Voice AI Engineer

Intro

For this position we are only looking for candidates located in Greece, Germany or Austria.

Nairon GmbH is a Swiss startup building AI voice agents that answer and make phone calls for businesses. Our platform runs real-time conversations over the phone and on the web, connected to our customers' telephony and business tools. We value clear communication, thoughtful engineering, and a collaborative approach to problem-solving. Join us as we continue to develop tools that make a difference.

Tasks

As a Voice AI Engineer at Nairon GmbH, you will make our agents sound fast, natural and reliable in live calls. Your responsibilities will include:

• Improving turn-taking: when the agent speaks, waits, yields or gets interrupted, including voice activity and end-of-turn detection.
• Cutting end-to-end latency across speech recognition, language models and speech synthesis, and making provider failover seamless.
• Optimising how we use LLMs in conversation: prompting, tool calls, streaming and speculative or parallel requests.
• Serving our own speech models (STT and TTS) on GPUs, measuring throughput and time to first audio.
• Fine-tuning speech and language models for our customers' languages and voices.
• Building evaluation: test calls, benchmarks and quality metrics that tell us when a change really helps.

Requirements

Experience:

A senior or strong mid-level engineer with production experience in real-time audio, conversational AI or ML model serving.

Technical Skills:

Required:

• Strong Python, including asyncio and streaming pipelines.
• Hands-on work with speech (STT, TTS, VAD) and LLM APIs in latency-sensitive systems.
• Model serving on GPUs, for example with vLLM or similar, and the basics of batching and memory limits.

Nice to have:

• LiveKit Agents, pipecat or WebRTC.
• Fine-tuning (LoRA or full) of speech or language models.
• Audio signal processing such as echo cancellation or noise suppression.
• German, or experience with German-language speech data.

Communication:

• English proficiency is essential, both written and spoken, as it is the working language for all positions.

Soft Skills:

• You measure before and after, and trust numbers over impressions.
• Ownership of a problem from the first bad call to the fix in production.

Benefits

• Flexible Work Setup: Work fully remotely or from a co-working space — whichever suits you best.
• Equipment Provided: Company laptop and phone provided for all employees.
• Collaborative Environment: Join a small, agile team where your contributions have a direct impact.
• Growth Opportunities: Work across the whole voice stack, from model serving to the conversation the caller hears.

Closing

If you want to make AI conversations feel human on a real phone line, we'd love to hear from you.