Our 3G/4G SMS gateway is still running. Here is what we'd change.
By Scott Li ·
Our industrial-grade SMS gateway is still in production at SG enterprise clients. The hardware estate has aged. The cellular generation has not. Here's the honest update.
Our industrial-grade SMS gateway — 8-to-32 channel modem pools, JSON HTTP API, encrypted contact storage, private deployment — has been in production for SG enterprise clients since around 2018. The product is still alive. A few real things have changed.
What still works
- Local hardware in the customer’s data centre. For clients who want zero third-party exposure of mobile numbers, this is still the cleanest answer. We deploy and they own it.
- HTTP API + JSON. Legacy systems integrate easily. ERP / quotation / appointment-reminder systems we build still call this gateway.
- Auto-extract numbers from text + duplicate removal. Boring. Useful. Has not aged.
What needs updating
1. 3G is gone, 4G is fading
3G is fully decommissioned by SG operators. The hardware that supported 3G fallback is now scrap. New deployments are 4G-only on hardware that will receive 5G modules in 2026–2027.
If you are reading this and you have a 3G/4G modem pool that hasn’t been touched in years: please check it. It may be silently failing on the 3G half.
2. Two-way SMS regulation has tightened
IMDA’s tightening of unsolicited-SMS rules and the move to authenticated SenderIDs has changed what’s possible from a programmable gateway. We now require:
- A registered SenderID for any outbound campaign.
- Explicit opt-in records, kept per recipient.
- An auto-honour for STOP / unsubscribe at the gateway level (this was already in our product; we now treat it as non-optional).
3. WhatsApp and RCS are mostly the better default
For most customer-communications use cases — appointment reminders, OTP, transactional notifications — WhatsApp Business API or RCS is the better default. SMS is the fallback lane.
We integrate WhatsApp for clients that want it. The SMS gateway sits behind WhatsApp as the fall-through for recipients without WhatsApp or for jurisdictions where WhatsApp doesn’t cover.
4. The agent-era footnote
A few clients have asked whether an agent should write the SMS body. Generally: no. SMS is 160 characters, and most use cases are templated. Where the agent helps is the one upstream step — picking the right template based on a customer’s account context. The body itself stays templated for compliance and audit reasons.
Where the product page lives
The full feature spec lives under /services/ under “Secured SMS Gateway.” This is the studio note that comes with it.
The gateway is still running, still on a private rack at multiple SG enterprise clients, doing exactly what it was deployed to do.
— Scott Li, wGrow