WhatsApp is the primary messaging channel for a large share of the world, and for ecommerce it does something email and SMS cannot: the customer can reply, and you can answer. That single property makes it the best channel for removing purchase objections.
It is also the channel with the most rules. Templates need approval, messages are priced by category, and there is a 24-hour clock that governs when you can say what you like. This guide explains how the platform actually works, what it costs, how to set it up, and how to design around the constraints rather than fight them.
The two things that govern everything
1. The 24-hour customer service window
When a customer sends you a message, a 24-hour window opens. Inside it you can reply freely — any content, any format, no template, no charge from Meta. When it closes, you can no longer send free-form messages to that person.
Every good WhatsApp programme is organised around this. A message that prompts a reply does not just measure engagement; it opens a window in which your team can have a real conversation at no message cost. That is why "reply YES for sizing help" outperforms a message with only a link.
2. Template messages
To reach someone outside an open window, you need a template Meta has reviewed and approved. Templates have fixed structure with variable slots — you cannot improvise.
Every template carries a category, and the category sets the price:
- Marketing — promotions, offers, announcements, re-engagement. The most expensive category, deliberately.
- Utility — messages tied to a specific transaction the customer initiated: order confirmations, shipping updates, delivery notifications, appointment reminders. Cheaper than marketing.
- Authentication — one-time passcodes and login codes. Priced separately again.
- Service — your free-form replies inside a customer-initiated window. Free.
Meta bills per delivered template message, with rates varying by category and by the recipient's country. The practical consequence for planning: your WhatsApp cost is a function of how many marketing templates you send. A programme weighted toward utility messages and conversations costs a fraction of one built on promotional blasts, and usually performs better.
Getting set up
What you need
- A Meta Business account, with business verification completed.
- A phone number that is not currently active on the WhatsApp consumer app or the Business app. Migrating a number off the Business app is possible but it is a one-way move — plan it deliberately.
- A display name that meets Meta's naming policy.
- A platform to connect through.
How CampGain connects
CampGain connects to your own WhatsApp Business Account rather than sending on behalf of a shared one. Three routes:
- Embedded Signup — a Meta-hosted popup that creates or selects your WhatsApp Business Account, picks the phone number, subscribes the account to webhooks, and registers the number for the Cloud API. This is the standard production path, and it takes minutes rather than days.
- Meta test number — connect Meta's free test number manually to try the flow end to end before committing a real number.
- Twilio — if you already run WhatsApp through your own Twilio account, connect that instead.
Because the WhatsApp Business Account is yours, your quality rating, your templates, and your number stay with you.
Opt-in is required
Meta requires that you have opt-in before messaging someone, and it must be clear that the opt-in is for WhatsApp specifically from your business. An email subscriber is not a WhatsApp subscriber. The opt-in can be collected almost anywhere — checkout, a website form, a chat entry point — but it has to be explicit and recorded.
Getting templates approved
Template rejection is the most common early frustration, and it is nearly always one of a short list of causes.
- Category mismatch. Submitting promotional content as utility because it is cheaper is the single most frequent rejection. Meta reads the content, and repeated mismatches affect your account standing.
- Variables with no sample values. Every placeholder needs an example so a reviewer can see what the message looks like filled in.
- Variables at the very start or end. A template that begins or ends with a placeholder can render as an incomplete message and is rejected.
- Adjacent variables with nothing between them, for the same reason.
- Policy breaches — prohibited categories, misleading claims, or unrelated link destinations.
- Formatting problems — placeholder text left in, broken structure, unsupported characters.
Two habits that save time. Write templates so they read correctly when every variable is empty or unusually long — that is how they get reviewed and how they eventually render for a real contact. And submit early: approval is not instant, and discovering a rejection the morning of a launch is avoidable.
Quality rating and messaging limits
Meta tracks how recipients respond to your messages and assigns your number a quality rating. Blocks and "report business" actions drive it down; low ratings reduce your messaging limits and can restrict your template categories.
Alongside that sits a messaging limit — the number of unique customers you can message in a rolling day. It increases as you send at good quality, and it drops if quality falls. Which means WhatsApp is not a channel you can scale in one step; you build capacity by sending well.
What protects the rating:
- Send fewer marketing templates than you think you should. Frequency is the main driver of blocks.
- Make utility messages genuinely useful. Shipping updates are welcome; a "utility" message that is really a promotion is not.
- Answer replies. A business that messages and never responds gets reported.
- Honour opt-outs immediately, however they are worded. WhatsApp has no universal STOP keyword, so you have to handle this yourself.
What WhatsApp is actually good at
Ranked by how well they usually perform:
- Order and shipping updates. High open rates, genuinely wanted, cheap utility category, and they deflect support tickets. Start here.
- Cart recovery with a conversation opening. Name the product and invite a question. The reply opens a free window in which your team can close the objection.
- Support and pre-sales questions. The channel's native strength — sizing, availability, delivery, returns.
- Back-in-stock alerts. The recipient explicitly asked for this message, which makes it the rare promotional send nobody resents.
- Post-delivery follow-up. A short check-in that produces reviews and catches problems before they become refunds.
What performs badly: broadcast promotions to your whole list. Expensive per message, hardest on your quality rating, and it teaches people to block you.
Measuring WhatsApp honestly
One measurement trap catches nearly everyone. A WhatsApp read receipt only arrives if the recipient has read receipts enabled — and many people switch them off. Your WhatsApp "open rate" is therefore structurally lower than your email open rate, and the difference says nothing about how the channel performed.
Compare across channels on clicks, replies, and attributed revenue. Use delivery rate to catch real problems: a drop usually means template or policy trouble, not disinterest.
Also worth watching: accepted is not delivered. Meta can accept a message and still not deliver it — a per-recipient marketing cap, for example, will silently drop it. The reason is available in the delivery status, and it is the difference between fixing something and guessing at it. Our campaign analytics guide covers this pattern across channels.
What CampGain provides
- Your own WhatsApp Business Account, connected through Meta's Embedded Signup or your Twilio account.
- A template builder plus curated presets written against Meta's category rules — correct category, sample values on every variable, and no placeholders stranded at the start or end.
- WhatsApp as a step in multi-channel campaigns, with per-recipient template variables drawn from your contact data and synced Shopify catalog.
- A shared team inbox. Threads can be assigned to an individual or a whole team, with canned replies and a composer that knows whether the 24-hour window is open — so nobody writes a free-form reply that cannot be sent.
- Automated first responses on a visual canvas, with handoff to a human when the conversation needs one.
- Owner, admin, and agent roles so a support team can work the inbox without access to campaigns and billing.
- Delivery and read status per message, with the provider's stated reason on failures.
See how the WhatsApp features fit together.
A sensible first 30 days
- Week 1 — connect your account, submit utility templates for order confirmation and shipping updates, and add a WhatsApp opt-in at checkout.
- Week 2 — turn on transactional messages. They are cheap, welcome, and they build the quality rating you will need later.
- Week 3 — set up the inbox. Decide who answers replies and how fast. This is the step people skip, and it is the one that determines whether WhatsApp works for you.
- Week 4 — add one marketing use case, ideally cart recovery with a reply invitation. Measure replies and attributed revenue, not opens.
Ordering it this way means your first marketing message goes out from a number with a track record, to people who have already had a good experience with you on the channel. That is worth more than any template you could write.
For how WhatsApp sequences alongside email and SMS, see our multi-channel drip campaign guide; for the rules on the SMS side, the SMS compliance guide.