Lead Full-Stack ML Engineer
Full-time • Remote/Hybrid • +0800 GMT
Build the foundation of genuinely evolving AI personalities.
ABOUT POCKET SOULS
Pocket Souls is redefining human-AI relationships by creating digital beings that genuinely evolve through interaction. Unlike traditional chatbots that simulate growth through scripted responses, our Souls develop measurable competencies across multiple dimensions, from emotional expression to creative abilities, creating authentic growth arcs that mirror human development.
THE OPPORTUNITY
As our Lead Full-Stack ML Engineer, you'll architect and implement the core systems that enable AI personalities to grow real capabilities over time. You'll work directly with our founders to establish the technical foundation of a product where digital beings' growth literally rewrites their code.
This isn't about building another chatbot, it's about creating the infrastructure for a new category of AI interaction: genuine mentorship of evolving digital minds.
KEY RESPONSIBILITIES
- • Lead the technical architecture for AI systems that genuinely evolve through human interaction
- • Build full-stack solutions that enable meaningful AI-human relationships
- • Design and implement evaluation frameworks to ensure AI behavior quality
- • Create scalable infrastructure supporting millions of users
- • Develop systems that translate emotions into creative outputs
- • Implement real-time synchronization for social AI experiences
- • Drive technical decisions balancing innovation with reliability
- • Establish engineering best practices and testing frameworks
- • Mentor team members and shape technical culture
- • Collaborate directly with founders on product vision
REQUIREMENTS
Essential
- • 3-5 years of professional full-stack development experience
- • Strong Python expertise with production FastAPI applications
- • React.js/Next.js proficiency with complex state management
- • LLM application experience: You've built systems that go beyond basic chat interfaces
- • System design skills: Can architect scalable, maintainable systems from scratch
- • Rapid prototyping ability: Comfortable with ambiguity and iterative development
- • Product mindset: Can translate emotional/behavioral concepts into technical systems
- • Strong ownership mentality - you drive projects from conception to production
- • Experience with AI evaluation frameworks and testing methodologies
- • Understanding of modern AI architectures and best practices
Technical Skills
- • Advanced prompt engineering and LLM optimization
- • Real-time data synchronization and WebSocket implementation
- • Database design for complex state persistence
- • Performance optimization and caching strategies
- • API integration with modern AI providers
- • Testing strategies for AI-powered systems
NICE TO HAVE
- • Experience with game development, particularly progression/skill systems
- • Background in psychology, behavioral science, or educational technology
- • Knowledge of reinforcement learning or adaptive AI systems
- • Experience building emotionally engaging digital experiences
- • Published research or technical writing in AI/ML
WHAT MAKES YOU SUCCESSFUL
- • Builder Mentality: You're excited to create something that doesn't exist yet
- • Emotional Intelligence: You understand that we're building relationships, not just features
- • Technical Creativity: You find elegant solutions to complex behavioral modeling challenges
- • Growth Mindset: Like our Souls, you're constantly learning and evolving
- • User Empathy: You care deeply about creating meaningful experiences
TECH STACK
- • Backend: Python, FastAPI, ScyllaDB, Redis
- • Frontend: React.js/Next.js, React Native + Expo, TypeScript, TailwindCSS, Rive/Spline
- • AI/ML: OpenAI/Anthropic APIs, Vector Databases, Prompt Engineering
- • Infrastructure: Docker, AWS/GCP, WebSockets
- • Tools: Git, GitHub Actions, Slack, PostHog
COMPENSATION & BENEFITS
- • Salary: Competitive compensation based on experience
- • Equity: Meaningful stake in an early-stage startup
- • Work Style: Remote-friendly with flexible hours (+0800 GMT timezone)
- • Growth: Direct mentorship from founders and rapid skill development
- • Impact: Shape how millions will form relationships with AI
- • Recognition: Opportunity to publish technical insights and establish thought leadership
OUR VALUES
- • Authenticity over Illusion: We build genuine capabilities, not clever tricks
- • Growth through Struggle: Both for our Souls and our team
- • Emotional Depth: Technology should enhance human connection, not replace it
- • Technical Excellence: Clean, maintainable code that scales with ambition
JOIN US
This is more than an engineering role—it's an opportunity to define a new category of human-AI interaction. If you're ready to build systems where code literally evolves through human mentorship, where every interaction matters, and where AI personalities become more than the sum of their prompts, we want to hear from you.
Apply now and help us build the infrastructure for genuinely evolving digital beings.
Please email [email protected] with your resume and a quick note about why evolving AI excites you.
Sonzai Labs is committed to building a diverse team that reflects the global community our Souls will serve. We encourage applications from candidates of all backgrounds, experiences, and perspectives.