uni-msgWhatsApp bulk messaging: a practical guide that keeps your number alive
Most guides to WhatsApp bulk messaging skip the only part that matters: the way you send determines whether your number survives the month. Here is how it works, what gets numbers banned, and a schedule you can copy.
What WhatsApp bulk messaging means
Bulk messaging is sending the same core message to many recipients — order updates, appointment reminders, a promotion, a re-engagement campaign. There are three ways to do it, and they are not equivalent.
- Broadcast lists in the WhatsApp app. Free, but capped at 256 recipients per list, and messages only arrive for people who saved your number. Fine for a handful of contacts, useless at scale.
- The official WhatsApp Business API. Meta-approved, needs pre-approved templates, and charges per conversation. Built for volume and durability. See our comparison of the API options.
- An unofficial multi-device integration like uni-msg, which links your number as a companion device. No approval, no templates, no per-message fee — but it is against WhatsApp’s Terms of Service and carries ban risk. Read the ban guide before you commit to it.
Why numbers get banned (it is not the volume alone)
People assume there is a magic daily number that is safe. There is not. WhatsApp’s enforcement is driven mostly by how recipients react to you, not by a counter.
- Blocks and reports. The single strongest signal. A high block rate on a young number will end it quickly.
- A cold number sending hot. A number registered yesterday that sends 500 messages today looks exactly like a spammer, because that is what spammers do.
- Identical text at scale. Byte-identical messages to hundreds of recipients are trivial to cluster and flag.
- No inbound. Real businesses have conversations. Pure outbound with zero replies is an anomaly.
- Messaging strangers. Purchased or scraped lists produce blocks at a rate no amount of throttling will save you from.
Consent is the actual safety feature. Every technical control below only buys you time if the people receiving your messages want them.
A warm-up schedule you can copy
New numbers need to look like they are being adopted by a human, not commissioned as a broadcast tower. A conservative ramp:
- Days 1–2: 10–20 messages a day, mostly replies to real people.
- Days 3–5: 30–50 a day. Keep a genuine two-way ratio.
- Days 6–10: 80–150 a day, spread across working hours.
- Days 11–14: 200–400 a day if block rate stayed near zero.
- After two weeks: scale gradually, and never double overnight.
If blocks or reports rise at any step, drop back a level and stay there. uni-msg applies a warm-up ramp and a per-number daily cap automatically, but you should still watch the response signals yourself.
Sending settings that matter
- Randomised delays. Five to fifteen seconds between messages beats a fixed interval, which is itself a pattern.
- Message spinning. Vary greetings, emoji and sentence order so no two recipients get an identical payload.
- Personalisation. Merge fields like
{{name}}both improve replies and break up the text. - Working hours. Send in the recipient’s daytime. A 3am message earns blocks.
- An opt-out line. “Reply STOP to unsubscribe” converts a would-be report into a quiet removal. This one line protects your number more than any throttle.
Measure the things that predict a ban
Delivery rate and read rate tell you about reach. Block rate, report rate and reply rate tell you whether you are about to lose the number. Watch the second group. If messages stop showing a second tick across many recipients, stop the campaign and investigate before sending more.
Doing it in uni-msg
Connect a number, import contacts, write a template with variables, then set delay range, working hours, warm-up and spinning before starting the campaign. Replies land in the unified inbox alongside every other number, so a bulk send turns into an actual conversation rather than a dead end.
Start free → · Next: how to avoid a ban, and recover from one