Guides for messaging in India
Practical guides on SMS, OTP, WhatsApp and voice in India, covering DLT, routing and pricing, from the people who run the platform.
Latest guides
— IVR and numbersThe 1600 number mandate: what regulated callers in India need to know
Commercial banks had to call from 1600 numbers from January 2026; NBFCs, insurers and SEBI firms follow in phases. Who must move, by when, and how.
· 7 min read
— SMSWhy DLT templates get rejected, and how to write ones that pass
Why SMS content templates fail DLT review in India: category mismatches, variable mistakes, header conflicts, and a drafting process that passes first time.
· 10 min read
— IVR and numbersIVR menu design: getting callers to an answer without the maze
Callers want an outcome, not a menu. How to design IVR menus that resolve calls: language first, shallow trees, plain prompts, and always a way out.
· 8 min read
— OTP and verificationOTP not delivered? A troubleshooting checklist for Indian SMS routes
Where SMS OTPs fail in India (template scrubbing, wrong header categories, handset quirks) and how to instrument the flow before your users notice.
· 9 min read
— Voice broadcastingPromotional calls in India: the TRAI rules to know before you dial
Outbound voice campaigns in India run under TRAI telemarketing rules: DND scrubbing, registered senders, calling windows and consent. What compliance means.
· 8 min read
— WhatsApp and RCSRCS vs SMS: what actually changes, and what doesn't
RCS adds a verified sender, media and buttons to carrier messaging; SMS keeps universal reach. How the two differ in India, and why campaigns need both.
· 8 min read
— SMSSMS character limits: GSM-7, Unicode, and why one symbol can triple your bill
One SMS holds 160 GSM-7 or 70 Unicode characters; split messages drop to 153 or 67 per segment. See which symbols, like ₹ and emoji, double your bill.
· 9 min read
— IVR and numbersToll-free vs virtual numbers: which number should your business publish?
1800 toll-free numbers and virtual numbers do different jobs — who pays for the call, what callers read into the number, and how routing and tracking differ.
· 8 min read
— Voice broadcastingWriting a voice broadcast script people stay on the line for
A voice broadcast wins or loses attention in seconds. How to structure the script (identity first, one message, one keypress action) and record it well.
· 8 min read
— WhatsApp and RCSWhatsApp Business app vs API: when the free app stops being enough
The WhatsApp Business app suits one number and one pair of hands. What the API adds (broadcasts, team inboxes, automation) and when it's time to move.
· 8 min read
— WhatsApp and RCSWhatsApp opt-in rules: consent that keeps your broadcasts landing
Meta requires opt-in before a business messages customers on WhatsApp. What counts as consent, how Indian businesses collect it, and how it protects delivery.
· 8 min read
— OTP and verificationWhatsApp OTP vs SMS OTP: choosing a verification channel in India
SMS reaches every handset; WhatsApp authentication templates add one-tap codes and a different cost model. How the two compare, and when to sequence both.
· 8 min read
— SMSTransactional vs promotional SMS in India: which route to use
Transactional, service, and promotional SMS in India follow different DLT rules, hours, and headers. Here's how to tell them apart and route each one correctly.
· 8 min read
— SMSHow to choose a bulk SMS provider in India: a checklist
Price is only one factor. A practical checklist for choosing a bulk SMS provider in India — DLT, deliverability, channels, support, and the questions to ask.
· 7 min read
— OTP and verificationSMS OTP best practices: expiry, rate limits, and auto-read
How to build a secure, low-friction SMS OTP flow in India: code length, expiry, attempt caps, voice fallback and Android auto-read, without storing codes.
· 8 min read