Replace transactional email with messages customers actually open — at the lowest Meta tier rate.

Meta classifies templates by purpose. Utility templates relate to a specific transaction the customer initiated — order confirmations, OTPs, shipping updates, payment receipts, account alerts. Marketing templates promote products or offers. Authentication templates carry OTPs. Pricing differs significantly by category — utility and authentication cost less than marketing, and service replies inside the customer window are free. Meta publishes the current rates and bills them to your own Business Account, so check them there rather than taking any vendor's word for it. WhatsMark's template builder helps you classify correctly so you stay in the cheapest tier for what you're sending.

Different rules per template type. Utility messages tied to an active transaction the customer initiated (placed an order, booked an appointment, requested an OTP for login) don't require a separate marketing opt-in — but the customer must have provided their phone number in the originating flow. Marketing-class follow-ups do require explicit opt-in. WhatsMark tracks consent state per contact and per category so you don't accidentally send a marketing message to a utility-only contact.

Meta charges per 24-hour conversation, not per message. India utility conversations start at ₹0.20 (rate as of May 2026; check Meta's published rate card for current pricing). Inside that 24-hour window, you can send unlimited utility messages — replies and follow-ups don't add cost. WhatsMark adds 0% on top — you pay Meta's rate exactly, billed directly to your Meta Business Account.

Two paths. A connected Shopify or WooCommerce store fires its order and shipping events into WhatsMark natively — no code. For everything else (Razorpay, your own backend), your system calls the WhatsMark REST API — POST the contact phone, template name, and variable values, and the message goes out. WhatsMark doesn't receive arbitrary inbound webhooks from every source; the general pattern is your system calling our API, or a Zapier/Make bridge (Zapier support is on the roadmap).

OTPs go out on Meta's authentication-template tier, the category built for time-critical codes, with a one-tap copy button. WhatsMark's OTP API sends and verifies codes over WhatsApp so your login or checkout isn't dependent on an SMS that may be delayed or never arrive. If a message can't be delivered (the number isn't on WhatsApp, or the business is blocked), your app can fall back to its own SMS provider.

WhatsApp Cloud API emits four delivery states per message: sent, delivered, read, and failed. WhatsMark forwards these as webhooks to your endpoint, with the message ID and timestamp. Your system can take action on read events (mark notification as seen, stop reminder cascades, log to your CDP). Email and SMS don't give you this signal.

Meta operates a tier-based throughput cap — Tier 1 = 1,000 unique recipients / 24 hours, Tier 2 = 10,000, Tier 3 = 100,000, Tier 4 = unlimited. Utility-template volume contributes to your tier rating. Quality-rating thresholds for tier-up: maintain "high" quality for 7 days, then auto-promote. WhatsMark monitors quality in real time and surfaces alerts before Meta enforces.

For RBI-regulated communications (banking OTPs, payment confirmations), the WhatsApp Business Cloud API is recognized by RBI as an approved delivery channel for non-monetary communication. For SEBI-regulated content, the same template-approval workflow applies. WhatsMark's audit log captures every send, delivery state, and read event with timestamps — sufficient for regulator review. For Aadhaar / KYC document delivery, use the signed-URL pattern (time-bound link, expires after configured window).

The send itself is fully automated — your system fires a webhook and the message goes out, no human in the loop. But the bigger win is what happens around the message. Because these notifications land on a channel people actually open (~98%, versus ~20% for email), they get read in time to matter — a delivery-out-for-delivery alert, a failed-payment retry link, an appointment reminder. And unlike email or SMS, WhatsApp returns real delivery and read receipts, so automation can react to them: stop a reminder cascade once a message is read, trigger an SMS fallback when an OTP doesn't deliver within 30 seconds, or escalate when a payment link goes unread. The customer doesn't talk to a bot here — these are one-way utility messages — but the automation makes the whole notification loop self-correcting instead of fire-and-forget.