What Is an SMS Gray Route? Types, Risks and Safer Alternatives

Introduction: SMS Gray Route

SMS is one of the most reliable ways for businesses to deliver OTPs, alerts, reminders, and notifications. But here’s the thing—not all SMS travel through legal or approved paths. A large portion of global A2P traffic still uses what the telecom world calls an SMS gray route, a low-cost but risky method of message delivery.

Understanding how gray routes work is critical if your business sends messages to Bangladesh, Brazil, Mexico, Chile, UAE, Malaysia, Australia, Germany, India, or any market with high SMS filtering. Choosing the wrong SMS route leads to delays, fraud exposure, blocked messages, brand damage, and legal issues.

This guide explains everything—from how gray routes work to how they evolved, why they still exist, how operators detect them, and why businesses must avoid them.

What is an SMS gray route?

An SMS gray route is an unauthorized or semi-legal message delivery path where A2P (Application-to-Person) traffic is disguised as P2P (Person-to-Person) traffic to bypass operator termination fees. It is cheaper, but unstable, often illegal in some regions, easily blocked by telecom firewalls, and harmful for OTP message or critical message delivery.

What Is an SMS Route? (Direct vs Indirect)

Every SMS travels through a route, the delivery path connecting your SMS platform to the recipient’s operator. These routes determine delivery speed, security, reliability, and compliance.

There are two broad categories:

1. Direct Routes (Operator-Approved A2P Routes)

Direct routes connect your SMS provider directly to mobile operators in the destination country.

They offer:

• High delivery rates

• Near-instant OTP speed

• Legally approved routing

• Secure data handling

• Real DLR (delivery reports)

• Full traceability

• High uptime and stability

Direct routes may require:

• Sender ID registration

• Template approval

• Content restrictions (political, gambling, etc.)

• Time-based sending restrictions

Direct routes cost more, but they are the only reliable option for critical messages.

2. Indirect Routes (One-Hop, Two-Hop, Multi-Hop)

Indirect routes involve intermediaries. They are cheaper but:

• Lower delivery consistency

• Less control

• More filtering by operators

• Higher risk of blocking

One major category of indirect routes is the SMS gray route.

What Exactly Is an SMS Gray Route?

An SMS gray route is an A2P delivery method that uses unapproved signaling paths—often P2P SS7 channels or multi-hop indirect routes—to avoid operator termination fees, regulatory requirements, and interconnect charges.

Key characteristics include:

• A2P traffic disguised as P2P

• No commercial agreement between operators

• No sender ID verification

• No traceability or guaranteed delivery

• Prone to blocking and delays

Gray route SMS is widely regarded as telecom fraud in many countries.

Legal Status of SMS Gray Routes

An SMS gray route can be:

• Legal for the sender, but

• Illegal for the receiving operator

Why?

Because rules differ across countries.

Some nations classify gray routing as:

• Abuse of telecom infrastructure

• Fraudulent avoidance of interconnect fees

• Violation of data protection laws

• Unauthorized cross-border signaling

Using gray routes may expose businesses to:

• Fines

• Service suspension

• Compliance audits

• Reputational damage

The History of SMS Gray Routes (How It All Started)

SMS was introduced in the early 1990s, running on the SS7 signaling network, originally designed for P2P text messages only.

As SMS popularity grew:

• Network aggregators began exchanging messages globally

• Instead of genuine P2P messages, they started injecting A2P messages from computers

• Operators noticed one-way traffic patterns and message bounces

• Huge volumes of unbilled traffic led to revenue loss

• Spam increased

These unauthorized A2P messages became known as SMS gray routes.

A2P Gray Routes and SS7 Misuse

SS7 allows operators to exchange messages during roaming.
Gray route providers misuse SS7 by:

• Injecting A2P traffic into P2P signaling

• Using foreign global titles (GT) to hide origin

• Bypassing interconnect fees

• Hiding message patterns from operators

This method is one of the most common sources of illegal gray routing.

How Big Is the SMS Gray Route Problem? (Industry Statistics)

Telecom revenue leakage due to gray routes is huge:

• 65% of global A2P SMS traffic used gray routes in 2015

• Expected to drop only to 19% with better detection

• Operators will lose $62 billion globally over the next several years

• A typical MNO loses $2 million per year to unmonetized gray traffic

• If properly billed at $0.06 per SMS, operators could earn $17.3M annually

These numbers explain why operators aggressively block gray routes today.

