Backend EngineerOwn, evolve, and scale the real-time infrastructure behind Stickerbox: an AI-powered voice-to-sticker printer already serving thousands.About HapikoHapiko is a Brooklyn-based company building the future of play.DescriptionFounded by Arun Gupta (former CEO of Grailed, which sold to GOAT Group in 2022) and Bob Whitney (Anthropic, NYT Games), we're on a mission to create safe, hands-on AI experiences that fuel kids' imaginations rather than replace them.Our first product, Stickerbox, is the world's first voice-to-sticker printer. A device that instantly transforms a child's spoken ideas into printable, colorable stickers. We sold out our first run shipping for the holidays, and additional batches beyond that.
It's already being called "one of the first products to make AI feel magical for kids and grounded for parents."We have a $7M funding round led by Maveron (backers of Lovevery), Serena Ventures, and Ai2 (The Allen Institute). Stickerbox is already in homes bringing imagination to life for kids nationwide!The technical challenge is real. We're running real-time streaming, processing thousands of concurrent connections from IoT devices, and orchestrating ML pipelines that return magical responses in seconds or less.
Our hybrid Python-Elixir architecture handles everything from device authentication to job queuing to image delivery, all with the reliability parents expect and the speed kids demand.We need a Backend Engineer to own and evolve this infrastructure. You'll architect and maintain the systems that connect thousands of devices, manage real-time audio pipelines, and power the experiences that make everything just work. This is a foundational role where your decisions will shape how we grow from thousands to millions of users.Real-Time InfrastructureIoT w/ audio streaming that handles tens of thousands (on our way to millions) of concurrent device connectionsDistributed job systems with Redis queues and pub/subOptimized pipelines for GenAI at high RPM with sub-second latencyMonitoring and observability to keep our infrastructure healthyAPIs & ServicesFastAPI services for device auth, user management, and webhook integrationsSecure RESTful APIs that are a joy to work withReliable integrations with external ML servicesData pipelines that feed our evaluation systemsDevOps & ReliabilityCI/CD pipelines that give the team confidence to ship fastArchitecture decisions that balance performance, cost, and maintainabilityAlerts, runbooks, and on-call practices that let the team sleep at nightYou're a great fit if you have5+ years building and shipping backend systems in PythonDeep experience with FastAPI and asyncio patternsStrong PostgreSQL skills, including schema designHands-on experience with Redis (caching, queues, pub/sub)Track record of designing reliable distributed systemsA DevOps mindset, comfortable deploying, monitoring, and scalingExperience with GenAI/LLM pipelines deployed in productionClear communication skills; can translate technical tradeoffs for the teamBonus if you haveWorked with Elixir/Phoenix and enjoy managing concurrencyBuilt software for IoT or custom hardware devicesManaged real-time systems and streaming dataExperience with streaming protocols and media formatsTuned ML pipelines with prompt engineering and evalsOur stackBackend: Python, FastAPI, Elixir/PhoenixData: PostgreSQL, RedisInfra: DockerLocation: NYC only, On-site (flexible on WFH but we like to be in office the majority of the week) in our Brooklyn based office, close to most major train lines.Salary: $150,000 - $250,000 per year