Sending Single & Bulk SMS

You can send SMS messages to a single recipient, a list of numbers, or one or more Contact Groups directly from the Send page in the left sidebar (/messages/new).

Composing and Sending a Message

1. Select a Sender Identifier

   In the Sender Identifier dropdown, choose the active and confirmed Sender ID you want recipients to see on their phones.

   • If you need to register a new Sender ID, click the New Sender Identifier link right above the dropdown.
   • Only Sender Identifiers that are both Confirmed and Active (Can Be Used? = Yes) appear in this list.

2. Specify Your Recipients (To Mobile Numbers and/or Groups)

   You can provide recipients using To Mobile Numbers, Groups, or both at the same time:

   • Direct Mobile Numbers (To Mobile Numbers): Enter one or more mobile numbers separated by a space, comma (,), semicolon (;), or placed each on its own line.

     • You can include the international country prefix (e.g., +306972669766 or 306972669766) or omit it (e.g., 6972669766) to automatically use your account’s Default Sending-To Country.
     • Maximum 500 direct numbers: You can enter up to 500 mobile numbers directly into the To Mobile Numbers field in a single submission.

   • Contact Groups (Groups): Select one or more groups from the multi-select Groups field (Select Groups you want to send message to).

     • Required when sending to more than 500 recipients at once.
     • Automatic Deduplication: If a mobile number appears in multiple selected groups, Rayo SMS sends the message to that number only once within the same request.
     • Automatic Invalid Suppression: Any contact marked as Invalid (Invalid? = Yes) in your Contacts database is automatically skipped—even if it belongs to a selected group.

3. Write Your Message Body (or Reuse a Previous Message)

   Type your SMS content into the Message box (up to 1,000 characters maximum).

   • Reuse Previous Text: Click Previous Messages below the text box to open a modal showing your recently sent message bodies, then click Use This One to populate the editor instantly.
   • Watch the live Number Of Characters and Number Of Credits counters below the form as you type. (See Character Limits & Encoding for details.)

4. Set Optional Options (Reference Number, Schedule, or Simulation)

   • Reference Number: Optionally enter your own custom identifier (such as a campaign name like summer-promo-2026 or an order/customer ID). You can later filter your Sent history by this exact reference number.
   • Schedule At: Leave blank to send immediately, or pick a future date and time to schedule the delivery.
   • Simulation (Message Will not Be Sent Out): Check this box if you want to test the full submission and status workflow without dispatching real SMS messages or consuming any credits.

5. Confirm and Send

   Click the Send button and confirm the prompt (Are you sure that you want to send this message?). Your request is queued for immediate asynchronous processing (Your message has been stored for further processing).

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Direct Numbers vs. Groups Comparison

Feature	To Mobile Numbers Field	Groups Selection
Maximum Recipients per Submission	Up to 500 numbers	Unlimited
Input Format	Space, comma, semicolon, or newline separated	Multi-select from your saved Contact Groups
Can Combine Together?	Yes — you can enter direct numbers and select Groups in the same request	Yes
Duplicate Prevention (6-Hour Window)	Blocks sending the exact same message text to the same mobile number within a 6-hour window	Automatically deduplicates numbers shared across multiple groups and enforces the 6-hour duplicate protection window
Invalid Contact Suppression	Checks if the number is marked Invalid in your Contacts	Automatically skips all group members marked Invalid

6-Hour Duplicate Message Protection

To prevent accidental double-sends and protect your credits, Rayo SMS will not send the exact same SMS content to the same mobile number within a 6-hour window (has already been sent this message within the last 6 hours). This applies both when a number appears in multiple selected Groups in the same campaign and when a separate request with identical message text is submitted within 6 hours.

Testing with Zero Credit Cost

Whenever you enable Simulation (Message Will not Be Sent Out), Rayo SMS processes the request end-to-end, creates delivery records (prefixed with simulation-), and triggers webhook callbacks—without sending an actual SMS to the telecom carrier or deducting credits from your balance.