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3 days ago
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How a 50-engineer team built the world’s most efficient messaging platform using unconventional technology choices
When Facebook acquired WhatsApp for $19 billion in 2014, the messaging app was handling 42 billion messages daily with just 50 engineers. Behind this engineering marvel lay two unconventional technology choices that defied Silicon Valley norms: FreeBSD instead of Linux, and Erlang instead of mainstream languages like Java or Python.
This isn’t just another success story — it’s a masterclass in choosing the right tool for the job, even when that tool isn’t trendy.
By 2014, WhatsApp was processing:
- 42 billion messages per day
- 1.6 million concurrent connections per server
- 900 million active users worldwide
- 99.9% uptime across all services
Most companies would throw hundreds of servers and engineers at this problem. WhatsApp took a different approach: they chose technologies designed for exactly this kind of extreme concurrency.
