Campaigns
How to send mass messages on WhatsApp through the official API without losing your number
Approved template, opt-in list, sending limit and cost, in 6 steps.
To send mass messages on WhatsApp without putting the number at risk, the send must go out through the official API, with a message template approved by Meta, to contacts who authorized receiving messages from the business, in batches and during business hours. In Brazil, each delivered marketing message costs about R$ 0.32 according to Meta's official table. The point that most brings down a campaign is the contact list.
The scene is familiar. The business gathers three thousand contacts in a spreadsheet, opens WhatsApp Business on the phone and starts sending the promotion. In the middle of the afternoon, the number stops sending. The next day, it is blocked, and with it goes the history of all the customers who were talking there. Mass messaging works, but only within the rules Meta created for it.
Why does sending from the app put the number at risk?
Regular WhatsApp and the Business app were made for conversation, not for sending in volume. The same message sent to hundreds of people who did not save your number generates blocks and reports, and that is the signal that leads Meta to restrict or ban the account.
On the official API, mass sending is built in. The message goes through approval, the category defines the price, and Meta controls how many people you can reach per day according to the account's history. If you are still on the app, it is worth understanding first the difference between WhatsApp Business and the official API.
Step 1: which template category should you choose?
Every message sent to someone who has not spoken to you in the last 24 hours needs to be an approved template. Meta classifies each template into one of three categories, and the category defines the price.
| Category | What it is for | Example | Cost in Brazil |
|---|---|---|---|
| Marketing | Sell, promote, reactivate | "The October class opens on Monday" | About R$ 0.32 |
| Utility | Something linked to a customer action, with no promotion | "Your appointment is confirmed for Thursday at 3 p.m." | R$ 0.035 |
| Authentication | Verification code | "Your code is 482913" | R$ 0.035 |
The rule that catches businesses off guard the most: mixed content becomes marketing. An appointment reminder with a coupon at the end is reclassified as marketing, and starts to cost almost ten times more. Meta makes it clear in its documentation that the business is responsible for checking the category assigned to its templates.
Step 2: how do you build the sending list?
It is the list that decides whether the campaign delivers or brings the number down, and four precautions solve almost everything.
Send only to those who authorized it. Meta requires the contact to have accepted receiving messages from the business on WhatsApp. Record where each authorization came from: a form, the checkout, the conversation itself.
Segment by last interaction. Those who spoke to you in the last 90 days reply more and report less than a base that has been idle for a year. For this old base, a Click to WhatsApp ad is usually a safer way in than a direct message.
Remove immediately those who asked to leave. Anyone who replied "stop" or "I don't want to receive this anymore" leaves the list the same day.
And start small. Send first to a few hundred contacts, measure replies and blocks, and only then expand.
If the list came from a purchased spreadsheet or from contacts who never spoke to the business, the answer is simple: do not send.
Step 3: how do you write a template that gets approved and answered?
One intention per message. An invitation, a reminder or an offer, never all three in the same text. The business name right at the beginning, so the contact knows who is talking before deciding whether to read. The name variable ("Hi, {{1}}") instead of "Hello, customer". And a question or reply button at the end.
The button does more than make replying easier. When the contact taps it, it opens the 24-hour service window, and from there you talk with free-form messages.
An example of a marketing template for a language school:
Hi, {{1}}! This is [school name]. The October class of the English course for adults opens on Monday. Would you like to receive the schedule?
Avoid excessive capital letters and absolute promises ("guaranteed", "last chance"). This pattern may be rejected in the approval.
Step 4: how many messages can I send per day?
Meta limits how many different people the business can reach with business-initiated messages in 24 hours. It is a limit on unique contacts, not on messages. Since October 2025, this limit is shared by all numbers in the same business portfolio at Meta, so adding a new number does not increase capacity.
The limit starts low for new accounts and rises automatically as sending quality holds up. Quality is measured by the contacts' reaction, and it appears in WhatsApp Manager in three colors: green, yellow and red. Yellow freezes the growth of the limit. Red can reduce it.
In practice, split the send into batches throughout the day, prefer business hours (a sales message at 11 p.m. increases the chance of blocking) and check the number's quality after each campaign. If it drops, stop, review the list and the text, and only then return.
Step 5: how much does a mass messaging campaign cost?
Meta charges per delivered template, according to the category and the country of the destination number. According to the official table in reais, one thousand marketing messages delivered in Brazil cost about R$ 322. Utility and authentication templates have a progressive volume discount; marketing does not.
The customer's reply is not charged. The business's replies within the 24-hour window start being charged from October 1, 2026, after a free allowance of 1,000 messages per number each month. The complete math is in New WhatsApp billing in October 2026.
Step 6: how do you know whether the campaign sold?
Delivery and read rates tell you whether the message arrived, not whether it sold. To measure results, the campaign needs to be linked to the funnel: who replied became a deal, at what stage that deal is, and how much it closed in value.
If your campaign report ends at "read", the link to the CRM is missing.
Checklist before sending
Before hitting the button, check seven points: the send goes out through the official API; the template is approved, in the right category and with no mixed content; the list has only those who authorized it and is segmented by last interaction; there is a reply button or a question at the end; the send goes in batches and during business hours; someone will look at the number's quality afterwards; and the replies go straight into the funnel, with a defined owner.
Frequently asked questions
Can I send mass messages through WhatsApp Business?
The app was not made for sending in volume, and this exposes the number to blocking. The sending provided for by Meta is through the official API, with an approved template.
Do I need an approved template for every campaign?
Yes, for messages sent to those who have not spoken to you in the last 24 hours.
How much does a campaign message on WhatsApp cost?
In Brazil, about R$ 0.32 per delivered marketing message and R$ 0.035 per utility message, according to Meta's official table in reais.
Why was my utility template charged as marketing?
Because it had promotional content along with it, such as a coupon or an offer. Mixed content is classified as marketing.
Does adding another number increase the sending limit?
No. Since October 2025, the limit is shared by all numbers in the same business portfolio.
What happens if many people block my number?
Quality drops and the daily limit can be reduced. Stop the campaign and review the list and the text before returning.
