The story is always the same. A business buys a new SIM for marketing, registers WhatsApp, imports a list, sends the first campaign that afternoon, and the number is gone by the evening or a few days later. The list was fine. The message was fine. The number was new, and it behaved like a spammer in its first hour.
Brazilian marketers have a phrase for the cure: "aquecer o chip", warming the SIM. The idea is right, but the way it is usually sold, as a fixed number of days after which you are safe, is not how WhatsApp works. This guide explains what WhatsApp scores about a new number, what "warm" means to its systems, a ramp you can follow as a rule of thumb, and the habit that keeps a number warm.
Why day-one blasts die
WhatsApp’s "Stopping Abuse" white paper says its detection runs at three stages, and the first is registration: "Since all accounts must go through registration before being able to send any messages, it is an effective starting point to concentrate our efforts." Roughly 20% of the bans it describes happened at registration.
What does it look at? Its own words: "even basic account information along with an IP address and associated carrier information can be used to teach our machine learning systems the difference between bulk and normal registrations", and "our systems can detect if a similar phone number has been recently abused or if the computer network used for registration has been associated with suspicious behavior". A new number starts life with a score already attached: the range it came from, the carrier, the IP address and the network it registered on.
Then it watches what the number does next, weighed against how suspicious the registration looked. The paper’s example of an instant ban is "an account that registered five minutes before attempting to send 100 messages in 15 seconds". Its borderline case is "a new account might message dozens of recipients who do not have the sender’s account in their contacts. This could be the beginning of a spam attack, or it could be an innocent user simply telling their contacts about a new phone number. In these cases, we consider historical information (for instance, how suspicious their registration was)".
Read those together and the day-one blast explains itself. A brand-new number, from a cheap range, on an unknown network, sending fast to people who never saved it, ticks every box, with no history to offset it.
Related: Virtual numbers for WhatsApp: what works and what gets banned · WhatsApp banned your number? Why it happens and what to do next
What "warm" actually means to WhatsApp
Warm is not a number of days. WhatsApp does not publish a waiting period, and there is no date after which a number is trusted. Warm is a history: evidence that this number behaves the way WhatsApp describes normal use. "Normal users operate relatively slowly on WhatsApp, tapping messages one at a time or occasionally forwarding content."
Concretely, a warm number has a record of real two-way conversations with people who have it saved, replies coming in as well as messages going out, a steady rhythm rather than silence followed by a spike, and no blocks or reports. Each of those is a signal the white paper names, and each takes real use to build. A number that sat in a drawer for a month is old and empty, and empty is not the same as trusted.
One refinement belongs here. People who manage large numbers of business WhatsApp numbers report that how many new people a number starts chats with is scored more heavily than its message total: "five hundred messages into existing threads sit in a different risk bucket than five hundred first-contact messages". They saw numbers that looked fine on daily totals fail on new recipients, and they add that a list of people who asked to hear from you, but have never been messaged from this number, still counts as new contact. That is a community observation, not a WhatsApp rule, but it explains a lot of bans.
Warming schedules copied from the Business API lane, with quality ratings and messaging tiers, do not translate either. A number you link as a device, through WhatsApp Web or a tool like Spun, has the same scoring every personal number has. The ramp below is a rule of thumb about behaviour, not a schedule WhatsApp has published.
Before you link the number to any tool
The advice people who manage large numbers of business WhatsApp numbers give for a fresh number is unusually specific, and it applies to any tool you link the number to, Spun included. Read it as experience, not WhatsApp policy:
- Do not scan a QR code right after registering the number. Wait a day or more before linking it to anything.
- Use the number as an ordinary user first, for several days: conversations with colleagues and acquaintances, including voice notes and files, before any tool touches it.
- When you start sending in any volume, begin at one or two messages a minute, for no more than about six hours a day, and not more than three days in a row at first.
- Introduce each new kind of activity gradually. A number that has never created a group or messaged strangers should not do a lot of either in one day.
A week-by-week ramp, as a rule of thumb
The first weeks build the history the number does not have yet. The order matters more than the counts, and replies matter more than sends throughout.
- 1
Week 1: real conversations only
Set up the profile properly: name, photo, description, hours. Then message the people who already know you, one at a time, and get them to write back: your team, suppliers, a handful of regulars. Ask each to save the number and save them in return. No campaigns, no lists, no links to anyone who did not ask.
- 2
Week 2: small batches to people who saved you
Send short, useful, personal messages to small batches of saved contacts who have already replied at least once. Keep each batch small enough to answer every reply the same day. If anyone asks you to stop, stop and remove them.
- 3
Week 3: grow the batches, keep them saved
If replies are coming in and nobody has blocked you, let batches grow and run a first proper campaign, still limited to saved contacts and people you spoke with recently, paced over a day or more. A campaign that takes ten minutes is the thing you are trying to avoid.
- 4
Week 4 onwards: settle into a cadence
Move to the rhythm you intend to keep: one useful message a week to a segment, replies answered, quiet hours respected, and a standing habit of reaching out to contacts who have gone quiet.
None of these week boundaries comes from WhatsApp. They are a pace at which a real business could plausibly be doing these things. If your number is behaving well and replies are flowing, you are warming it, whatever week it is. If it is sending to strangers in silence, no number of weeks makes that safe.
Related: How to send bulk WhatsApp messages without getting banned
The numbers practitioners publish, and how to read them
If you want counts, the most detailed public schedule comes from people who manage large numbers of business WhatsApp numbers, and they say plainly that their figures are community-tested estimates, not WhatsApp rules. Their starting point: days 1 to 3, message about 20 to 50 people a day you already know and who will reply; days 4 to 7, 50 to 100 people a day who asked to hear from you, keeping the reply rate above 30%; days 8 to 14, 100 to 200 people a day; after day 14, grow according to whether replies are keeping up. They put the highest risk in the number’s first 10 days and describe the shape as roughly doubling every three days.
