Problem framing and SMS Gateway scope
What an A2P SMS gateway is and why carrier routing defines it
Problem framing and SMS Gateway scope
An SMS gateway is the system that lets applications send text messages to phones at scale: a developer calls an API and we deliver an A2P (application-to-person) SMS through the carrier network. The fact that defines the architecture is carrier routing and delivery receipts. We do not own the last hop, mobile carriers deliver the SMS to the handset, so our job is to accept a message, choose the best carrier route to its destination, hand it off over a carrier connection, and reconcile the asynchronous delivery receipt (DLR) the carrier sends back. The gateway lives between the application and a fleet of carrier and aggregator connections.
The spine is therefore: an API that accepts a send idempotently, message segmentation for long texts, least-cost routing that picks a carrier route per destination, carrier connections (typically SMPP bindings with per-binding throughput limits), a delivery state machine driven by DLRs, webhooks that surface delivery status to the customer, per-tenant and per-binding rate governance, and an event ledger for billing. State the framing up front: an SMS gateway is a routing-and-reconciliation layer in front of carrier connections, and the hard parts are least-cost routing, DLR reconciliation, and respecting per-binding throughput.
Key Highlights
- •An A2P SMS gateway: applications send texts to phones at scale via carriers
- •We do not own the last hop; carriers deliver to the handset
- •Choose a carrier route, hand off over SMPP bindings, reconcile the DLR
- •Spine: idempotent API, segmentation, least-cost routing, DLR state machine, webhooks
Section Rescue Kit
Buzzwords to use:
Safe statements:
- "An SMS gateway is a routing-and-reconciliation layer in front of carrier connections."
- "The hard parts are least-cost routing, DLR reconciliation, and per-binding throughput."