How it works
Carriers distinguish two broad kinds of text traffic:
- P2P (person-to-person): an individual texting another individual from a phone.
- A2P (application-to-person): a business sending texts through software, whether automated (a reminder sent by a booking system) or typed by a staff member in a team inbox.
The second point surprises people. A rep typing a reply by hand in a CRM is generally still sending A2P traffic, because the message goes out through a business platform on a business number.
In the US, A2P traffic is sent over one of three main number types:
- 10DLC: standard local numbers, with brand and campaign registration.
- Toll-free numbers: 800-style numbers, with a toll-free verification process.
- Short codes: 5–6 digit numbers, typically for high-volume programs, with their own application process.
Each has different setup steps, throughput and costs, and carriers’ requirements change.
Example
A veterinary clinic sends three kinds of texts: appointment reminders from its scheduling system, replies typed by front-desk staff in a shared inbox, and occasional vaccine-due reminders. All three are A2P. The clinic registers its business and a campaign covering appointment reminders and customer care on its local number, and collects consent from pet owners when they book.
A2P vs. 10DLC
These terms are often used together (“A2P 10DLC”), but they aren’t the same:
- A2P describes what kind of messaging it is.
- 10DLC describes which kind of number is used to send it, and the registration attached to it.
All 10DLC business texting is A2P; not all A2P texting uses 10DLC.
Why it matters for messaging teams
Once a team moves texting off personal phones and into shared software, its messages become A2P traffic with registration and consent obligations. That’s a good thing for accountability, but it means planning: register before you send, describe your use case accurately and keep opt-in records.
Common mistakes
- Assuming manual, one-to-one replies are exempt from A2P rules.
- Using a personal cell number for business texting at scale.
- Mixing marketing into a campaign registered for customer care.
- Ignoring opt-out replies like STOP.
This is general information, not legal advice; check with your provider or counsel. inChat’s SMS channel is in development as a launch channel.