AI Engineer

About Keystone AI Keystone AI is the AI-native business communications platform. We unify calling, messaging, meetings, and contact center on a single platform - powered by AI that understands every conversation in real time. More than 70,000 companies around the globe, including WeWork, Asana, NASDAQ, AAA Insurance, COMPASS Realty, Uber, Randstad, and Tractor Supply, rely on Keystone AI to build stronger customer connections using real-time, AI-driven insights. We’re now leading the shift to Agentic AI: intelligent agents that don’t just analyze conversations but take action by automating workflows, resolving customer issues, and accelerating revenue in real time. Our DAART initiative (Keystone AI Agentic AI in Real Time) is redefining what a communications platform can do. Visit dialpad.com to learn more. Being a Dialer At Keystone AI, AI isn’t just a feature; it’s how our teams do their best work every day. We put powerful AI tools in every employee’s hands so they can move faster, think bigger, and achieve more. We believe every conversation matters. And we’ve built the platform that turns those conversations into insight and action, for our customers and ourselves. We look for people who are intensely curious and hold themselves to a high bar. Our ambition is significant, and achieving it requires a team that operates at the highest level. We seek individuals who embody our core traits: Scrappy, Curious, Optimistic, Persistent, and Empathetic . Your Role As an AI Engineer: Voice Designer, you’ll own the back-end implementation and linguistic optimization of the Text-to-Speech (TTS) layer for our next-generation AI voice agents. You’ll work squarely within our Speech Team—a high-impact R&D and engineering group focused on speech recognition, enhancement, and synthesis. You will bridge the gap between core speech science and product engineering, ensuring our voice agents sound human, context-aware, and trustworthy. You’ll also help create the systems that manage voice personas, tone, and conversational fillers, eventually exposing these as tweakable parameters to our customer-facing UI. This position reports to our Senior Manager, AI Speech, is based at our Vancouver hub, and operates on a hybrid schedule . What You’ll Do TTS Backend Implementation: Own the integration and optimization of multiple TTS vendor APIs while leading research and prototyping for open-source or in-house TTS architectures. Linguistic Optimization: Apply expertise in phonetics and sociolinguistics to ensure TTS input is formatted for maximum naturalness, including SSML orchestration and pronunciation handling. Conversational Turn Design: Craft context-specific utterances to optimize turn handling and build caller trust during agentic "thought" processes. Prompt & Persona Management: Design and manage LLM and TTS prompts and parameters to define and refine agent personalities across different industry verticals. UI Parameter Exposure: Architect the logic to expose voice attributes (speed, pitch, tone, style) to the product UI, allowing customers to customize their agent’s voice profile. Cross-Functional R&D: Partner with ASR and Audio AI engineers to ensure end-to-end voice quality and minimize latency in the ASR → LLM → TTS pipeline. Skills You’ll Bring Technical Foundation: Strong Python programming skills and experience with deep learning frameworks (e.g. PyTorch). Speech Expertise: 3+ years of experience in Speech Synthesis (TTS) or Voice Design, including hands-on work with frameworks like NVIDIA NeMo, ESPnet, or Coqui, and hands-on experience with major TTS APIs such as ElevenLabs, Rime, and Cartesia. Linguistic Background: Degree in Computational Linguistics, Computer Science, or AI/ML with a deep understanding of phonetics, prosody, and syntax. Prompt Engineering: Proven experience crafting and evaluating LLM prompts (system, few-shot) and managing structured prompt templates. Backend Engineering: Experience building production-grade APIs and integrating multi-vendor services in a cloud environment (GCP preferred). Evaluation Mindset: Knowledge of speech quality metrics (MOS, intelligibility, latency) and the ability to design rigorous A/B tests for voice personas. For exceptional talent based in British Columbia, Canada the target base salary range for this position is posted below. Our salary ranges are determined by role, level, and location. The range displayed on each job posting reflects the target range for new hire salaries for the position. Within the range, individual pay is determined by work location and additional factors, including job-related skills, experience, and relevant education or training. Your recruiter can share more about the specific salary range for your preferred location during the hiring process. Please note that the compensation details listed in British Columbia role postings reflect the base salary only, and do not include bonus, equity, or benefits. British Columbia, Canada Salary Range $161,500—$191,500 CAD