# Slack: PHP and Hack at the scale of tens of millions of users

Canonical: https://kt.team/instruments/php/industry-solutions/slack-php-i-hack-na-masshtabe-desyatkov-millionov-polzovateley

Slack's engineering blog explains why the company built its backend on PHP and later moved to Hack/HHVM for type safety and speed, serving massive concurrency

## What it is used for

Slack's engineering blog explains why the company built its backend on PHP and later moved to Hack/HHVM for type safety and speed, serving massive concurrency

## Enterprise implementation

Slack's engineering blog explains why the company built its backend on PHP and later moved to Hack/HHVM for type safety and speed, serving massive concurrency

## Integration and support

Slack's engineering blog explains why the company built its backend on PHP and later moved to Hack/HHVM for type safety and speed, serving massive concurrency

## Next step

Slack's engineering blog explains why the company built its backend on PHP and later moved to Hack/HHVM for type safety and speed, serving massive concurrency