What is A2P SMS? Application-to-Person Messaging

A2P SMS (Application-to-Person SMS) is any text message sent from a software application to a mobile phone user. When you receive an OTP code from your bank, a shipping notification from Amazon, or a flash sale alert from a retailer—that’s A2P messaging.

A2P SMS represents a $70+ billion global market and is the backbone of business-to-consumer mobile communication.

A2P vs P2P: The Core Difference

Aspect	A2P (Application-to-Person)	P2P (Person-to-Person)
Sender	Software/Application	Human (from phone)
Recipient	Human	Human
Volume	High (thousands-millions)	Low (individual)
Purpose	Business communication	Personal communication
Examples	OTP codes, alerts, marketing	Texting friends, family
Carrier treatment	Special routing, fees	Standard SMS
Regulatory requirements	High (consent, compliance)	Low

Visual Comparison

A2P (Application-to-Person):
┌─────────────┐      ┌─────────────┐      ┌─────────────┐
│  Business   │ ───► │ SMS Gateway │ ───► │   Customer  │
│  Software   │      │   /API      │      │   Phone     │
└─────────────┘      └─────────────┘      └─────────────┘

P2P (Person-to-Person):
┌─────────────┐      ┌─────────────┐      ┌─────────────┐
│   Person    │ ───► │   Carrier   │ ───► │   Person    │
│   Phone     │      │   Network   │      │   Phone     │
└─────────────┘      └─────────────┘      └─────────────┘

How A2P SMS Works

The Technical Flow

1. Business Application
   │
   ▼
2. SMS API Provider (Twilio, MessageBird, etc.)
   │
   ▼
3. SMS Aggregator/Gateway
   │
   ▼
4. Carrier Network (AT&T, Verizon, T-Mobile)
   │
   ▼
5. Recipient's Mobile Device

Key Components

Component	Role	Examples
Business Application	Triggers messages	CRM, e-commerce platform, app
SMS API	Interface for sending	Twilio, Vonage, Plivo
Aggregator	Routes to carriers	Direct connections or resellers
Carrier	Final delivery	AT&T, T-Mobile, Verizon

Key Use Cases for A2P SMS

A2P messaging serves critical business functions across industries.

1. Two-Factor Authentication (2FA/OTP)

The largest A2P use case by volume:

Your verification code is: 847291
Do not share this code. It expires in 10 minutes.

Why SMS for 2FA:

Works on any phone (no app required)
Universal reach
Users understand the flow
Fast delivery (seconds)

Industry	2FA Adoption
Banking/Finance	95%+
Healthcare	80%+
E-commerce	70%+
Social Media	90%+

2. Transactional Notifications

Messages triggered by customer actions:

Order Confirmation:

Your order #45231 is confirmed!
Total: $89.99
Track: example.com/track/45231

Shipping Update:

Your package is out for delivery.
Expected arrival: Today by 6 PM
Driver: John (555-0123)

Appointment Reminder:

Reminder: Dr. Smith appointment
Tomorrow at 2:30 PM
Reply C to confirm, R to reschedule

3. Marketing Campaigns

Promotional messages to opted-in subscribers:

FLASH SALE: 40% off everything today only!
Use code FLASH40. Shop: example.com/sale
Reply STOP to opt out

Learn more about running effective campaigns in our Bulk SMS Guide.

4. Alerts and Emergency Notifications

Time-critical information:

Fraud Alert:

ALERT: Unusual activity on your card ending 4521.
Did you authorize $299 at BestBuy?
Reply YES or NO

Service Outage:

[ServiceName] Status: Scheduled maintenance
tonight 2-4 AM EST. Brief interruption expected.

Emergency:

EMERGENCY ALERT: Severe weather warning.
Seek shelter immediately. Details: alert.gov/123

A2P Message Types Comparison

Type	Consent Required	Timing	Volume	Example
OTP/2FA	Implicit (user-initiated)	Immediate	Per-action	Login codes
Transactional	Service agreement	Event-triggered	Medium	Order updates
Marketing	Explicit opt-in	Scheduled	High	Promotions
Alerts	Varies	As-needed	Low	Fraud warnings

A2P SMS Delivery Channels

Short Codes (5-6 digits)

Feature	Value
Throughput	100-500 msg/sec
Cost	$500-1,000/month + per-message
Setup time	8-12 weeks
Best for	High-volume campaigns

Example: Text “JOIN” to 12345

10DLC (10-Digit Long Code)

Feature	Value
Throughput	1-10 msg/sec (varies by trust score)
Cost	$2-15/month + per-message
Setup time	1-2 weeks
Best for	Low-medium volume, local business

