Senior Research Engineer

Job Overview

Why AssemblyAI AssemblyAI builds the best-in-class Voice AI models powering the next generation of voice applications. Our models serve 600M+ inference calls monthly, process 1M+ hours of audio daily, and power 2 billion+ end-user experiences.

The Voice AI space is at an inflection point; we’re looking for folks truly excited to join a small team and help define the future of the industry.

Job Description

We are one of the most capital-efficient AI companies on the planet - with under 100 people generating roughly $600K ARR per employee, we sit among the top 5 most revenue-dense teams within the fastest-growing AI companies today.

That's not an accident; it's a deliberate choice to stay lean, move fast, and give every person on the team outsized ownership and impact.

With thousands of customers including Granola, Fireflies, Figure AI, and CallRail, the company has real scale - processing over 2 million hours of audio daily and handling more than 1 million API calls every day.

This is a rare growth-stage opportunity where the business is proven and the trajectory is steep, but the team is still small enough that your fingerprints are on everything.

If you've ever felt buried under layers of bureaucracy, starved of real ownership, or frustrated watching your work disappear into a slow-moving org, AssemblyAI is built differently.

The company operates as a true meritocracy, with no heavy planning or approval processes and no gatekeeping on the tools or information you need.

Key Responsibilities

• Why AssemblyAI AssemblyAI builds the best-in-class Voice AI models powering the next generation of voice applications.
• For anyone who genuinely cares about voice AI, not as a trend to chase, but as a technology to build, this is the place where the most interesting problems at the most interesting scale are being solved by a team small enough that you'll actually know everyone's name.
• At times you'll train models, run evaluations, and analyze data yourself, both to deliver impact directly and to learn what's worth building to multiply the team's work.
• Improve the data our models learn from: investigating quality issues, building the tooling to surface them, and turning what you find into measurable accuracy gains.
• Analyze the accuracy of production models, build evaluation harnesses, and work out which improvements will matter most to customers.
• Familiarity with modern inference optimization techniques: continuous batching, KV-cache management, sharding strategies, quantization.

Required Skills and Qualifications

• Our models serve 600M+ inference calls monthly, process 1M+ hours of audio daily, and power 2 billion+ end-user experiences.
• Strong experience optimizing inference systems for production, ideally with LLMs or speech models.
• Strong Python skills; C++ or Rust experience for kernel-level work is a plus.
• Bonus Domain knowledge in Speech-to-Text: ASR architectures, audio processing, streaming inference.
• There are many factors that go into salary determinations, including relevant experience, skill level, qualifications assessed during the interview process, and maintaining internal equity with peers on the team.
• The range shared below is a general expectation for the function as posted, but we are also open to considering candidates who may be more or less experienced than outlined in the .

Benefits and Perks

• Bonus Domain knowledge in Speech-to-Text: ASR architectures, audio processing, streaming inference.
• Pay Transparency: AssemblyAI strives to recruit and retain exceptional talent from diverse backgrounds while ensuring pay equity for our team.
• Our salary ranges are based on paying competitively for our size, stage, and industry, and are one part of many compensation, benefit, and other reward opportunities we provide.
• There are many factors that go into salary determinations, including relevant experience, skill level, qualifications assessed during the interview process, and maintaining internal equity with peers on the team.

Work Location and Schedule

This role is listed as Remote USA with location information shown as Remote USA. The employment type is Full Time.

About the Company

AssemblyAI is the organization connected with this listing. USA Jobs Today displays this opportunity for job discovery only, so applicants should verify company details, application instructions, and eligibility on the official employer website.