Sling FAQ: common questions about messaging and API

How does your system work?

Sling uses three delivery methods to send messages to recipients:

SenderID — a registered name or number that appears as the sender on the recipient’s device
Long Code — a standard-length phone number used for two-way messaging
Short Code — a short, memorable number typically used for high-volume or marketing messages

The method used depends on your SenderID configuration and the message type you select.

Can I send SMS using my phone number?

Yes, you can send SMS from your own phone number. To do this, you will need to register your SIM card with Sling. Contact the team at [email protected] for more information on how to get set up.

Can I get SMS at a cheaper rate?

Sling already sends SMS at competitive low rates. If you are a reseller or a corporate entity sending high volumes, you may qualify for an additional discount. Reach out to [email protected] to discuss pricing options.

What phone number formats are accepted?

When specifying a recipient number in the to parameter, you can use any of the following formats:

11-digit local format — 08xxxxxxxxx
Country code without plus — 234xxxxxxxxxx
Country code with plus — +234xxxxxxxxxx

All three formats are accepted across the SMS, RCS, and Truecaller APIs.

What is a SenderID?

A SenderID is the name or number that appears in the “From” field on a recipient’s device when they receive your message. Instead of seeing a random number, recipients see a recognisable brand name or registered number.You must register your SenderID before using it in API requests. Visit app.sling.com.ng/panel/sender-ids to register and manage your SenderIDs.

Use a SenderID that clearly identifies your brand so recipients recognise your messages immediately.

What is the difference between transactional and promotional messages?

The type parameter controls how your message is routed:

transactional — for critical, time-sensitive messages such as OTPs, delivery alerts, and account notifications. These are given priority routing.
promotional — for marketing and advertising content. These follow standard routing and may be subject to additional carrier restrictions.

Set the type field in your request body to transactional or promotional depending on the nature of your message. If omitted, the platform uses the default route associated with your SenderID.

How do I check if a message was delivered?

Use the message status endpoint to look up delivery status for any message you have sent:

GET /api/v1/status/{message_id}

Replace {message_id} with the message_id value returned in the response when you originally sent the message. A successful response includes a status_delivery field indicating whether the message was delivered.

Store the message_id from each send response so you can query its status at any time.

What happens if I don't have enough credits?

If your account does not have sufficient credits to send a message, the API returns a 400 Bad Request error with the following response body:

{
  "status": "fail",
  "credit_used": "0",
  "details": "insufficient credit"
}

No message is sent and no credits are deducted. To resolve this, top up your credit balance from the dashboard before retrying the request.

What is fallback_sms in RCS?

When sending an RCS message, you can include "fallback_sms": true in your request body. If the recipient’s device does not support RCS — or if the message cannot be delivered over RCS — Sling will automatically resend it as a standard SMS instead. Use "fallback_sms_sender" to set the SMS Sender ID for that fallback (for example, "Sling" while "sender" is "RCS").Setting "fallback_sms": false means the message is only attempted over RCS, and no SMS fallback is used.

{
  "sender": "RCS",
  "to": "08140363541",
  "message": "Hello from Sling",
  "type": "transactional",
  "template_type": "text",
  "fallback_sms": true,
  "fallback_sms_sender": "Sling"
}

Where do I find my API token?

Your API token is available in your Sling dashboard. To retrieve it:

Log in to your account at app.sling.com.ng
Navigate to app.sling.com.ng/panel/account/api
Copy your API token and include it in the Authorization header of every request:

Authorization: Bearer {API TOKEN}

Keep your API token private and do not share it publicly.

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