A founder used Codex to build the Norwegian tutor he wanted

Claire Vo introduces William Imoh, founder of developer marketing company Hackmamba and creator of Mural, a real-time voice app for practicing Norwegian. She asks why he built it and how he uses agents in his business.

Imoh says he tried an earlier version at a hackathon but the experience was poor. After moving from Dubai to Norway, he wanted to speak Norwegian, yet people often switched politely to English when he struggled. A 1,000-day Duolingo streak had not given him the conversation practice he wanted.

He wanted a nonjudgmental partner that would correct him and keep speaking Norwegian, like being immersed in a village where English was not an option. Vo relates this to the difficulty of getting useful reinforcement when a conversation partner switches languages.

Imoh studied chemical engineering and taught himself web development; he also spent four years as a product manager. He had not written Swift but wanted a native mobile experience and used Codex to build with Swift for iOS and Kotlin for Android.

His product experience helped him describe the intended user journey in epics and stories. He began with a long prompt requesting a beautiful Norwegian-learning app, a real-time voice model, a pulsating orb and an interface that felt like a phone call.

He specified warm autumn colors, minimalism, gradients and a design reference to Apple's visual style. The first result used dark mode, which he rejected; he asked for light, warm colors and a different treatment. He wanted unnecessary elements removed or hidden.

Vo argues that design vocabulary and concrete references help a person communicate taste to an agent. She suggests practicing by describing why two websites or brands feel different, and articulating a user journey clearly enough for either a human or AI engineer to follow.

Imoh originally built Mural for himself and hesitated to share it because supporting users would create obligations. He says other demos often had many features, while he wanted a simple conversation screen and captions to help a beginner understand.

Imoh demonstrates a conversation. The app assesses his language level, speaks Norwegian and corrects a grammatical error. When he asks it to speak English, it stays in Norwegian. Vo asks what happened and he walks her through the transcript.

Imoh says that despite his long Duolingo streak, he previously could not hold that kind of conversation. He took a short grammar course, passed a Norwegian exam and later built Mural to practice conversations in different settings.

The app tracks learned words, offers flashcards and themes, and can find material for a conversation about a selected topic. Imoh says the central experience remains speaking, receiving corrections and trying again.

Vo sees a broader skill in Imoh's approach: treating unfamiliar problems as solvable, asking questions and accepting correction. She compares an AI tutor to a patient private teacher that lets a learner make mistakes without embarrassment.

Vo asks about the real-time voice model and cost. Imoh estimates that a 30-minute session costs about $3–$5. He says the project is open source and that he initially put $1,000 in an API budget for others to use; at the time of recording about $100 remained.

Turning to his company, Imoh describes a goal to grow revenue without a comparable increase in headcount, while keeping creative work with people. As solo founder of a roughly 25-person company, he handles sales, product, hiring, customer work and administrative tasks.

After a chief-of-staff hire fell through, he experimented with assistants and created separate Codex projects for operations, growth, sales, the website and other work. A recurring weekly brief suggests what to start, stop and continue and identifies high-impact activities.

He reserves Codex for complex work such as Mural. For business functions he uses Grok Bot roles named after characters from The Lord of the Rings: Gandalf as chief of staff, with other agents covering engineering, marketing, accounts, sales, product and customer success.

Imoh says he gave the agents broad access to his business tools and enabled computer and browser use. He says they do not have write access to the bank and that he does not have access to customer data. He describes this as his own choice despite concerns about permissions.

For hiring, he built an internal system of record called Three Pipes. After a candidate conversation, he asks an agent to gather information from email, calendar and meeting notes, create a record, summarize it and rank the candidate against others he has spoken with.

Imoh says he keeps a small number of focused skills for work such as growth and content strategy; as models improved, he found some older skills unnecessary. Vo summarizes his setup as complex work in Codex projects and separate role-based business agents.

When an agent does not do what he wants, Imoh restarts it, tries a more specific sequence of steps and asks it to test and review its work. He also describes using one agent to review the work of another or switching tools when needed.

Imoh says his main anxiety is dependency: if the agents disappeared, he wonders how he would manage many sales opportunities alongside hiring and calls. Vo closes by asking where listeners can find him and learn about Hackmamba.