This week, Max's US-based marketing agency officially crossed more than 1.2 million messages processed through inst8 since joining on 15 March 2026. The agency is now running 290 active SIM cards across 152 devices, serving 20 client sub-accounts.
Here's how he got there, and why a few features we built along the way made the difference.
The problem with agency-scale SMS.
Max runs a US marketing agency that handles SMS for a roster of small and mid-market clients. Every client wants the same thing: high-volume, conversational outbound that drives actual replies, not just deliveries that vanish into carrier filters.
But conventional SMS at that scale runs into a wall fast. Shortcodes and 10DLC come with throughput caps, expensive per-message rates, and brand-registration headaches that don't scale across dozens of client brands. Twilio and similar gateways are technically capable but financially brutal once you're sending hundreds of thousands of messages a month, and their carrier filtering routinely strips out the kind of high-volume messaging Max's clients depend on.
Worst of all, the moment a number gets flagged, that client's pipeline can stall overnight. Replacement and re-warmup take days. For an agency, every flagged number is a dropped commitment to a client.
“I'd burned through three different platforms before finding inst8. Every time things started working, the system would crack under volume. Or the price would. Or both.”
Why inst8.
Max found inst8 in March looking for a way to run real SIM-based SMS at agency scale: actual phone numbers on actual carriers, not virtual longcodes routed through aggregators. He was sending live traffic the same day he signed up. His very first message went out on 15 March at 7:41 AM, within ninety minutes of account creation.
What he found was a model designed around the way agencies actually work:
- Real SIMs on consumer carriers, which receive and reply like any normal mobile number. No shortcode registration, no 10DLC brand approval.
- HighLevel integration out of the box, so each client's HighLevel sub-account routes outbound and inbound through its own dedicated number.
- Multi-tenant architecture, so adding a new client means adding more SIMs, not standing up new infrastructure.
- Per-SIM throughput and rate controls that let him push hard on numbers that are performing and back off on ones that aren't.
The numbers.
Seventy-eight days in, the headline metrics tell the story. The agency is running 290 SIMs across 152 devices, processing more than 1.2 million messages at a 98.9% delivery success rate across five different carriers.
Anyone can push a lot of messages. Far fewer can push that many while keeping deliverability that clean.
The role of SIM Health.
The honest version of any high-volume SMS operation is this: numbers degrade. Carriers watch traffic patterns closely, and the difference between an agency that scales and one that stalls is how quickly degraded numbers are detected and quarantined before they drag the whole fleet down.
When Max joined, we'd been building an early version of our SIM Health features for high-volume use. He became one of our most important collaborators in shaping what those features eventually became. Real-time monitoring of per-SIM deliverability, automatic protective limits, and surfacing of numbers that are quietly going bad were all tested, broken, and iterated on at his scale before they shipped to everyone else.
His account now runs SIM Health continuously across all 290 numbers, and that 98.9% delivery rate is, in large part, what those features were built to protect.
“The health monitoring is what lets me actually sleep. I can scale this thing without spending half my week chasing down dead numbers.”
What's next.
Max isn't slowing down. His SIM count has grown from zero at signup to 290 today, and his daily volume is still trending up. The agency's roadmap is clear: more clients, more numbers, more replies.
For inst8, the takeaway is just as clear. Max is proof that the platform works at the scale agencies actually need, and a reminder that the features we build for the messy edges of high-volume messaging are exactly what makes that scale possible.
“If you'd told me on day one I'd hit a million messages in two months, I'd have laughed. Now I'm wondering how fast we get to ten.”