$(op item get "Metabase (Gumroad)" --vault Gumclaw --fields "API Key" --reveal)
curl -s -X POST "https://gumroad.metabaseapp.com/api/dataset" \
  -H "Content-Type: application/json" \
  -H "X-Metabase-Session: $METABASE_KEY" \
  -d '{
    "database": 2,
    "type": "native",
    "native": { "query": "SELECT COUNT(*) FROM users WHERE deleted_at IS NULL AND is_suspended = 0 AND ..." }
  }' | python3 -c "import json,sys; print(json.load(sys.stdin)['data']['rows'][0][0])"

Always filter: deleted_at IS NULL AND is_suspended = 0 (alive, not suspended).

Show the count to the human before executing.

4. Dry run (preview)

Generate a script that sends to just 1-2 test recipients first. Run via prod_query.sh:

cat << 'RUBY' | .claude/skills/gumroad-prod-console/scripts/prod_query.sh
test_user = User.find_by(email: "sahil@gumroad.com")
OneOffMailer.email(
  email: test_user.form_email,
  from: "Gumroad <gumroad@creators.gumroad.com>",
  subject: "SUBJECT HERE",
  body: <<~HTML,
    <p>Body here.</p>
    <p>— The Gumroad Team</p>
  HTML
  reply_to: "support@gumroad.com",
  sender_domain: :creators
).deliver_later(queue: "low")
puts "Test email enqueued to #{test_user.form_email}"
RUBY

Wait for human confirmation that the test email looks good before proceeding.

5. Execute the blast

Generate the full script with Redis checkpointing for resumability:

cat << 'RUBY' | .claude/skills/gumroad-prod-console/scripts/prod_query.sh
redis_key = "email_blast_DESCRIPTIVE_KEY_last_user_id"
last_processed_id = $redis.get(redis_key).to_i
count = 0

User.alive.not_suspended.where("id > ?", last_processed_id).where(CRITERIA).find_each(batch_size: 500) do |user|
  next if user.form_email.blank?

  OneOffMailer.email(
    email: user.form_email,
    from: "Gumroad <gumroad@creators.gumroad.com>",
    subject: "SUBJECT",
    body: <<~HTML,
      <p>Body here.</p>
      <p>— The Gumroad Team</p>
    HTML
    reply_to: "support@gumroad.com",
    sender_domain: :creators
  ).deliver_later(queue: "low")

  $redis.set(redis_key, user.id)
  count += 1
  Rails.logger.info "Enqueued email for user #{user.id} (#{count} total)" if count % 100 == 0
end

puts "Done. Enqueued #{count} emails."
RUBY

6. Resume / Reset

• Resume (if interrupted): Just re-run the same script. Redis checkpoint skips already-processed users.
• Reset (to re-send): Delete the Redis key first:

  echo '$redis.del("email_blast_DESCRIPTIVE_KEY_last_user_id")' | .claude/skills/gumroad-prod-console/scripts/prod_query.sh
  

Safety Rules

1. Always get human approval on subject, body, and recipient count before executing
2. Always send a dry-run to a test recipient first (sahil@gumroad.com or the requester)
3. Always use Redis checkpointing — blasts can be interrupted and resumed
4. Always use deliver_later(queue: "low") — never deliver_now (would block the runner)
5. Always filter alive.not_suspended and form_email.present?
6. Never send from hi@customers.gumroad.com — that's for transactional emails only
7. Log progress so you can verify emails are being enqueued

Key References

• OneOffMailer: app/mailers/one_off_mailer.rb
• Example service: app/services/onetime/notify_sellers_about_legacy_fee_migration.rb
• form_email: The user's preferred contact email (may differ from login email)
• Sender domains: :creators → creators.gumroad.com, default → customers.gumroad.com