As an API with a lot of complex data, our bottleneck is and always has been serializing. It has been a long journey for us to get the most performance out of this. We are proud of what we’ve accomplished. Let me share our journey trying a lot of alternatives in PHP; Including JMS Serializer, pure json decode, better serializer, Symfony serializer. And in the end: A colleague wrote php-to-go so that we could GO beyond PHP, using PHP and GoLang together, for an amazing performance boost.