Read the shape, not the counts. The shape agrees with everything WhatsApp has published: start with people who will write back, grow gradually, let replies decide the pace, and treat the first days as the fragile ones. The counts come from operations much bigger than a shop or a coaching practice. If your reply rate is falling, the day’s number is too high whatever the schedule says.
What never to do during warm-up
- Bulk-sender tools and browser extensions. The Help Center is explicit: "Don’t bulk message, auto-message, or auto-dial using WhatsApp." A new number is the account least able to absorb a burst, and the paper describes detection built to "directly target automation".
- Forwarding one message to many people. The phone’s forward-to-many feature produces exactly the burst shape the paper describes; forwarded messages are labelled and their forward count limited for that reason. A coaching business we looked at lost an established number this way.
- Adding people to groups. The paper names accounts that "quickly create dozens of groups or add thousands of users to a series of existing groups" alongside its 100-in-15-seconds example, and the Help Center asks you to get permission before adding anyone to a group.
- Links to strangers. A first message from an unknown number containing a link is the profile of the click-bait senders the paper describes, and the recipient sees report and block buttons before your name.
- Lists that are not yours. "Don’t share phone numbers without consent or use data obtained from illicit sources to message users on WhatsApp." A bought list is cold by definition, and the first-message reports it produces are the ones WhatsApp trusts most.
- Modified apps. "Do not use modified versions of WhatsApp." The paper says these clients "cannot circumvent our detection systems that run on our servers".
- Bulk number checks. People who manage many business numbers report that checking a long list of phone numbers for WhatsApp accounts, without sending anything, is activity too: one account looking up a huge set of numbers in a short window has the burst shape of a cold campaign. Split lists, space the checks, and keep them off a fresh number.
- A separate budget for first contacts. Because contact novelty is scored more heavily than volume, keep first-time recipients a small share of the day’s traffic, even when the day’s total is modest.
- Registering on a connection with a bad history. The network you register from is scored. Register and link the number from your own home or office connection, not a VPN, public Wi-Fi or a shared office.
Related: Can a shared Wi-Fi, VPN or datacenter connection get your WhatsApp banned?
What Spun does with a new number
Spun connects to the number as a linked device, the same mechanism as WhatsApp Web: nothing installed on the phone, no modified app, no contact scraping. A few defaults are designed for exactly the warm-up problem.
A newly linked number is held to a lower server send rate than an established one, and whatever pace you pick, the server sends at whichever is slower, so an optimistic setting cannot push a new line into a burst. Every send is separated by a random gap, and the Aggressive preset carries an on-screen warning that it increases ban risk.
The audience filters make weeks 2 and 3 of the ramp a single click: saved contacts only, and people you spoke with in the last 7, 30 or 90 days. Quiet hours are on by default, so a campaign started in the evening pauses at 22:00 and resumes at 08:00.
What Spun does not do is make a cold list safe. Its pacing keeps the shape of your sending inside what a person could do; it cannot change who you chose to send to. No tool can.
Keeping it warm: the ongoing habit
Warm is a state you maintain, not a milestone you pass. The number that gets banned in month six is usually one that went quiet after its launch campaign and then blasted again for the next promotion. Silence followed by a spike is the pattern, whatever the number’s age. Three habits keep an account in normal daily use, so that a campaign is a bump on top of real traffic rather than a spike out of nothing.
- Reach out to the people who have gone quiet, on a cadence per relationship: 7 days for hot leads, 30 for customers and 90 for partners are the examples Spun’s Keep In Touch view ships with.
- Answer everything that comes in. Replies are the strongest evidence that people want to talk to you. If several people share the number, run it from a shared inbox so nothing sits unread.
- Run one line per audience. A number that serves one region in one language stays small enough to stay in normal use. Spun supports multiple lines, each with its own inbox, contacts and team; a campaign sends from one line, so you choose which audience it goes to rather than pushing everything through a single number.
Related: WhatsApp marketing without getting banned: the playbook
The problems behind this, and how Spun handles each one
The warm-up mistakes above are things a shop or a coaching practice does by accident. Here is what each one does to WhatsApp’s scoring, and what Spun does about it.
- 1
It is day one and I want to send the whole list now
A number minutes old sending fast to people who never saved it is the white paper’s example of an instant ban, and there is no history to offset it. Spun holds a newly linked number to a lower server send rate than an established one and offers the Conservative preset, a random 15 to 30 seconds between messages; the ceiling slows a blast, it cannot make a cold list safe.
- 2
My list came from a spreadsheet and nobody saved my number
Messages to dozens of recipients who do not have you in their contacts are exactly the borderline case WhatsApp judges against how suspicious your registration looked. Spun’s campaign audience can be set to "Saved contacts only", and before a new conversation opens it checks that the number is on WhatsApp and refuses it if not; neither turns a stranger into a contact.
- 3
I ran one launch campaign, then the number sat quiet until the next promotion
Silence followed by a spike is the spike pattern whatever the number’s age. Keep In Touch lists the contacts you have not spoken with in 7, 30 or 90 days per label, with a quick-send box next to each, so the number stays in normal daily use between campaigns; you still write the messages.
- 4
Every campaign reaches a few hundred people I have never messaged
The share of first-time recipients is scored more heavily than the total, and a list of people who asked to hear from you but were never messaged from this number counts as new. Spun’s activity filter has a "Never contacted" setting; use it deliberately, in small batches, so first contacts stay a minority of the day’s traffic rather than the default audience. The filter selects, it does not ration the novelty for you.