Senior Machine Learning Engineer, Voice AI

Responsibilities

• Optimize inference performance for voice models (STT, TTS, speech-to-speech) — targeting best-in-class TTFB, throughput, and GPU utilization across curated model set.
• Productionize voice models on serverless and dedicated endpoints, including batching strategies, streaming inference, and memory management tailored to audio workloads.
• Build and maintain a voice model evaluation framework — measuring WER across accents, languages, and noise conditions for STT; naturalness, latency, and pronunciation accuracy for TTS.
• Enable new model architectures in serving stack as field evolves, including audio-native LLMs, codec-based models (SNAC), and speech-to-speech systems.
• Collaborate with model partners to integrate and optimize their models (Cartesia, Deepgram, Rime, and others) running on Together's infrastructure.
• Profile and debug performance across full inference stack — from GPU kernels to framework-level bottlenecks — and ship measurable improvements.
• Work with platform engineering to ensure serving layer meets latency and reliability requirements of real-time voice APIs.
• Contribute to voice model fine-tuning capabilities (STT and TTS) as customers build differentiated voice experiences.
• Lay groundwork for multiple new products.

Requirements

• 5+ years of experience in ML engineering, with focus on model serving, inference optimization, or ML infrastructure.
• Hands-on experience with LLM serving engines (vLLM, SGLang, TensorRT-LLM, or similar) — comfortable reading and modifying engine internals.
• Strong proficiency in Python and PyTorch; experience with GPU profiling and optimization (CUDA, memory management, kernel-level debugging).
• Track record of shipping ML systems to production with measurable performance improvements.
• Strong product sense — understanding developer needs for voice apps.
• Comfort working on small, early-stage team, wearing multiple hats and moving fast.

Nice-to-Haves

• Experience with speech and audio ML (ASR, TTS architectures, audio signal processing).
• Familiarity with audio codecs and tokenization schemes (SNAC, Encodec, DAC).
• Experience training or fine-tuning speech models.
• Bachelor's or Master's degree in Computer Science, Electrical Engineering, or related field, or equivalent practical experience.

Compensation

US base salary range: $200,000 - $260,000 + equity + benefits.