Slack was built with PHP. And here's the article from Slack engineering https://slack.engineering/taking-php-seriously-cf7a60065329 https://slack.engineering/ta

Slack was built with PHP. And here's the article from Slack engineering https://slack.engineering/taking-php-seriously-cf7a60065329 https://slack.engineering/taking-php-seriously-cf7a60065329 I guess building quicker is more important than building better, especially in hackathons or in startups where you are testing the product-market-fit. That means, one can use whatever language/tool they are most productive with. Of course, if you are lucky and if you gain momentum, then you will have the resources to re-engineer it with the right language/tool.