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Comment by mk89 | Hacker News Reader

No but whatsapp was built by 2 guys that had previously worked at Yahoo, and they picked a very strong tech for the backend: erlang.

So while they probably didn't bother scaling the service to millions in the first version, they 1) knew what it would take, 2) chose already from the ground up a good technology to have a smoother transition to your "X millions users". The step "X millions to XYZ millions and then billions" required other things too.

At least they didn't have to write a php-to-C++ compiler for Php like Facebook had, given the initial design choice of Mark Zuckeberg, which shows exactly what it means to begin something already with the right tool and ideas in mind.

But this takes skills.

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> No but whatsapp was built by 2 guys that had previously worked at Yahoo, and they picked a very strong tech for the backend: erlang.

https://news.ycombinator.com/item?id=44911553

Started as PHP, not as Erlang.

> 1) knew what it would take, 2) chose already from the ground up a good technology to have a smoother transition to your "X millions users".

No, as above, that was a pivot. They did not start from the ground up with Erlang or ejabberd, they adopted that later.

Thanks, somehow I remembered wrong.

They took already existing protocol (XMPP) and already existing implementation in Erlang (ejabberd)—there weren't many alternatives at the time really.

Did they succeed because of Erlang or in spite of Erlang? We can't draw any reliable conclusions from a single data point. Maybe a different platform would have worked even better?

Yeah - the technology used is a seperate concern to their abilities as users (developers) of that technology and the effectiveness at handling the scale.

I, for example, have always said that I am more than capable of writing code in C that is several orders of magnitude SLOWER than what I could write in.. say Python.

My skillset would never be used as an example of the value of C for whatever

Erlang is uniquely suited to chat systems out of the box in a way that most other ecosystems aren't. Lightweight green threads via the BEAM vm, process scheduler so concurrent out of the box, immutable data structures, message passing as communication between processes.

There's nothing unique about Erlang. I have nothing against it but other companies have built messaging systems using other platforms that work as well or better than WhatsApp.

Examples please.

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