JavaScript is to make more dynamic and interactive website or app ultimately drawing users when your startup is still in its early stages.
Ruby
Ruby is old but still best. Programmer use Ruby for developing REST API. Many big companies still using this language.
Kotlin
Kotlin has an unbelievable closeness with Java. It is a straightforward language which is the reason it is developing at a quick speed.
Python
Python is one of the top language in startup. Fast development, easy, large community. And mostly it has large collection of libraries which save time.
Go
Go is simple language so new startups can try without any complexities. It's statically typed so it's fast and my startups looking for it.
Swift
Swift in startups makes speedy development, safer, simple, and easy to error handling for developers.
Perl
Perl is another best language for startups and it's general purpose language. Perl grants a variety of modules under its Comprehensive Perl Archive Network.
PHP
PHP is old but 80% of website on internet using PHP. It's very easy to learn so anyone learn and build startup.
Scala
Scala is also best choice to build scalable apps. Startuppers can likewise go with Scala as a substitute for Python to deal with large project.
Java
Java is everywhere, it's great language for startup. Mainly, Java is one of the finest names for building web apps and enterprise softwares.