Principal Engineer

Twilio is a company focused on shaping the future of communications with innovative solutions for businesses and developers. They are seeking a Principal Engineer to lead the technical strategy for their Phone Numbers Platform, focusing on AI-driven development workflows and modernizing legacy systems. The role involves driving technical excellence, mentoring engineers, and translating complex regulations into developer-friendly APIs.

Responsibilities:

• 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

Requirements:

• 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
• 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 developer teams to move faster
• Agentic Systems: Experience building or integrating AI agents into internal developer platforms or automated ops workflows