Gmail Thread Aging + Stripe Invoice Overdue: Unified AR Follow-Up Digest to Slack via Zapier

AR follow-up in early-stage SaaS is almost always manual and inconsistent. The actual workflow: someone checks Stripe for overdue invoices, searches Gmail for the last email to that customer, then Slacks the account owner. That's 20 minutes per account — and it gets skipped entirely when the team is heads-down. The result is invoices sitting overdue for 30+ days because nobody saw them.

Stripe's `/v1/invoices` endpoint with `status=open` and a `due_date` range gives you every overdue invoice with customer email. Gmail's API — accessed through Zapier's 'Find Email' action — pulls the most recent thread with that customer and returns its date. The gap between invoice due date and last email date tells you exactly how cold the relationship is. That's the number that drives action.

Zapier is the right choice here specifically because non-technical ops people need to own this, not engineers. The Stripe and Gmail integrations are OAuth — zero API configuration. The real tradeoff is cost: multi-step Zaps with filtering require a paid plan (~$49/month). If you're comfortable with n8n or Pipedream, use those for the same logic at lower cost.

The Slack digest format is not an afterthought. Don't dump 20 overdue invoices into a channel. Rank by amount descending, show only the top 10, and always include the 'days since last email' column. An invoice that's 14 days overdue with a Gmail thread from 12 days ago is a warm follow-up. The same invoice with a thread from 45 days ago is a potential churn event. Those are different situations — the digest has to show the difference. Skip this entire workflow if your invoicing runs through Chargebee or Recurly and those tools already send AR reminders — you'll confuse customers with duplicate outreach. Also skip if you have a dedicated AR person working a daily collections queue; this is built for ops generalists who own AR as one of many jobs.