Principal Engineer

Who we are At Twilio, we're shaping the future of communications, all from the comfort of our homes. We deliver innovative solutions to hundreds of thousands of businesses and empower millions of developers worldwide to craft personalized customer experiences. Our dedication to remote-first work, and strong culture of connection and global inclusion means that no matter your location, you're part of a vibrant team with diverse experiences making a global impact each day. As we continue to revolutionize how the world interacts, we're acquiring new skills and experiences that make work feel truly rewarding. Your career at Twilio is in your hands. We use Artificial Intelligence (AI) to help make our hiring process efficient. That said, every hiring decision is made by real Twilions! . See yourself at Twilio Join the team as Twilio's next Principal Engineer. About the job The Phone Numbers Platform is the heartbeat of Twilio. In 2026, "getting a phone number" is no longer a simple API call; it is a sophisticated orchestration of global inventory, real-time identity verification (KYC), and automated regulatory compliance. As a Principal Engineer (P5), you will own the technical strategy for a platform that processes millions of requests. You will be expected to pioneer AI-driven development workflows using LLMs and agentic agents to accelerate code generation, automate architectural reviews, and synthesize complex global telecommunications regulations into executable logic. Your mission is to collapse the distance between a great idea and a production ready feature. Responsibilities In this role, you'll: • DRAW THE OWL: Lead the architecture and long-term technical roadmap for the Phone Numbers Platform, transitioning legacy systems into a modern, distributed microservices architecture that supports global scale. • ACCELERATE WITH AI: Lead by example in using AI coding assistants (GitHub Copilot, Anthropic Claude, or internal LLMs) to automate boilerplate, generate exhaustive test suites, and perform rapid prototyping. You will be measured on your ability to amplify your own output and the team's velocity through AI augmentation. • BE AN OWNER: Drive technical excellence across multiple teams, making critical architectural decisions that balance rapid feature innovation with world-class reliability and security. • WEAR THE CUSTOMER'S SHOES: Partner with Product Managers to translate complex global telecommunications regulations and customer needs into elegant, developer-first APIs and application workflows. • EMPOWER OTHERS: Mentor and uplift senior and staff engineers. Foster a culture of technical curiosity, ownership, and continuous learning. Teach the team how to move from "writing code" to "reviewing and orchestrating AI-generated logic" without sacrificing security or quality. • RUTHLESSLY PRIORITIZE: Identify and mitigate technical risks early, ranging from scalability bottlenecks to security vulnerabilities and lead the team through complex production incidents with a focus on long-term remediation. • WRITE IT DOWN: Communicate complex technical strategies to both executive leadership and engineering teams through high-quality design documents, RFCs, and presentations. Qualifications Twilio values diverse experiences from all kinds of industries, and we encourage everyone who meets the required qualifications to apply. If your career is just starting or hasn't followed a traditional path, don't let that stop you from considering Twilio. We are always looking for people who will bring something new to the table! *Required: • 12+ years of experience designing and developing highly available, high scale, secure, mission-critical cloud native enterprise distributed systems. • Expert Proficiency in Java or Go, with deep knowledge of AWS ecosystems (Lambda, EKS, DynamoDB, Kafka). • Architectural Mastery: Deep experience with cloud-native infrastructure (AWS preferred), microservices patterns, and designing "five-nines" (99.999%) resilient systems. • AI-Native Workflow: Demonstrated experience using AI tools to significantly accelerate software delivery. You should be comfortable discussing how you use LLMs for architectural brainstorming, debugging, and code synthesis. • API Excellence: A track record of building and maintaining high-volume public-facing APIs that focus on exceptional developer experience. • Data Savvy: Experience with high-throughput data processing and storage solutions (SQL/NoSQL, Redis, Kafka, or Spark). • Infrastructure as Code: Proficiency with Kubernetes, Terraform, and modern CI/CD paradigms. • Leadership: Proven ability to influence technical strategy across multiple teams and organizational boundaries without direct authority. Desired: • Telecom Domain Expertise: Experience with telephony protocols, local number porting (LNP), or global regulatory compliance frameworks. • Platform Thinking: Experience building "internal platforms" that enable other d