You send to 400 contacts. The first 60 arrive. The rest do not, and nothing tells you so. This is the most common way a large send fails, and it is not a bug in the app — it is your carrier deciding you look like a spammer.
What carriers are watching
Consumer mobile plans are built for people who send a few dozen messages a day. Send several hundred in a few minutes and you trip anti-spam systems that watch for:
- Rate — messages per minute or per hour from one number.
- Volume — total messages per day, against a baseline of what your line normally does.
- Sameness — many recipients receiving identical text is the classic bulk signature. This is one of the underrated benefits of personalising with names: the messages genuinely differ.
- Failure rate — a high proportion of dead numbers is the signature of a purchased list, which is why cleaning the list matters beyond the wasted cost.
- Complaints — recipients reporting your number as spam is the fastest route to being blocked.
The numbers, with a caveat
Carriers publish very little and change thresholds without notice, so treat any specific figure as folklore rather than fact. The shape of it, from what senders report:
- Somewhere around 20–50 messages in a short burst is where throttling commonly begins on a consumer plan.
- Daily ceilings of a few hundred to around a thousand are frequently mentioned.
- Some carriers throttle silently, some queue and deliver slowly, some drop messages entirely.
- Business and enterprise plans are more permissive. Prepaid plans are usually stricter.
The honest summary: nobody outside the carriers knows the real numbers, they vary by country and plan, and they change. Which is why the practical answer is not “find the limit” but “stay well below wherever it is”.
Batching, and why it works
Splitting a send into blocks with pauses keeps you under the rate thresholds and gives the network time to clear the queue. Both our apps do this: the Android app’s sending wizard walks you through configurable batches, and the iPhone app splits large sends into blocks automatically.
Reasonable defaults, adjusting for your own results:
- 20–50 recipients per batch.
- A few minutes between batches rather than back-to-back.
- A few hundred per day as an upper bound on a consumer plan.
For anything larger, spread the send across days rather than trying to force it through in one session. That is what the iPhone app’s Campaigns feature is for: give it 3,000 contacts and ten days, and it computes a daily quota, notifies you each day, tracks who has already received the message and shows progress. It converts an impossible send into a short daily routine — and it happens to be exactly the pattern that does not look like a spam burst.
Signs you are being throttled
- Messages sit in “Sending” for a long time, or arrive hours late.
- The first batch delivers and later ones do not.
- Delivery failures appear only above a certain volume.
- Everything works again the next day.
If that pattern fits, reduce the batch size, lengthen the pauses, and spread the send over more days.
If your number gets blocked
It happens, usually after repeated large sends or complaints. Symptoms: messages stop delivering to everyone, not just a list.
Contact your carrier. Explain what you are doing — texting your own customers, from your own phone, with consent. Carriers are generally reasonable when the activity is legitimate, and they can lift a flag. What will not help is repeating the pattern that caused it.
If your volume genuinely requires thousands of messages a day, a consumer mobile plan is the wrong tool and no app changes that. At that scale you want a business messaging plan or a proper gateway — see bulk SMS services versus your own phone.
Step by step
- Keep batches to 20–50 recipients, not one large blast.
- Pause a few minutes between batches so the queue clears.
- Stay in the low hundreds per day on a consumer plan.
- Personalise the message so recipients are not all receiving identical text.
- Clean the list first — a high failure rate is itself a spam signal.
- Spread very large lists over days using a multi-day campaign rather than forcing a single send.
Questions people ask
How many texts can I send per day before being blocked?
There is no published number and it varies by carrier, country and plan. Reports cluster around a few hundred per day on consumer plans. Staying in the low hundreds, in batches, is the safe approach.
Why did only some of my messages arrive?
Almost certainly throttling: the carrier accepted the first batch and dropped or delayed the rest. Smaller batches with pauses fix it.
Will I be told if a message was blocked?
Usually not. SMS gives poor feedback, and silent dropping is common — which is why prevention matters more than diagnosis.
Does an unlimited plan mean unlimited mass texting?
No. “Unlimited” refers to billing, not to anti-spam thresholds. Both exist independently.
Is sending a few hundred texts a day going to get me in trouble?
Not if the recipients consented, the content is legitimate and you spread it out. Trouble comes from purchased lists, high failure rates and complaints — not from volume alone.