Build a public WhatsApp API service around customer-scanned numbers.
This platform is invite-based. You create an expiring onboarding link, the customer activates their account, scans their own WhatsApp, gets an API key, and uses your REST endpoints for single and scheduled bulk messages.
Bulk scheduling has built-in guardrails: opt-in confirmation is mandatory, sending is spaced out, quiet hours are enforced, and hourly caps reduce spam behavior. These are platform guardrails, not a guarantee against WhatsApp enforcement.