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CloudVNO

SMS Overview

Introduction to CloudVNO's Programmable SMS API — capabilities, concepts, and getting started.

What is Programmable SMS?

CloudVNO's Programmable SMS API lets you send and receive SMS messages programmatically in 150+ countries. Use it for transactional alerts, two-way conversations, marketing campaigns, appointment reminders, and more.

Core Concepts

Phone Numbers

To send SMS, you need a CloudVNO phone number. Numbers can be:

  • Long codes — Standard 10-digit numbers (US: +1XXXXXXXXXX). Best for conversational P2P messaging.
  • Short codes — 5-6 digit numbers (US only). Best for A2P campaigns at high volume.
  • Toll-free numbers — Best for mid-volume A2P with higher throughput than long codes.

Provision a number →

Message SID

Every message has a unique SID (e.g., SM1a2b3c4d5e6f...). Use it to look up message status, handle callbacks, and debug.

Message Status Lifecycle

queued → sent → delivered
                    └→ undelivered (carrier rejection)
         └→ failed (before leaving CloudVNO)

Status updates are delivered via webhooks.

Encoding

  • GSM-7: Standard SMS encoding, supports 160 characters per segment
  • Unicode (UCS-2): Required for emoji and non-Latin characters, limits to 70 characters per segment
  • Concatenated SMS: Long messages are split and reassembled automatically

A2P vs P2P Messaging

A2P (Application-to-Person)P2P (Person-to-Person)
Use caseMarketing, notifications, alertsConversational, 2-way support
Number typeShort code, toll-free, 10DLC long codeLong code
ThroughputHigh (100-500 MPS)Low (1 MPS per number)
Registration10DLC required for US long codesNone

Compliance

Before sending in the US, ensure you:

  1. Register your brand and campaign for A2P 10DLC (required since 2021)
  2. Include opt-out instructions in marketing messages ("Reply STOP to unsubscribe")
  3. Honor opt-outs immediately — CloudVNO auto-manages opt-outs for you
  4. Follow TCPA guidelines for time-of-day restrictions

Learn about compliance →