[Remote] Senior Machine Learning Engineer - Voice Experience

Note: The job is a remote job and is open to candidates in USA. Cresta is on a mission to turn every customer conversation into a competitive advantage by unlocking the true potential of the contact center. They are seeking a Senior Machine Learning Engineer to help build the next generation of AI-powered voice systems, focusing on improving how AI interacts in live customer conversations.ResponsibilitiesDesign, train, evaluate, and deploy machine learning systems that power real-time voice experiences, including ASR, speech understanding, turn detection, text to speech, speech to speech, classification, entity extraction, summarization, and structured insight generationImprove the quality of voice AI systems through error analysis, data curation, metric design, benchmarking, and iterative model improvement, with a strong focus on real-world performanceBuild evaluation frameworks for complex voice and agentic systems, measuring metrics such as accuracy, robustness, latency, faithfulness, naturalness, professionalism, task completion, and costDiagnose and mitigate failure modes across the voice stack, including transcription errors, hallucinations, retrieval failures, tool misuse, prompt brittleness, context drift, and multi-step reasoning breakdownsDesign and optimize low-latency ML workflows for live conversations, balancing model quality with system responsiveness, scalability, and reliabilityPartner with platform and backend engineers to productionize real-time inference, streaming pipelines, quality monitoring, and continuous model iterationCollaborate cross-functionally with product, design, frontend, and backend teams to integrate voice intelligence seamlessly into Cresta’s platformEstablish best practices for offline evaluation, online experimentation, model validation, observability, and ongoing quality monitoring in productionMentor engineers, contribute to technical strategy, and help shape the roadmap for Cresta’s voice AI systemsSkillsBachelor's degree in Computer Science, Mathematics, Machine Learning, AI, or a related field; Master's or Ph.D. preferred5+ years of experience building, evaluating, and deploying machine learning systems in productionStrong background in one or more of the following: speech recognition, speech processing, NLP, generative AI, or conversational AIDeep experience with model evaluation, benchmarking, error analysis, and quality improvement for production ML systemsStrong expertise with modern ML frameworks and tooling such as PyTorch, TensorFlow, and Hugging FaceSolid understanding of transformer-based models, embeddings, retrieval systems, and large-scale training or inference workflowsExperience designing and deploying real-time ML systems with strong requirements around latency, scalability, and reliabilityExperience building data pipelines and tooling for experimentation, measurement, and large-scale quality analysisAbility to work across research and engineering boundaries and translate promising ideas into production-grade systemsStrong communication and technical leadership skills, with the ability to influence cross-functional decisions and raise the engineering barHands-on experience with ASR quality metrics such as WER and task-level evaluation methodologiesExperience with RAG systems, agentic workflows, multi-step reasoning systems, or LLM-as-a-judge evaluation methodsFamiliarity with streaming inference, real-time voice pipelines, or media systemsExperience working closely with infrastructure or platform teams on production ML deployment, observability, and reliabilityExperience in contact center AI, conversational intelligence, or enterprise voice productsBenefitsComprehensive medical, dental, and vision coverage with plans to fit you and your familyFlexible PTO to take the time you need, when you need itPaid parental leave for all new parents welcoming a new childRetirement savings plan to help you plan for the futureRemote work setup budget to help you create a productive home officeMonthly wellness and communication stipend to keep you connected and balancedIn-office meal program and commuter benefits provided for onsite employeesCompany OverviewCresta uses artificial intelligence to assist sales and service agents in the quality of customer service. It was founded in 2017, and is headquartered in Sunnyvale, California, USA, with a workforce of 201-500 employees. Its website is https://www.cresta.com.Company H1B SponsorshipCresta has a track record of offering H1B sponsorships, with 2 in 2026, 9 in 2025, 6 in 2024, 2 in 2023, 10 in 2022, 4 in 2021, 3 in 2020. Please note that this does not guarantee sponsorship for this specific role.