Types of SMS Gray Routes (Technical Classification)

Gray routes fall into three main categories:

1. Telecom-to-Telecom Gray Routing

Two operators may have a roaming agreement for P2P messages.
Gray route providers exploit this by:

• Masking A2P messages as P2P

• Sending bulk messages that appear domestic

• Creating one-way traffic instead of natural 1:1 flow

This is called GT (Global Title) misuse.

2. Aggregator-Based Gray Routes

A telecom operator or aggregator sends messages through a local market SMPP aggregator with cheaper rates.
This bypasses official interconnect fees and leads to:

• Revenue loss for the receiving operator

• Lower delivery reliability

• Inconsistent message performance

3. SIM Box (SIM Farm) Gray Routes

Fraudsters use multi-SIM hardware with thousands of prepaid SIM cards:

• They send A2P SMS as if they were personal messages

• Operators constantly block these devices

• Delivery reliability is extremely low

• Illegal in many countries

This is one of the most common and dangerous forms of gray routing.

Wholesale Routes & SIM Routes (Indirect Gray Routes)

Wholesale Routes

Use roaming agreements between countries to forward messages cheaply.
Cons:

• Multiple hops

• Poor delivery rate

• Zero guarantees

• Frequent blocking

SIM Routes

Use prepaid SIM cards to send business traffic.
Cons:

• Always show random phone numbers as sender

• No reporting or traceability

• Quickly detected and shut down

Both fall under non-compliant indirect gray routes.

Problems Caused by SMS Gray Routes (Comprehensive List)

Gray routes might look cheap, but they cause significant damage:

1. Non-Compliance With Regulations

Messages may pass through countries with weak privacy laws, violating:

• GDPR

• Local data protection acts

• Cross-border data transfer rules

2. Legal Risks

Businesses may unknowingly break:

• Telecom laws

• Licensing requirements

• Messaging content regulations

3. Poor Deliverability

Gray routes lead to:

• Lower delivery rates

• Frequent message drops

• Higher bounce rates

4. Service Failures

Messages may never reach the destination due to:

• Blocked sender IDs

• Operator shutdowns

• Firewall filtering

5. Delivery Delays

OTP and time-sensitive messages often arrive late – or not at all.

6. Limited Features

Gray routes usually lack:

• Sender IDs

• Template approval

• Scheduling features

• True delivery reports

7. No Control or Metrics

Businesses cannot:

• Track delivery

• Monitor performance

• Validate message failures

• Measure campaign success

This destroys trust and reduces conversions.

How Operators Detect SMS Gray Routes Today

Telecoms now use advanced next-generation SMS firewalls that analyze incoming traffic patterns in real time.

Detection methods include:

• SS7 anomaly detection

• Behavior analysis

• Sender ID validation

• Pattern recognition

• Machine learning risk scoring

• Message velocity and throughput monitoring

• GT (Global Title) reputation databases

This modern system eliminates spam, SIM boxes, and unauthorized A2P traffic.

How to Identify if Your Provider Uses a Gray Route

Some warning signs:

• SMS pricing far below market average

• No support for sender ID in UAE, India, Malaysia

• No DLT compliance (India)

• Missing delivery reports

• OTP delays

• Provider avoids questions about operator connections

Ask your provider directly:

• “Do you use operator-approved A2P routes?”

• “Are delivery reports sourced from the operator?”

• “Do you follow GDPR and international compliance rules?”

If they cannot answer clearly, they are most likely using gray routes.

Global Regions Where Gray Routes Are Common

Pricing Comparison: Direct Route vs Gray Route

Cheap SMS is not cheap when customers never receive your message.

Why Businesses Must Avoid SMS Gray Routes

Here’s what gray routes really cost you:

• Failed OTPs

• Higher drop-offs

• Lost revenue

• Lower customer trust

• Poor campaign performance

• No legal compliance

• Zero delivery guarantees

For any brand that values trust, compliance, and message accuracy, gray routes are too risky.

Why Siratel Is the Safe Alternative (Direct Operator Routes)

Siratel provides:

• 100% operator-approved white routes

• High delivery success (98–99%)

• Real operator DLR

• Global SMS coverage across Bangladesh, Brazil, Mexico, Chile, UAE, Malaysia, Australia, Germany, India

• 24/7 monitoring

• Encrypted A2P routing

• Compliance with TRAI, GDPR, CTIA, and local regulations

• Instant Global OTP performance (1–3 seconds)

Siratel handles 3+ billion secure, compliant messages per month.

Final Summary – SMS Gray Route

An SMS gray route is an unapproved or semi-legal path used to deliver A2P SMS traffic by disguising it as P2P. While cheaper, gray routes cause delivery failures, delays, legal risks, privacy violations, and lost revenue. Businesses should always choose direct, operator-approved routes for safe and reliable message delivery.