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Set up SMS in your OneSignal dashboard to start sending SMS and MMS messages. The process takes about 10 minutes, but carrier registration (10DLC or toll-free) may take weeks. Before you begin:
OneSignal SMS setup flow diagram showing provider, number, and subscriber steps

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Step 1: Select a provider

In your OneSignal dashboard, navigate to Settings > Set up SMS / RCS.
OneSignal dashboard showing OneSignal and Twilio provider options
OneSignal leverages Twilio under the hood. Choose this if:
  • You send more than 5,000 SMS per month
  • You are on a paid OneSignal plan (see pricing)
Click Book Demo with SMS Expert to get started.
While waiting for verification, you can begin designing SMS templates and completing registration requirements.

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Step 2: Set the default “From” number

Once verified, OneSignal retrieves all phone numbers linked to your account. Select a default number to use when sending. You can override this per message.

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Send a test SMS

Enter your phone number and click Send Test SMS. If the message does not arrive:
  • Confirm the default number supports SMS
  • Check Twilio logs for errors
Twilio trial accounts require recipient numbers to be pre-registered.
Click Next: Add Subscribers.

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Step 3: Add subscribers

Each phone number is a separate SMS Subscription in OneSignal. You can add subscribers through:
  • Dashboard — Upload phone numbers via CSV. See Import phone numbers.
  • SDK — Use the addSms() method to associate a phone number with a user.
  • API — Create or update users via the REST API.
  • Web prompt — Capture phone numbers with permission requests.
All phone numbers must be in E.164 format (e.g., +19999999999). Phone numbers are anonymous until you assign an External ID.

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Step 4: Configure compliance

Carrier regulations require proper consent and registration before sending SMS.
With iOS 26, SMS messages from “unknown” senders are screened out. To be recognized as a known sender, use opt-in methods where the user sends the first message — such as text-to-join keywords, tap-to-join links, or QR codes that open a pre-filled text thread.

SMS regulatory compliance

Applicable laws and requirements for SMS messaging.

SMS registration requirements

10DLC, toll-free, and short code registration.
After setup, manage your sender numbers and consent keywords in your OneSignal dashboard. Senders — Under Settings > SMS > Senders, update your default sender number and configure whether it can receive replies. Consent keywords — Under Settings > SMS > Consent Management, configure opt-in, opt-out (STOP), resubscribe (START), and help keywords with auto-responses.

SMS consent keyword management

Configure default and custom consent keywords.

SMS keywords

Set up custom auto-response keywords.

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FAQ

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Do I need a Twilio account to send SMS with OneSignal?

No. You can use OneSignal’s managed SMS infrastructure, which handles Twilio under the hood. This option is available on paid plans for accounts sending more than 5,000 messages per month. Alternatively, you can connect your own Twilio account for direct control.

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What phone number format does OneSignal require?

All phone numbers must use E.164 format: a + prefix followed by the country code and subscriber number with no spaces. For example, a US number 999 999 9999 becomes +19999999999. See E.164 format for more examples.

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How long does SMS registration take?

It depends on the registration type. Toll-free verification typically takes 1–2 weeks. 10DLC brand and campaign registration can take a few days to several weeks depending on your trust score. Short code approval takes 8–12 weeks. You can begin building templates while waiting.

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Can I use multiple sender numbers?

Yes. OneSignal retrieves all phone numbers linked to your Twilio account. You set one as the default, but you can override the sender number per message.

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After setup

Once setup is complete, you’re ready to start sending messages.

SMS overview

Send, personalize, and track SMS and MMS messages.

Templates

Create reusable SMS and MMS templates.

Journeys

Build automated multi-channel messaging flows.

Message personalization

Use dynamic content and user data in messages.

SMS message reports

View delivery and engagement metrics.

SMS FAQ

Troubleshooting, encoding, and sender types.