1. Verdict
Definition of "success"
The portfolio uses two tiers, defined in docs/README.md:
- Tier A (venture): $1M ARR within 36 months, ≥70% gross margin, ≥50% month-12 logo retention.
- Tier B (profitable business, the default target): $20k+ MRR (≈ $250k ARR) within 24 months, profitable, ≥80% gross margin, ≥70% month-3 retention.
The MRR ladder ($1k to $50k by month 24) is in WHAT-TO-DO-AND-AVOID.md.
Probability
All figures are judgment estimates, not computed statistics.
| Version | Tier B | Tier A | Why |
|---|---|---|---|
| As described (SMS, WhatsApp, email, voice; clinics, dentists, therapists, salons; any calendar or practice system) | ~0.5% | <0.5% | No single buyer or channel. Every vertical's booking or practice system already includes reminders, several of them free (10). |
| US clinics and dentists (the Appointment Reminder playbook) | ~1% | <0.5% | Weave ($239M revenue, 39,625 locations in 2025) plus Open Dental's $25/month confirmations. HIPAA BAA and 10DLC costs fall hardest on the smallest vendor. |
| Salons and spas | <0.5% | <0.5% | Fresha, Vagaro, Booksy and Square include reminders. Fresha already sends WhatsApp reminders. |
| Brazil, WhatsApp-first | ~0.5% | <0.5% | Capim gives dentists free, unlimited WhatsApp confirmations. Many local tools. Portuguese-language sales. |
| Indonesia, WhatsApp-first | ~0.5% | <0.5% | Reported utility rate ~$0.025 a message (~18× India). No verified market data. |
| Add-on for one practice system with weak reminders (e.g. WhatsApp for Cliniko) | ~1% | <0.5% | The systems checked all have native reminders (Open Dental, Cliniko, Fresha). Cliniko already has WhatsApp AI add-ons (MIEA, Vascue). |
| Tested wedge: two-way WhatsApp confirmation + slot refill for Indian dental clinics, one city | ~1% (~15 hrs/week) / ~2% (full-time) | <0.5% | Cheap messages, a real phone-confirmation chore, and one-way competitors. But Indian prices mean ~690 clinics for $20k, and EMRs can bundle it any time. |
| Base rate | No verified base rate | — | Nobody publishes the share of new bootstrapped B2B micro-SaaS that reach a given MRR. |
Fundable in current form?
No. And not in the wedge form either. The wedge's realistic ceiling is a few thousand dollars of MRR from small Indian clinics. No investor funds a feature that EMR vendors can switch on.
One-paragraph verdict
The catalog was right to mark this weak, and 2022+ evidence makes it weaker. Appointment Reminder proved in 2010–2016 that one careful founder could build a $12K/month reminder business. That founder sold it in 2016, and the market has since filled in. Weave turned reminders into one line of a $239M patient-communication suite. Open Dental prices confirmations at $25 a month. Salon booking apps send WhatsApp reminders from a prepaid balance. In Brazil, WhatsApp confirmations for dentists are given away free to sell financing. The pain (a no-show rate around one in five, cut by about a quarter with reminders) is real, which is exactly why everyone ships the fix. What's left is a thin gap: two-way WhatsApp confirmations that update the diary and refill cancelled slots, for clinics that have no software or only one-way messages. That gap exists in India, where messages cost a fraction of a rupee and receptionists still phone tomorrow's list. It is worth a 45-day paid test, run by hand, and not worth a year of building. If 10 dental clinics won't pay ₹999 for a pilot, stop.