Broadcast Limits
Sending limits protect your deliverability and keep your messages out of spam filters. Understanding them helps you plan large sends with confidence.
Overview
When you send a bulk SMS broadcast, your messages pass through mobile carrier networks before reaching your contacts. Carriers monitor sending patterns and can throttle or block messages that appear to be spam. Volume Reach enforces per-blast and daily sending limits to help you stay within carrier thresholds and maintain high deliverability.
How It Works
Per-blast limits
Each individual broadcast you send has a maximum number of messages that can be dispatched in a single send. If your audience exceeds this limit, you will need to split your send into multiple broadcasts or stagger them over time.
Daily limits
Your account also has a daily sending cap — the total number of SMS messages you can send across all broadcasts within a 24-hour period. This cap resets each day.
Carrier throttling
Even within your account limits, mobile carriers apply their own throughput rules. During high-volume periods, carriers may slow the delivery of your messages. This does not mean messages are lost — they are queued and delivered as capacity allows. However, time-sensitive broadcasts should be sent well in advance of any deadline.
Registered A2P campaigns
Your sending limits are tied to your A2P (Application-to-Person) registration status. Registered senders generally receive higher throughput and better deliverability than unregistered senders. If you have not yet completed A2P registration, your limits will be lower. See the A2P Registration guide to get registered.
Tips & Best Practices
- Split very large audiences. If you need to reach tens of thousands of contacts, consider breaking your list into segments and sending to each segment on different days. This reduces the risk of hitting daily caps mid-broadcast.
- Schedule time-sensitive messages early. Carrier throttling means delivery is not always instantaneous for large sends. Give yourself a buffer if timing matters.
- Monitor reply volume. A large broadcast can generate a significant number of inbound replies at once. Make sure your team is ready to respond, or that you have an SMS agent configured to handle auto-replies. See AI Auto-Reply.
- Keep your list clean. Sending to stale or invalid numbers increases bounce rates, which can negatively affect your sender reputation with carriers. Regularly review and remove contacts who have never engaged.
- Avoid sending the same message repeatedly. Carriers flag identical messages sent in bulk as potential spam. Vary your message content between broadcasts.