High-Volume SIM SMS Routing

I’m preparing a large-scale SMS distribution project that will run on a bank of GSM modems. All traffic will be plain SMS messages and the system must comfortably handle continuous, high-throughput volumes while keeping individual SIM usage balanced and compliant.

The core I need from you is the full routing and SIM management layer—everything required to plug multiple modems in, inject message batches, and watch them fly out without bottlenecks. Bulk messaging is the everyday workload, so the architecture has to queue efficiently, rotate SIMs, and recover gracefully from any network hiccups. I also want native support for scheduled send-outs to time campaigns precisely, plus real-time delivery reports so I can monitor success ratios and react immediately if carriers start filtering.

Please plan for:

• Bulk Messaging
• Scheduled Sendouts
• Delivery Reports

If you already have experience tuning AT-command stacks, pooling SIMs, or building custom SMSC connectors, that’s exactly the kind of know-how I’m after. Code can be in any robust language (Go, Python, Java, C# are all fine); just keep it modular so future modem models or additional SIM banks can drop in with minimal tweaks.

At hand-over I’ll test by pushing a 10 k-message batch with mixed schedules and will sign off once throughput, scheduling accuracy, and delivered receipts match the agreed benchmarks.