Fluency

An AI-native language platform powered by Gemini that automates English flashcard creation with contextual sentences, dynamic visuals, and native audio.

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Inspiration

I was a solo founder, but I was never alone. Gemini became my co-founder from day one.

I was inspired by the idea that a solo founder could build a real company using Gemini as a capability multiplier. I needed a product that solved a concrete problem, but what really drove me was the idea of not getting locked into a single product. Instead of spending months building an app around one single idea, my vision was to create a low-cost technology foundation that would let me evolve the business quickly and, if the market shifted, pivot toward new opportunities without losing what I had already built. Fluency was the first business built on that vision.

How we built it

I built Fluency by clearly dividing responsibilities between the founder and Gemini. I leveraged my 20+ years of software development experience to identify the right problem, design the architecture, choose every technology, validate each technical decision, and continuously optimize the platform. Gemini accelerated execution by helping me implement features, solve engineering problems, and generate the AI-powered content that brings Fluency to life.

Fluency automates one of the most tedious parts of language learning: manually creating study material. Starting from a single word, Gemini automatically generates a sentence in context, a related image, and native pronunciation, freeing the student to spend their time actually learning instead of preparing content.

Rather than spending time building an app for a single idea, I designed a modular platform based on Clean Architecture and Hexagonal Architecture. This lets me evolve the business quickly and, if the market changes, pivot toward new products while reusing the same architecture and infrastructure.

My goal was never just to build an app, but to build a sustainable business: a low-cost platform, ready to handle high traffic, able to evolve quickly, and able to adapt to new market opportunities with the help of artificial intelligence.

Challenges we ran into

Building Fluency was about much more than developing an app. One of the biggest challenges has been turning the product into a real business.

As a solo founder, a major hurdle was setting up monetization. Integrating and getting verified with platforms like Lemon Squeezy turned out to be quite complex, requiring extra effort to get the Premium plan fully implemented.

Another challenge has been user acquisition. Without a significant marketing budget, growth depends mainly on organic channels. Beyond developing the product, I have to spend time presenting it in communities, building partnerships with local academies, and growing an audience from zero.

Building Fluency taught me that writing the software is only the beginning. Getting users, building trust, and growing a business take just as much effort as designing the architecture or writing the code.

Accomplishments that we're proud of

  • Fluency is a production platform built entirely on the Google ecosystem.
  • The app automatically generates flashcards with vocabulary, contextual sentences, images, and native pronunciation through Gemini, eliminating the manual process of creating study material.
  • Its modular architecture and optimized infrastructure keep operating costs low, support real users, and scale automatically as demand grows.

What we learned

Building Fluency changed the way I think about software development. I learned that artificial intelligence doesn't replace the founder; it amplifies my ability to execute ideas, while strategic thinking, decision-making, and accountability remain human.

I also confirmed that building a startup goes far beyond writing code. Designing an architecture built to evolve, keeping operating costs low, and acquiring users are challenges just as important as building the product itself.

What's next for Fluency

Fluency started by automating the creation of vocabulary-learning material. The next step is to turn the platform into a complete, AI-powered ecosystem for language learning.

  • The free version will remain the entry point, offering thousands of carefully curated flashcards so anyone can start studying right away. Students who want a more personalized experience will be able to access the AI Tutor through the Premium plan.
  • The platform will also add specialized collections created and validated by teachers for fields like medicine, engineering, aviation, business, and other professions. Instead of manually creating content, students will be able to access complete decks built by experts to learn the specific vocabulary of their profession.
  • The roadmap continues with new modules for grammar, reading comprehension, listening comprehension, and AI conversation practice, so students can complete their entire learning journey within Fluency.
  • Finally, Fluency will combine the best of AI and human teaching. If a student can't resolve a doubt with the AI Tutor, they'll be able to request help from a real teacher directly from the app. With a single click and using credits, they'll be connected with an available teacher to continue the lesson right where they left off.

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