Principal, Machine Learning Engineer (L5)

📋 Job Overview

In this role, you will build the foundational AI/ML capabilities that power intelligent engagement experiences for Twilio customers - letting any application, human or AI agent, or channel know who a customer is, what they have done, and how best to reach them.

🏢 About Twilio

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.

🎯 The Role

This role requires a builder and curious mindset, someone who can bridge the gap across theoretical research, production-grade experimentation and enterprise quality software. You will lead rapid research cycles to solve complex problems regarding contextual intelligence and large scale ML problems ensuring every interaction feels seamless and personalized.

✅ Key Responsibilities

• Build out new functionality within a fast moving product seeing rapid adoption.
• Take a nebulous idea, design a rigorous experiment, and execute it within weeks.
• Conduct deep-dive research into state-of-the-art LLM orchestration, retrieval strategies, and data-driven personalization.
• Build ML systems that hold up at Twilio scale.
• Rapidly acquire new technical skills and knowledge in a fast-paced, high-delivery environment.
• Proactively leverage and integrate the latest AI development stacks to bypass boilerplate engineering and focus on core differentiation.

📌 Required Qualifications

• 10+ years applied ML/AI experience with a track record of owning technically ambitious systems end to end rather than contributing to someone else's design.
• Comfort operating in a 0-to-1 setting with ambiguous requirements and a strong bias for action.
• Proficiency in Python programming language.
• Experience building cloud-based services on AWS, GCP, or Azure, with high-volume data, streaming or real-time inference paths, and a range of data stores.
• Deep expertise in the design, architecture, and deployment of production-grade ML/AI systems, including LLM orchestration, embedding models, and vector stores.
• Strong fundamentals of statistical machine learning algorithms, transformer models, LLMs
• Ability to raise the technical bar of a team through mentorship, design review, and standards, without formal management authority.
• Experience in building cloud-based services using AWS, GCP, or Azure.
• Strong communication skills and highly effective collaborator who works well with teammates.

⭐ Desirable Experience

• Prior experience building autonomous agents that handle multi-turn conversations and maintain long-term context/consistency.
• Strong background in predictive modeling on user behavior, including experiment design and the causal or counterfactual methods needed when randomization is partial.
• Prior experience working in a globally distributed team.

🎁 Benefits

Working at Twilio offers many benefits, including competitive pay, generous time off, ample parental and wellness leave, healthcare, a retirement savings program, and much more. Offerings vary by location.

🛂 Visa & Eligibility

Twilio is proud to be an equal opportunity employer. We do not discriminate based upon race, religion, color, national origin, sex (including pregnancy, childbirth, reproductive health decisions, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, genetic information, political views or activity, or other applicable legally protected characteristics. We also consider qualified applicants with criminal histories, consistent with applicable federal, state and local law. Qualified applicants with arrest or conviction records will be considered for employment in accordance with the Los Angeles County Fair Chance Ordinance for Employers and the California Fair Chance Act. Additionally, Twilio participates in the E-Verify program in certain locations, as required by law.