Principal, Machine Learning Engineer (L5)

Twilio’s Customer Memory Team is building foundational AI and ML capabilities to enable intelligent engagement by understanding customers, their history, and the best way to reach them. As a Principal Machine Learning Engineer, you will help translate research into production-grade experimentation, tackling contextual intelligence and large-scale ML challenges in a fast-moving, rapidly adopted product.

What you’ll work on

You will develop and ship new functionality for a system that can identify customers, understand their context, and improve how outreach is delivered. The role blends deep technical research with the ability to move from an early, unclear idea to a rigorous experiment that can be executed in weeks.

• Build out new product functionality with rapid adoption.
• Design experiments from nebulous ideas and execute them quickly.
• Perform deep-dive research into state-of-the-art LLM orchestration, retrieval strategies, and data-driven personalization.
• Develop machine learning systems that can operate reliably at Twilio scale.
• Continuously acquire new technical skills in a fast-paced, high-delivery environment.
• Proactively integrate modern AI development stacks to reduce boilerplate and focus on core differentiation.

Required experience

• 10+ years of applied ML/AI experience with a track record of owning technically ambitious systems end to end.
• Comfort operating in a 0-to-1 setting with ambiguous requirements and a bias for action.
• Proficiency in Python.
• Experience building cloud-based services on AWS, GCP, or Azure, including high-volume data, streaming or real-time inference paths, and multiple data stores.
• Deep expertise in production-grade ML/AI system design, architecture, and deployment, including LLM orchestration, embedding models, and vector stores.
• Strong fundamentals of statistical machine learning algorithms, transformer models, and LLMs.
• Ability to raise the technical bar through mentorship, design review, and standards without formal management authority.
• Prior experience building cloud-based services using AWS, GCP, or Azure.
• Strong communication skills and the ability to collaborate effectively.
• Experience building autonomous agents that handle multi-turn conversations and maintain long-term context or consistency.
• Background in predictive modeling on user behavior, including experiment design and causal or counterfactual methods when randomization is partial.
• Prior experience working in a globally distributed team.

Tools you’ll use

• Python
• AWS, GCP, Azure
• LLM orchestration
• Embedding models
• Vector stores
• Transformer models

Location and travel

This is a remote role based in India (Karnataka, Tamil Nadu, Telangana State, Maharashtra, and New Delhi). Occasional travel may be required for project or team in-person meetings.

Benefits

• Competitive pay
• Generous time off
• Ample parental and wellness leave
• Healthcare
• A retirement savings program

How Twilio works

• We use Artificial Intelligence (AI) to help make our hiring process efficient.
• Every hiring decision is made by real Twilions.
• Remote-first, with ad-hoc requests to report in person for team gatherings, functional off-sites, or customer meetings.

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