Ahmed Ben Khalifa
Full-stack software engineer
For the last four years I've been building SpeakDuo, a language-learning platform with 40,000+ learners. I work across the whole product: the React/TypeScript web app, the Python API, the React Native mobile app, and the Kubernetes cluster it all runs on.
I like owning things end to end, from the first commit to the incident response. And I like that the work matters: many of our learners are immigrants practicing a language they need for real life.
Work
I've been at SpeakDuo since 2022. A few things I've built there:
- A real-time video classroom on LiveKit (WebRTC). It has hosted 6,500+ live group classes.
- Two AI systems that listen to learners speak: a voice interview agent, and a feedback pipeline that has graded 300,000+ recordings.
- A pipeline rescue I'm proud of: parallelizing the per-recording work and batching the scoring calls cut feedback from 16 minutes to about a minute.
- Student and faculty apps for two university clients, UNSW and UCL, shipped from one monorepo.
- The iOS and Android app, where I'm the sole engineer. It's on the App Store and Play Store.
Before that I was a full-stack developer at Digital2Value, building an interactive mind-map tool that consultants used to run sessions with their clients. The interesting parts: AI-generated questions at each step, and sync that survived dropped connections.