Deliverability
How to choose a messaging channel by country
WhatsApp, Telegram, Viber, LINE, Zalo, RCS or SMS? How to pick a channel per country for messages customers expect, and measure it on your own base.
6 min read
Articles tagged “SMS”
5 articles.
Deliverability
RCS capability check: what it tells senders before they send
What an RCS capability check tells you before sending, iPhone support, RCS vs SMS fallback, what RBM is, and a decision table with bulk API examples.
7 min read
Deliverability
SMS delivery receipts vs HLR lookup: before or after you send
A delivery receipt reports what happened after you sent an SMS. An HLR lookup asks the network before you send. What each can see, miss and cost.
7 min read
Deliverability
WhatsApp OTP vs SMS OTP: cost per verified user, with a calculator
WhatsApp authentication rates vs SMS prices by country, the October 2026 changes, and a calculator for cost per verified user including SMS fallback.
7 min read
Deliverability
Why SMS messages aren't delivered: a cause tree with fixes
A cause tree for undelivered SMS: invalid numbers, unreachable phones, wrong line types, carrier filtering and handsets, with a fix for each.
7 min read
