Large-scale SMS Promotion Delivery

I have a single English-language promotion that must reach between 300,000 and 700,000 mobile numbers in Canada and/or the United States. The contact list is cleaned, opt-in, and ready to load, and every recipient will receive exactly the same message only thing that changes is reference code in msg-just a short line of copy plus a phone number, no links or tracking URLs.
My priority is deliverability. Whether you use direct carrier routes, an SMPP gateway, SIM-card pools, or another proven method is up to you; what matters is that the texts actually arrive at scale without being throttled or flagged as spam. If you already run high-throughput platforms such as Twilio, Plivo, Infobip, GoHighLevel, or custom GSM modem banks, please tell me.
To keep us both aligned, I'll need:
• Secure import of the CSV lead file I provide.
• Intelligent batching or throttling so carriers don't block the traffic.
• Live or end-of-day delivery stats (sent, delivered, failed).
• Confirmation that the sending method complies with Canadian and U.S. SMS regulations.
• A clear timeline-once everything is set up, l'd like the blast completed within a few days.
If you can achieve the highest possible delivery rate and supply transparent reporting, let's get started.