Building production-grade AI phone agents since 2023. From Fortune 500 integrations to open-source telephony deployments — we ship systems that scale.
Trusted by industry leaders across energy, healthcare, retail, sports, and tech to build mission-critical voice AI systems.
End-to-end implementation from prompt engineering to production telephony infrastructure.
Custom LLM-powered phone agents built on Retell AI — inbound, outbound, and blended workflows with enterprise-grade reliability.
SIP trunking, PSTN connectivity, Jambonz deployments, Twilio/Telnyx integrations — carrier-grade infrastructure that scales.
Deep integrations with Salesforce, HubSpot, GoHighLevel, Zoho — your AI agents update records, book appointments, and sync data in real time.
Systematic prompt development, conversation design, and quality assurance testing to maximize call success rates.
Build and deploy under your brand. We act as your technical team — you take the credit. NDA and white-label agreements available.
Zapier, Make.com, N8N — connect your voice agents to any tool in your stack with battle-tested automation pipelines.
Years of hands-on experience across the voice AI and enterprise telephony stack.
As a Certified Elite Retell AI Partner, we've built more Retell deployments than almost anyone. We know the platform's capabilities and limits — and how to architect around both.
Open-source, enterprise-grade telephony infrastructure. We deploy, configure, and maintain Jambonz at scale — giving you carrier-grade call handling with full data sovereignty.
Jambonz gives enterprises full control over their telephony stack. No vendor lock-in. No per-minute charges. Just powerful, flexible SIP infrastructure you own.
Explore Jambonz Solutions →We've been in the telephony trenches since before voice AI was a thing. That experience shows.
Real production deployments at scale — not demo environments. We've seen what breaks at volume and built systems to handle it.
We were building telephony automation before "voice AI" was a category. That institutional knowledge is your competitive advantage.
The highest Retell AI partner designation. Fewer than a handful of companies globally hold this status.
"Call Sandwich built our entire inbound AI agent stack. The integration with our CRM was seamless and the call quality exceeded our expectations from day one."
"Their Jambonz expertise saved us six figures in carrier costs. The migration was smooth and we now have full control over our telephony infrastructure."
"We tried two other vendors before Call Sandwich. They understood Retell AI at a level nobody else could match — our agent performance went from 60% to 94% success rate."
Whether you're building your first AI agent or scaling to millions of calls, we've got the infrastructure and expertise to make it happen.