Will my carrier block my number if I send bulk SMS?

Why carriers limit some numbers

Carriers protect their networks and their customers from spam. In most cases they look at one or more of three things:

• Monthly volume: how many SMS your plan includes, or what its fair use policy allows.
• Speed: how many SMS leave the number in a short time.
• Different recipients: how many different numbers you text in a day, a week or a month.

A number is also more likely to be limited when it gets many complaints or STOP replies, or sends messages that look like scams.

Check your plan before your first campaign

Before you send a campaign, check three things in your mobile plan:

• How many SMS a month it includes, or whether it is unlimited.
• Whether there is a daily or monthly limit on SMS.
• Whether there is a limit on how many different numbers you can text.

For regular use, we recommend an unlimited business plan. Many carriers offer one. Then set DroidSender's speed, sending hours and daily limit to stay inside your plan.

What we see among DroidSender users: numbers do not get blocked when the sender knows how many SMS their plan includes each month and whether it limits how many different numbers they can text, and stays within those limits.

How to find your plan's limits

• Your carrier's app or online account shows how many SMS your plan includes and how many you have left.
• Most carriers also have a short code you dial or text to check your balance.
• Daily, monthly or different-number limits are in your plan's terms, usually under "fair use".
• If you can't find them, call or message your carrier and ask: "How many SMS can I send per day and per month, and is there a limit on how many different numbers I can text?"

What DroidSender does for you

• Lets you choose how fast each campaign sends. The default, Automatic, sends at the pace the phone and the network can handle and slows down if the network pushes back.
• Sends only in the hours and on the days you choose, and up to the daily limit you set.
• Pauses sending automatically if the network refuses several messages in a row, or if your carrier texts the phone to say SMS is restricted, and emails you so you can check.
• Records STOP replies and blocks those numbers for your account, in campaigns, the API and the inbox.
• Checks every campaign for scams before the first SMS goes out. Suspicious campaigns are held and reviewed by a person.
• Lets you connect more than one phone (up to 3 on Pro and 10 on Business), so you can split a large list into several campaigns, one per phone.

Choose your sending speed

You can change the speed at any time, including during a campaign. The change applies to the messages that have not gone out yet.

Choose when and how much it sends

• Sending hours: messages only go out within the hours you choose, for example 9:00 to 19:00.
• Days of the week: pick the days it can send, for example Monday to Friday.
• Daily limit: set a maximum number of messages per day for the campaign.

Hours, days and the daily limit are set for each campaign and follow your account's time zone. When the day's limit is reached or the sending window closes, DroidSender stops and carries on automatically in the next allowed window, until the whole list has been sent.

Keep messages short

Long messages count as several SMS on your mobile plan, and very long messages sent in large volumes can start to fail. Keep each message between 1 and 5 SMS. See how SMS length works.

What you should do

• Only text people who gave you their number and expect to hear from you.
• Say who you are in the message.
• If it makes sense for your case, personalise messages with the columns in your file instead of sending identical texts.
• Keep each message between 1 and 5 SMS.
• Start with Careful on a new number or for your first large campaign, then move to Automatic.
• Spread large lists with a daily limit and sending hours, or across several phones. DroidSender continues on its own the next day.
• Use links to your own website, not link shorteners, which carriers often treat as a spam signal.

Country notes

• Europe and the UK: mobile plans usually include a fair use policy for texts. Check yours, and follow the GDPR and ePrivacy rules (PECR in the UK).
• United States: carriers expect large-scale business messaging to go through registered business numbers, and can filter high-volume marketing sent from a personal line. If you send marketing at scale in the US, check your carrier's terms first and follow the TCPA.

If your carrier limits your number

In practice, nothing serious happens. Messages start failing, DroidSender pauses the sending and emails you. In most cases the limit is temporary, and a call to your carrier is enough to lift it. DroidSender then resumes slowly on its own, after a test message goes through. You can also switch to a slower speed, lower the daily limit or connect another phone. Your contacts, campaigns and inbox stay as they are.