Exhibit A
Climb from keyword idea to a live short code
- Tier 1Tier 1: Idea and keyword (below the current tier)Day 0Day 0
- Tier 2Tier 2: Code leased (below the current tier)DaysDays
- Tier 3Tier 3: Programme brief (below the current tier)SubmittedSubmitted
- Tier 4Tier 4: Carrier review (below the current tier)WeeksWeeks
- Tier 5Tier 5: Provisioned (below the current tier)Per carrierPer carrier
- Tier 6Tier 6: Live (current)~100 msg/s~100 msg/s
Tier 6 · Live
~100 msg/s
Why: Tests pass on every network
Traffic flows at short-code speed — around 100 messages per second is a common US starting point (illustrative; set per programme).
Move 7 of 7: climbs to tier 6, Live (~100 msg/s). Tests pass on every network
What is an SMS short code?
A short code is a five- or six-digit phone number (some countries use three, four or eight digits) that businesses use for application-to-person SMS. Unlike an alphanumeric sender ID, a short code is a real number customers can text, so it suits two-way traffic: keyword campaigns ("text WIN to 5xxxx"), opt-ins and opt-outs with STOP, polls, contests and inbound lead capture. Short codes are national: each country's numbering plan allocates its own, and a code works only on that country's networks.
In the US and Canada, short codes are leased from a central registry — in the US, the Common Short Code Administration (CSCA) — as random numbers or chosen vanity numbers, and each carrier then approves the messaging programme before it goes live. That vetting is why US short codes carry the highest throughput and most predictable delivery of any sender type, and why approval often takes weeks. In other countries operators allocate short codes themselves. In India, five-digit codes are owned by operators and are commonly shared across many brands by keyword, mostly for inbound responses, while outbound commercial SMS must still come from a DLT-registered header.
The neighbouring options are the long code — an ordinary-length number that is cheaper and more personal but slower and, in the US, subject to A2P 10DLC registration — and the alphanumeric sender ID, a one-way brand label. In carrier terms, the keyword a customer texts in is a mobile-originated (MO) message and your reply is mobile-terminated (MT); MO vs MT messages explains why the two are routed and priced differently. On WhatsApp, the equivalent of a short-code keyword is a click-to-chat link or QR code that opens a chat with a prefilled message.
Key takeaways
- A short code is a five- or six-digit number for two-way business SMS: keyword campaigns, opt-ins, polls and high-volume alerts.
- Short codes work only inside the country that issued them; international users need another channel.
- In the US, codes are leased from the Common Short Code Administration and approved carrier by carrier, often over 8–12 weeks.
- In India, five-digit codes are owned by operators and usually shared by keyword for inbound campaigns, while outbound commercial SMS uses a DLT header.
- The WhatsApp counterpart of "text a keyword to a short code" is a click-to-chat link or QR code with a prefilled message.
How does an SMS short code work?
Choose dedicated or shared, random or vanity
A dedicated code belongs to one brand; a shared code splits traffic by keyword between brands, which is common in India. Vanity codes spell or repeat something memorable and cost more than random ones.
Lease the code or the keyword
In the US, lease the code from the CSCA for recurring terms. In India, rent a keyword on an operator-owned shared code from an aggregator, usually per keyword per year, or arrange a dedicated code with the operators.
Write the programme brief
Describe the campaign, the opt-in call-to-action, message frequency, sample messages and the HELP and STOP replies. Carriers compare the brief with the live advert or web page.
Carrier approval and provisioning
Each carrier reviews the brief and then provisions routing for the code. In the US the end-to-end process is often quoted at 8–12 weeks; test inbound and outbound on every network before launch.
Run keyword traffic
Inbound messages carry the keyword; your application routes by keyword, replies within seconds, stores the opt-in and honours STOP immediately.
Example: A Diwali contest for an Ahmedabad sweets chain
An Ahmedabad sweets chain prints "SMS MITHAI to our five-digit short code" on its festive boxes, using a keyword rented on an operator-owned shared code. Each text arrives as an MO message carrying the keyword and the sender's number; the chain's system replies within seconds with a contest entry number and a WhatsApp click-to-chat link for customers who want their voucher there. Follow-up messages go out from the chain's DLT-registered header with a registered template, not from the short code. Because every box batch uses a different keyword — MITHAI for boxes, SWEET for the counter poster — the chain sees which placement drove each entry, and anyone who texts STOP is suppressed across SMS and WhatsApp.
Why does an SMS short code matter?
A short code turns a print ad, a TV spot or a sticker on a pack into a measurable response channel: customers text one memorable keyword and you capture the lead, the consent or the vote, attributed to the ad that carried it. In markets such as the US it is also the sender of choice for very high-volume alerts and OTPs, because carriers pre-approve the programme. The trade-offs are cost, lead time and a single-country reach — which is why many Indian businesses now run the same keyword mechanics on WhatsApp.
Common mistakes with an SMS short code
Advertising before every carrier is live
If one network has not provisioned the code, its customers' texts fail and the campaign looks broken. Launch the advert only after inbound and outbound tests pass on every major operator.
Weak opt-in and STOP handling
Carriers audit programmes, and a STOP that does not work immediately can get the code suspended. Answer HELP and STOP automatically and keep a record of every opt-in.
Generic keywords on a shared code
On a shared code, words like OFFER or WIN are often taken or confusing. Choose a brand-specific keyword and check its availability with the aggregator before printing anything.
Expecting a short code to work abroad
A short code exists only in its own country's numbering plan. Customers on foreign SIMs cannot text it, so give them a WhatsApp link or a full international number instead.
Using the short code as the outbound sender in India
Commercial messages to customers must go from a DLT-registered header with a registered template. Use the short code to receive keywords and send follow-ups through your DLT setup.
Best practices for an SMS short code
- Pick keywords that survive autocorrect: short, single words with no punctuation.
- Reply to every keyword within seconds — the reply is both your confirmation and your proof of opt-in.
- Print a WhatsApp QR code next to the short code for customers who prefer chat.
- Give every advert or placement its own keyword so responses are attributable.