Engineering - We're Hiring - New
AI/ML Engineer - Voice Engine
Remote - Full
At Callin.io, we're building the voice AI infrastructure that powers the next generation of human-machine conversations. Our platform handles millions of conversation minutes, enabling businesses to deploy intelligent voice agents that feel genuinely natural. We're a small, senior team moving fast on hard problems — and we're looking for engineers who thrive in that environment.
As an AI/ML Engineer, you'll work directly on Neuron 1.0 — callin.io's proprietary voice engine. This is the brain behind every conversation our platform powers: the system that listens, understands, thinks, and responds in real time. You'll own meaningful parts of the NLU pipeline, improve speech recognition accuracy, refine response generation quality, and push the boundaries of what's possible in terms of latency and naturalness.
This is not a research role disconnected from reality. You'll be shipping models and optimizations that go into production and affect real conversations at scale. You'll work alongside backend engineers and product stakeholders, with a high degree of autonomy and direct impact on the core product.
Develop and optimize components of the Neuron 1.0 voice engine across the full conversation stack
Improve natural language understanding pipelines for intent recognition, entity extraction, and contextual awareness
Fine-tune and integrate speech-to-text and text-to-speech models for accuracy, naturalness, and speed
Optimize response generation using LLMs — prompt engineering, fine-tuning, retrieval augmentation, and beyond
Drive latency reduction across the pipeline so conversations feel instantaneous and fluid
Evaluate model performance rigorously and build the tooling needed to iterate fast
3+ years of hands-on experience in machine learning or AI engineering, with production deployments under your belt
Strong Python skills and deep familiarity with PyTorch or TensorFlow — you're comfortable going from research paper to working implementation
Practical experience working with large language models — fine-tuning, inference optimization, or building LLM-integrated systems
Solid understanding of speech-to-text and text-to-speech pipelines, including model selection, evaluation, and integration
A rigorous, experimental mindset — you form hypotheses, design clean tests, and let data drive decisions
Ability to communicate clearly and collaborate across engineering and product in an async remote environment
Experience with real-time inference systems and latency-sensitive ML pipelines
Background in voice conversation design — understanding of prosody, pacing, and what makes a voice interaction feel human
Familiarity with streaming audio architectures and how they interact with ML systems
Prior work on conversational AI, voice assistants, or dialogue systems
Work on the core product. Neuron 1.0 isn't a side project — it's the engine everything else runs on. Your improvements ship directly into millions of conversations.
Full ownership. We're a small team. There's no committee to approve your experiments or a backlog of tickets blocking your ideas. If you see a better approach, you test it and ship it.
Async-first, fully remote. Work from wherever you do your best thinking. We care about outcomes, not office hours.
Voice AI is still wide open. The intersection of LLMs, real-time speech, and conversational design is one of the most technically interesting spaces in AI right now. You'll be shaping it from the inside.
Competitive compensation. Salary benchmarked to senior AI/ML engineering roles at top-tier tech companies, regardless of your location.
Apply
Our hiring process is designed to be respectful of your time while giving us confidence you're the right fit.
01
Application Review: 15-30 minutes Submit your application with resume/portfolio. We review every application personally and respond within 5 business days.
02
Initial Screen: 30 minutes Quick video call with our recruiting team to discuss your background, the role, and answer initial questions.
03
Technical/Skills Assessment: Varies by role For engineering roles: coding challenge or take-home project. For other roles: case study, portfolio review, or role-specific exercise.
04
Team Interviews: 2-3 hours total Meet potential teammates and leadership. We typically schedule 2-3 conversations covering technical skills, culture fit, and role-specific deep dives.
05
Final Decision: 2-3 days We move quickly. You'll hear our decision within 2-3 days after final interviews. If it's a yes, we'll extend an offer immediately.
Total Timeline: 2-3 weeks from application to offer