Sr. Software Engineer (AI Voice & Messaging Agents)

Who We Are: At Keystone AI , we shape how the world connects. We're the global communications software company and Tier 1 network operator with global reach. The voice, messaging, and emergency services infrastructure behind the brands and apps you use every day. Because we own the network we build on, the problems you'll solve here are bigger, more complex, and more impactful. And as communications shifts to AI, we're the infrastructure layer making it possible. We call ourselves BANDmates because building something this big takes collaboration, different perspectives, and the freedom to bring your authentic self to the table. We're experts who speak like humans. Ready to build what's next? #JoinTheBand What we are looking for: We are seeking a Senior Software Engineer to join our Innovation Studio and help take ideas from early concepts through experimentation to shipping, revenue-generating products. This is an R&D and innovation role — but not the kind that ends with a whitepaper. Some weeks you're proving whether an idea even works; other weeks you're hardening a proven concept into something real customers can pay for. The mission decides. You'll be joining a small, high-caliber, T-shaped team that goes wherever the highest-priority work is, and your job is to help us turn promising bets into products that stand on their own. The Innovation Studio operates like a startup — backed by the infrastructure of a public company. We optimize for learning speed, not perfection. If you've spent your career inside enterprise release processes and that's where you're comfortable, this isn't the right fit. If you've been waiting for a team that experiments and ships at the pace of a startup but sits on top of a global communications network — keep reading. We’re looking for a senior IC, but we're more interested in how you work than your years of experience. If you're a strong mid-level engineer who sees yourself in the mindset below, we encourage you to apply. How You Work Matters As Much As What You Know. You lead by example, not management authority: What You Need: Engineering Fundamentals Are Non-Negotiable: You understand software design, system architecture, and why things break at scale — not because you read about it, but because you've built through it. Product Shipping Experience: You've built and launched products that real customers use — ideally in a startup or high-growth environment. Prototypes and POCs are a starting point, not the finish line. AI as a Force Multiplier, Not a Crutch: You've embraced AI development tools as a core part of how you work. You use AI to move faster while your experience and judgment ensure the output is sound. Deep Instincts Over Blind Trust: When AI generates code, you know whether it's good — and more importantly, you know when it's subtly wrong. Full-Stack Fearlessness: When you hit an unfamiliar domain, your instinct is to pick it up and move fast — using AI to operate across the full stack without sacrificing quality. This combination — strong fundamentals amplified by AI fluency — is a first-class requirement, not a nice-to-have. The Mindset: Comfortable in Ambiguity: Requirements are evolving, priorities shift weekly, and the roadmap is measured in weeks, not quarters. That energizes you. Entrepreneurial Instinct: You think about the product, not just the code. You care whether what you built actually moves the business forward. Pragmatic over Clever: You prefer boring technology that scales over shiny technology that breaks. You build guardrails and observability — then move fast inside them. Low Ego, High Ownership: You're here to move the mission forward, not to be the smartest person in the room. You'll pick up whatever task moves the team forward, whether it's glamorous or not. What You'll Do: Go Where the Mission Takes You: This is a T-shaped team. Backend services, frontend, infrastructure, data, AI pipelines — you go where the highest-priority work is. Role boundaries slow teams down; you ignore them. Take Ideas From Concept to Production: Explore whether an idea works, then build the layers that turn a proven concept into something real — the product surface, the APIs, the workflows, the operational glue, and everything in between. Close the Loop: Get your work in front of real users fast, whether that's a validation experiment or a shipped feature. You measure your work by what people do with it, not by what got merged. Lead Through Craft: You earn influence through code quality, smart trade-offs, and velocity — not title or tenure. You raise the bar through code review, design discussions, and pairing. Automate the Bottlenecks: When something in the dev cycle is slow or repetitive, your instinct is to script it, agent it, or eliminate it. You don't just build the product — you accelerate the system that builds it. Nice-to-Haves: Experience with real-time systems, voice/telephony, or conversational AI Hands-on experience with LLMs, agentic AI, prompt engineering, or model fine-tuning Experience building multi-tenant SaaS platforms or B2B / B2B2B products What Success Looks Like: Real outcomes, not demos: Ideas that become deployable, sellable products with paying customers. Weekly improvement loops: Shipping and learning from real user feedback every week. Operational confidence: Clear dashboards, measurable quality, fast incident response, and releases you can trust. Scale trajectory: Systems designed to grow without collapsing under their own complexity. Why This Role: Startup pace and ownership — without building distribution from scratch. A serious communications backbone (global network + deep telephony expertise) already underneath you. A team that's ready to shift from "the concept works" to "customers pay." The Whole Person Promise: At Keystone AI, we’re pretty proud of our corporate culture, which is rooted in our “Whole Person Promise.” We promise all employees that they can have meaningful work AND a full life, and we provide a work environment geared toward enriching your body, mind, and spirit. How do we do that? Well… 100% company-paid Medical, Vision, & Dental coverage for you and your family with low deductibles and low out-of-pocket expenses. All new hires receive four weeks of PTO. PTO Embargo. When you take time off (of any kind!) you’re embargoed from working. Bandmates and managers are not allowed to interrupt your PTO – not even with email. Additional PTO can be earned throughout the year through volunteer hours and Keystone AI challenges. “Mahalo moments” program grants additional time off for life’s most important moments like graduations, buying a first home, getting married, wedding anniversaries (every five years), and the birth of a grandchild. 90-Minute Workout Lunches and unlimited meetings with our very own nutritionist. Are you excited about the position and its responsibilities, but not sure if you’re 100% qualified? Do you feel you can work to help us crush the mission? If you answered ‘yes’ to both of these questions, we encourage you to apply! You won’t want to miss the opportunity to be a part of the BAND. Applicant Privacy Notice