Example: Messages from (555) 123-4567

Toll-Free Numbers

Feature	Value
Throughput	3-10 msg/sec
Cost	$2-10/month + per-message
Setup time	1-2 weeks
Best for	Customer service, support

Example: Messages from 1-800-555-0123

Sender ID (Alphanumeric)

Feature	Value
Throughput	Carrier-dependent
Cost	Per-message only
Two-way	No (cannot receive replies)
Best for	Branding, international

Example: Messages from “YourBrand”

A2P SMS Pricing

Typical Cost Structure

Cost Type	Range
Per-message (US)	$0.007-0.05
Per-message (International)	$0.02-0.15
Platform fee	$0-100/month
Number rental	$1-1,000/month
Carrier fees (10DLC)	$0.003-0.005/msg

Volume Pricing Example

Monthly Volume	Typical Rate
1-10,000	$0.03-0.05
10,001-100,000	$0.02-0.03
100,001-1M	$0.01-0.02
1M+	$0.007-0.01

A2P SMS Regulations

United States

Regulation	Requirement
TCPA	Prior express consent for marketing
CTIA Guidelines	Opt-out support, sender identification
10DLC Registration	Brand and campaign registration required
CAN-SPAM	Applies to SMS (opt-out, identification)

Compliance Checklist

Obtained explicit consent for marketing messages
Documented consent with timestamp
Include business identification in messages
Provide opt-out in every marketing message
Honor STOP requests within 24 hours
Registered 10DLC campaigns (US)
Compliant with industry regulations (HIPAA, PCI, etc.)

A2P SMS Providers

Major Platforms Comparison

Provider	Strength	Starting Price
Twilio	Developer-friendly API, documentation	$0.0079/msg
Vonage (Nexmo)	Global reach, enterprise features	$0.0065/msg
MessageBird	European presence, omnichannel	$0.006/msg
Plivo	Cost-effective, reliable	$0.005/msg
Sinch	Carrier-grade, global	Custom
AWS SNS	AWS integration, scale	$0.00645/msg
Bandwidth	Direct carrier connections	Custom

Choosing a Provider

Requirement	Look For
High volume	Direct carrier connections, volume pricing
Global reach	Multiple country coverage, local numbers
Developers	Strong API, SDKs, documentation
Enterprise	SLAs, dedicated support, compliance tools
Budget	Competitive per-message rates

A2P SMS Metrics

Key Performance Indicators

Metric	Formula	Benchmark
Delivery Rate	Delivered / Sent × 100	>98%
Latency	Time to deliver	<5 seconds
Conversion Rate	Actions / Delivered × 100	2-10%
Opt-out Rate	Opt-outs / Delivered × 100	<2%
Cost per Conversion	Total Cost / Conversions	Varies

Industry Benchmarks

Message Type	Delivery Rate	Response Rate
OTP/2FA	99%+	N/A
Transactional	98%+	10-30% (if action needed)
Marketing	97%+	5-15%
Alerts	98%+	20-40%

A2P vs P2P: Why It Matters to Carriers

Carriers treat A2P differently because:

Spam Prevention

P2P traffic from a single phone sending thousands of messages is spam. A2P is expected to be high-volume from legitimate businesses.

Revenue

A2P messaging generates significant carrier revenue through:

Higher per-message fees
Registration fees (10DLC)
Throughput tiers

Network Management

A2P traffic is routed through dedicated infrastructure to:

Ensure delivery reliability
Apply spam filtering
Manage network load

Compliance

Registered A2P senders are accountable for their messages, reducing spam complaints.

Common A2P SMS Mistakes

Mistake	Consequence	Solution
Sending without consent	TCPA fines ($500-1,500/msg)	Proper opt-in flows
Using P2P for A2P	Message blocking	Register as A2P
No opt-out included	Carrier complaints, blocking	Include STOP in every message
Poor sender ID	Low trust, filtering	Use verified numbers
Wrong message type	Compliance issues	Match content to consent

Conclusion

A2P SMS is the engine behind business mobile communication—from the OTP codes that secure your accounts to the delivery notifications that track your packages. As businesses increasingly rely on mobile engagement, A2P messaging continues to grow despite the rise of alternative channels.

Key takeaways:

A2P = Application-to-Person: Software sends to humans
P2P = Person-to-Person: Humans send to humans
Primary uses: 2FA, transactional, marketing, alerts
Compliance is critical: TCPA, CTIA, 10DLC registration
Choose the right channel: Short codes, 10DLC, or toll-free based on volume

Ready to launch your A2P campaigns? Start by optimizing your messages with our free SMS Character Counter.