← Back to work
Web2026
YALLO Phone
A company softphone that works everywhere.
Why I built it
A recruitment firm lives on the phone. The team was spread across mobiles and personal numbers, with no shared history and nothing written down. I built the phone system so every call, text, and voicemail lands in one place the whole company can see.
What it does
- 01Browser softphone on the Twilio Voice SDK — Opus codec, roaming edge selection, live call-quality warnings
- 02Native iOS and Android apps sharing the same Fastify + Prisma backend
- 03Voicemail transcription via Deepgram, then summarised with Claude
- 04Two-way SMS, shared contacts, and full call history
- 05Number scoring — a heuristic that ranks how memorable a number is, so the nicest ones get offered first
- 06Admin dashboard, in-app bug reports, and push notifications
What I learned
How to debug something you cannot see. Calls to India sounded fuzzy and my first theory was carrier routing — plausible, expensive to act on, and wrong. Turning on Twilio Voice Insights and reading the actual per-leg jitter showed the carrier was the cleanest part of the call and the problem was the caller’s own uplink. Measure before you spend.