SMS notification API: send alerts and notifications to customers from your own number

Published September 22, 2026 and updated September 22, 2026

Some notifications have to reach the person now: a job finished, a payment failed, a delivery is at the door, a server is down. Email is not that channel, because it waits in an inbox behind everything else and half of it never gets opened. A text from a number the customer already knows arrives in seconds, and because it is a real number they can answer it instead of opening a ticket. With textbee the sender is an Android phone holding your SIM, so the message comes from your own number, recipients can reply, and the Pro plan, up to 5,000 messages for $9.99 a month with no per message fee.

How it works

Trigger the notification from the event in your system rather than from a schedule, so the text goes out the moment the state changes.
Call POST /gateway/send-sms with one recipient in E.164 and a message under 160 GSM-7 characters that names your business and says what happened.
Record the returned smsBatchId on the event row, so support can tell whether the notification went out.
Listen for the MESSAGE_DELIVERED and MESSAGE_FAILED webhooks to update that row, and for MESSAGE_RECEIVED to catch replies; on a failure, retry once or fall back to email.

Send it

The API key comes from the dashboard and the phone registered on your account does the sending. Recipients are E.164 numbers; the example is fictional.

send-notification.sh

curl -X POST https://api.textbee.dev/api/v1/gateway/send-sms \
  -H "x-api-key: $TEXTBEE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"recipients": ["+12015550123"], "message": "Main Street Clinic: your lab results are ready. Reply CALL and we will phone you."}'

Message template

Placeholders in double braces are filled per recipient by your code or by the CSV upload in the dashboard. Keep the result under 160 GSM-7 characters so it stays one segment.

template.txt

{{ business }}: {{ event }}. {{ next_step }}. Reply STOP to opt out.

Consent and compliance

A notification about a relationship the customer already has is transactional, and the number they gave you when they signed up or checked out is the prior express consent 47 CFR 64.1200 asks for. Anything that sells something is marketing and needs separate written consent. Honour STOP on both, and keep the promotion out of the status update.

In the United States, 47 CFR 64.1200 requires prior express consent for automated texts and prior express written consent for marketing, and a recipient may revoke consent in any reasonable manner. ecfr.gov, checked on September 4, 2026
The CTIA Messaging Principles and Best Practices expect a business sender to hold consent, hold express written consent for marketing, and honour opt-out requests. api.ctia.org, checked on September 4, 2026

Honest limits

One phone sends roughly 10 to 15 messages a minute, so a large blast takes time to drain. That suits event driven traffic, where messages arrive a few at a time, and it does not suit a burst of thousands at once, such as an outage alert to every customer, which needs more devices or a carrier route.

One phone sends roughly 10 to 15 messages a minute, so a large blast takes time to drain. Carriers can filter bulk patterns on consumer SIMs. Marketing messages still need consent from the recipient under the local rules.

Frequently asked questions

What is an SMS notification API?

It is an HTTP endpoint your application calls to send a text when something happens in your system. You POST the recipient and the message, the API hands it to a sender, and a webhook tells you whether it was delivered. With textbee the sender is the SIM in an Android phone you own, so the customer sees your own number.

How much does it cost to send SMS notifications?

A textbee plan is flat: Free covers 300 messages a month, Pro is $9.99 a month for up to 5,000, and Scale is $29.99 a month for up to 25,000. There is no per message fee on top. Your SIM plan still bills its own rate for the texts it sends, which is often unlimited on a consumer plan.

Can customers reply to a notification?

Yes. The message goes out from your own number, so a reply comes straight back to it and lands in your account. Read replies from a webhook or from GET /gateway/messages and route them to whoever handles that event.

Do I need 10DLC registration for notifications in the US?

No. 10DLC registers brands and campaigns on numbers a messaging platform provisions, and textbee sends from the SIM in your own phone, so there is nothing to register. The consent rules, STOP handling and your carrier fair use terms still apply, and marketing at volume belongs on a registered route.

Sources

Consent rules, ecfr.gov, checked on September 4, 2026
Consent rules, api.ctia.org, checked on September 4, 2026