Is this really unlimited SMS?
How can we really send "Unlimited SMS?"
This does not mean however that you can just blast as many messages as you want as they are generally governed by their "Fair Use Policy".
Sending excessive blasts or messages to quickly may result in getting your Number or Apple ID blocked by the carrier.
To help protect your number from getting blocked, ensure stable performance, reliable message delivery, and fair usage, myCRMSIM uses a smart adaptive rate-limiting system to manage message flows.
- 15-Minute Window:
The system monitors messages sent over a rolling 15-minute period. - Free Limit:
Users can send up to 30 messages every 15 minutes with no restriction. - Dynamic Delays:
After 30 messages, delays gradually increase for each additional message. - Maximum Delay:
Capped at 15 minutes (900 seconds). - Soft Rejection:
If delays exceed 15 minutes, new messages are not queued and marked as FAILED_OVERFLOW.
- The system may pause message sending temporarily.
- You may see a "Too Many Requests" (429) message.
- This is a soft rejection, meaning the system is protecting you and others from message overload.
✅ Protect user numbers from getting blocked
✅ Ensures fair usage for all users
✅ Prevents overloads during peak usage
✅ Keeps the system responsive and reliable
✅ Complies with platform constraints (like AWS limits)
✅ Gives clear feedback when limits are hit
Product Comparison Table
| Product | SMS | iMessage | |
| Recommended Max Sending volume | 1 Per Minute | 50 Unique Numbers Per Day | 1 Per Minute |
| Type | Android Only | iMessage | Android or iPhone |
| Requirements | Android phone + SIM | iPhone + SIM + Mac | Android or iPhone |
| Multi Sim | Yes | Yes | Yes |
| Free AI Chatbots Included | Yes | Yes | Yes |
| Calls | Coming Soon | Coming Soon | Coming Soon |
| eSim Compatible | Yes | Yes | Yes |
| A2P Required | No | No | No |
| Fixed Cost SMS | Yes | Yes | Yes |
| Message Format | SMS Only | iMessage + SMS | |
| Best For | Database Reactivations & Conversational | Conversational and Low DBR | Database Reactivations & Conversational |
If you wish to send out mass SMS to hundreds or even thousands of people at once best practice is to use drip mode to send SMS campaigns with MAXIMUM one SMS every 60 seconds using our drip campaign template.
(NOTE: Do not use the native SMS Broadcast Drip feature in High Level. You cannot control the time delivery by contact. Also the drip feature may keep dripping messages even outside of the times it is set, even though the messages will not send. They may queue until the next scheduled time and then drop them all at once which may get your sim card blocked)
Android phones have an inbuilt limitation that may be triggered if you exceed more than 30 SMS in 30 minutes so our recommendation is not to exceed this.
If you exceed these limits you may get a warning on the phone similar to this but you can also override it by following these steps here.
Messages may be Queued until you click Allow
Exceeding these levels may get your account flagged with your provider.
Any limitations imposed by country regulations will still apply, for example France have a limit on the number of SMS that can be sent per month through a SIM card.
We recommend that if starting out with a new SIM card that you begin at a slower rate and bring the rate up.
Do not start a new SIM card with 1 SMS per minute in drip mode as this is likely to be flagged as suspicious activity.
If you are starting out then begin any mass DBR at 1 message every 5-10 minutes and reduce over time from there. This depends from country to country, sim plan to sim plan. Very similar to email warmup delivery rates can be affected by age and use.
Once up and running and any initial messages have been sent a conversational AI chat can easily have a normal message conversation sending back and forth several sms in a minute since that would emulate normal human behaviour.
If you wish to send more SMS then you would need to get additional SIM cards and add them to your sub-account using our Multi SIM option.