At Ello, our mission is to maximize the potential of all children. Our first product (Read with Ello) is an AI reading teacher that listens to a child read from real books. It uses evidence-based reading instruction to help them when they get stuck and behavioral psychology to motivate them to keep going. We’re now building on the success of Read with Ello and putting together the pieces of the world’s first complete AI teacher for children.

We’re a highly technical team building delightful learner-centered experiences which leverage the massive recent advances in AI. Our products put children on a path of lifelong learning, creating the foundation for their future and ours. Together, we believe we can close literacy and educational gaps around the world. We are backed by world-class investors, just closed a Series A, and we’re ready to bring on new talent to help achieve our vision.

Our team has deep expertise in artificial intelligence, K-12 education, and child development across institutions such as Stanford, Berkeley, Google, Apple, and more. We were part of Y Combinator’s W20 batch and have recently closed a funding round; previously announced investors include leading US and European VCs including Project A Ventures, Reach Capital, Khosla Ventures, Homebrew, WndrCo, Human Capital and K9 Ventures.

We’re a small, collaborative team that takes each other’s voices very seriously. Because our mission is to support all children, it is critical that our team is representative of the wider community; we place significant emphasis on ensuring diversity in our team and inclusion in our culture. We want to create an environment in which we can all be our best selves, use our strengths to take Ello forward, and develop our own skills. We want to have fun while working hard to do impactful things that we’re proud of – we believe it’s possible to do both.

Our mission at Ello is simple and urgent: Maximize the potential of every child, everywhere.

We’re building the world’s first AI teacher to close that gap: one that listens, speaks, adapts, and inspires, just like the best human educators.

Our first product, Read with Ello, is already helping tens of thousands of kids each week learn to read. It listens as they read aloud, offers support when they stumble, and generates magical, personalized stories using generative AI. It works—and kids love it.

Now, we’re scaling that success into something even bigger: a complete AI teacher for all children. We’re building a real-time learning platform—one that combines language, speech, and memory to power personalized, interactive education for kids worldwide. We’re moving fast: we ship weekly, test directly with kids and families, and push the boundaries of what AI can do in education.

With the resources of the world's top investors and the heart of a public benefit corporation, we’re here to revolutionize how children learn globally. Featured on TIME’s Best Inventions and Fortune’s Change the World, Ello is a small, mission-driven team taking on one of the most important challenges of our time: to democratize education.

Who you’ll be joining

Ello is a rapidly growing, series A startup focused on revolutionizing the way children learn and interact with technology. You will work directly with Ello’s Co-founder & CTO, Catalin Voss, on a small team (<10) of engineers, learning designers, and PMs to develop new products. You’ll be surrounded by a team of A+ engineers and you’ll work with some of the foremost experts in ML to productionize models and build new product experiences. We work in-person out of our San Francisco office and we’re big believers in face-to-face collaboration.

About the role

We’re looking for a strong Sr. Product Engineer to independently own the build-out of learning activities as part of Ello’s next-generation AI tutoring apps. You will bridge the gap between product development and engineering to own features from conception to playtest, at times acting as your own product manager, and at times collaborating closely with our product team. You’ll be part of a small team that is responsible for bringing Ello’s tutoring AI to life through agent control, character development, and game interactions. You pay attention to the details and thrive building products that delight users.

You can work full-stack and across multiple programming languages, build chains, etc. Learning yet another language doesn’t feel like a daunting task at this point. You have experience with or a demonstrated curiosity for GenAI pipelines. On the backend, you’re able to write performant Python code and deal with complex I/O pipelines. On the frontend, you’re able to take an existing component library and build a rough UI from scratch (Flutter & React) without a designer or implement pixel-perfect layouts in collaboration with a designer.

We welcome candidates from all backgrounds – mobile engineering, machine learning, or design & product – but we prioritize strong technical foundations and demonstrated execution speed in shipping. As an ideal candidate, you’ll have built and shipped software products end-to-end in the past, for example through an initiative you championed at a prior job, through an impressive side project, or as the founder of your own company. We’d love to hear about those in the interview process!

