Senior Fullstack Engineer, Solve

Job Description About the Role We're building a real-time voice AI product for live, natural conversations. This is a chance to work on a product where engineering quality is felt immediately by users. Every improvement to latency, reliability, and conversation flow makes the experience faster, smoother, and more human. We're looking for a Senior Full Stack Engineer who can own product features end to end, while bringing strong backend engineering fundamentals. This is a full stack role, but the center of gravity is backend: real-time systems, integrations, performance, and reliability. What You'll Work On • Build and improve the backend systems that power real-time voice conversations • Develop integrations for telephony, real-time audio, and external AI services • Ship product features across our voice platform, including user-facing web experiences where needed • Improve platform reliability, observability, and performance • Work on real-time interaction challenges like interruptions, responsiveness, turn-taking, and conversation flow • Collaborate closely with product and design to build voice experiences that feel polished and intuitive Why This Role Is Exciting • Real user impact: your work directly shapes how every conversation feels • Interesting technical problems: low-latency systems, real-time interaction, and AI-powered workflows • Broad ownership: you'll contribute across product, platform, and infrastructure • Strong opportunity: voice AI is still early, and you'll help define what great products in this space look like We'd Love to Hear From You If You • Have 3 years of experience building production software • Are a strong backend engineer first, with solid fundamentals in APIs, async systems, integrations, and system design • Have experience building and owning product features end to end • Have worked with real-time or event-driven systems such as WebSockets, WebRTC, streaming, or low-latency APIs • Care about product quality and enjoy solving user-facing problems • Are excited about voice AI, conversational products, or real-time systems Nice to Have • Experience with React and TypeScript • Experience building frontend product experiences • Experience with Python and async backend architectures • Experience with telephony, WebRTC, SIP, or audio/video systems • Experience with LLMs, speech systems, or conversational AI • Experience debugging performance or reliability issues in production Tech Stack Python, FastAPI, React, TypeScript, WebRTC, Redis, MongoDB, and modern LLM / speech infrastructure. The US annualized base salary range for this position is $145,000.00-$217,000.00. This position may also be eligible for bonus, benefits, or related incentives. While this range reflects the minimum and maximum value for new hire salaries for the position across all US locations, the offer for the successful candidate for this position will be based on job related capabilities, applicable experience, and other factors such as work location. Please note that the compensation details listed in US role postings reflect the base salary only (or OTE for commissions based roles), and do not include bonus, benefits, or related incentives. The intelligent heart of customer experience Zendesk software was built to bring a sense of calm to the chaotic world of customer service. Today we power billions of conversations with brands you know and love. Zendesk believes in offering our people a fulfilling and inclusive experience. Our hybrid way of working, enables us to purposefully come together in person, at one of our many Zendesk offices around the world, to connect, collaborate and learn whilst also giving our people the flexibility to work remotely for part of the week. As part of our commitment to fairness and transparency, we inform all applicants that artificial intelligence (AI) or automated decision systems may be used to screen or evaluate applications for this position, in accordan ... (truncated, view full listing at source)