Signal & Syntax · Messaging and A2P

What Is an SMS Grey Route?

A grey route delivers A2P SMS through a channel priced for person-to-person traffic. Grey routes skip the operator's A2P termination rate.

Also calledgray route · SIM farm route · bypass route

Grey Route in Practice

Grey routes run through SIM farms or unofficial interconnects. Operators detect grey traffic with SMS firewalls and block the traffic without warning. On a grey route, sender IDs and receipts come from the bypass. The terminating operator never sees the sender.

Related Terms

A2P messaging A2P (application-to-person) messaging is SMS sent by software to a mobile user. P2P messaging P2P (person-to-person) messaging is SMS sent from one handset to another by a person. SMS aggregator An SMS aggregator connects to a large set of operators and resells SMS routes. Delivery receipt A delivery receipt (DLR) is the status report an operator returns for each SMS.

Read the Guide

Guide

How A2P SMS Reaches a Handset

The path from an API call to a delivery receipt. Read the guide →

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