Responsibilities

• Own and build features end-to-end, from concept to delivery
• Build agent-based AI pipelines, interfacing with ML engineers working on core models (e.g. our child speech recognition pipeline)
• Serve as a bridge between product design and engineering, moving fluidly between UX/UI and technical problem-solving
• Develop and integrate front-end components for mobile and web platforms, leveraging existing design systems and brand guidelines
• Do whatever it takes to go from product conception to playtest

Required Experience

• Engineering:

  • Excellent production-grade engineering & debugging skills across backend, ML, and mobile frontend
  • Experience with at least one of Flutter, native Android development in Java/Kotlin, or iOS development in Swift/ObjC
  • Experience with ML tooling and GenAI tools (you don’t need to be a linear algebra beast designing your own models, but you should understand how multimodal models work and communicate with ML engineers in their language)
  • Some experience with GenAI models & pipelines, including human eval infrastructure
  • Familiarity with Git flow, etc.
  • Basic data science skills (enough to analyze your own product insights)
  • Familiarity with basic infrastructure setup, continuous integration, and production release workflows

• Design & Product:

  • Very high level of attention to detail. For example, you see how small changes in a character’s facial expression or the shading of a background affect the emotional impact of the end product
  • Demonstrated bias to action in product building: creating something from nothing and turning chaos into order
  • Demonstrated ability to work within existing design systems and brand standards to build new front-end components
  • Cross-functional skills; you likely either picked up engineering from a product/design domain or product skills from a computer science background
  • Familiarity with project management tools and collaborative development tools

Nice to have experience

• Experience with game development
• Experience as a product manager or in a role with significant ownership over features or components
• Deep understanding of mobile app architecture, design patterns, and performance optimization techniques
• Experience with designing products for children

We look for candidates who

• Have something to teach us
• Want to do work they are proud of to ship products they are proud of
• Have an urge to make a real impact on child development at scale
• Take initiative and full ownership of their work
• Prefer open and direct communication grounded in empathy to beating around the bush
• Exemplify integrity in their actions, decisions, and communication
• Want to build meaningful relationships at work

Here are some reasons to be a part of our team

• Dive deep into the rapidly evolving world of AI and interactive learning.
• Experience the joy of turning your designs and code into engaging and educational experiences for children worldwide
• Be part of an A+ team and an engineering culture of excellence

About Ello

Ello is a public benefit corporation on a mission to maximize the potential of all children. We’re currently around 45 people, headquartered in San Francisco, with offices in São Paulo, Brazil; Nairobi, Kenya; and New York.

Our team has deep expertise in artificial intelligence, K-12 education, and child development across institutions such as Stanford, Berkeley, Google, Apple, and more. We were part of Y Combinator’s W20 batch and are funded by world-class investors including Goodwater Capital, Homebrew, Reed Hastings, Common Sense Growth, Ravensburger, Project A Ventures, Reach Capital, Khosla Ventures, WndrCo, Visible Ventures, and K9 Ventures.

We’re a small, collaborative team that takes each other’s voices very seriously. Because our mission is to support all children, it is critical that our team is representative of the communities we work in; we place significant emphasis on ensuring diversity in our team and inclusion in our culture.

We feel enormously privileged to be one of the few companies that has the opportunity to take a shot at truly revolutionizing education with AI at this inflection point in technology. We don’t take it for granted, so we work quite hard to turn that vision into reality with urgency. We want to create an environment in which we can all be our best selves, use our strengths to take Ello forward, and develop our own skills. We want to have fun while working hard to do impactful things that we’re proud of – and we believe it’s possible to do both.

Our stack spans across various technologies, from custom-built in-house real-time ML models, to our consumer-facing mobile app, to internal infrastructure and tools. An overview of the different parts of our tech stack:

AI/Machine Learning

• Custom built child speech recognition model for real-time inference, written in C++
• Python libraries for ML prototyping and training (Pytorch, TensorFlow, sklearn, etc.)
• Infrastructure running continuous model training & fine tuning on GCP/AWS
• Applied state-of-the-art AI foundation models for adaptive applications & generative content

Mobile App

• Ello mobile app built using Unity (running on iOS/Android/Kindle).
• Custom bridging interface connecting Unity app front-end with on-device child speech model & service (ObjC/Swift on iOS and Java/Kotlin on Android)

Web Frontend

• Customer-facing and internal web portals written in React

Backend

• NestJS backend using MongoDB
• GraphQL API served over Apollo