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These are the programming languages that are used by America's most valuable startups, from Airbnb to WeWork


  • Coding Dojo, a coding bootcamp, collected data from job postings on what programming languages, frameworks, and databases the top unicorn startups in the US are using.
  • These startups include names like WeWork, Juul, Airbnb, and SpaceX.
  • Some of the top languages include JavaScript, Java, and Python — although newer entrants like Kotlin and Go are also becoming popular.
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If you’ve ever wondered which languages that developers used to build multi-billion dollar startups like WeWork, Juul, Airbnb and SpaceX, look no further.

Coding Dojo, a coding bootcamp that trains developers and helps place them in programming roles, looked at full-time job postings from the job listing site Indeed and the developer tool website StackShare to see what languages the billion-dollar plus “unicorn” startups were using to build their technology.

One of the top languages Coding Dojo sees growing strong amid the unicorns is Python.

Donovan An, director of West Coast Campus Operations at Coding Dojo, says this is because Python is a general purpose language that can be used for games and web development. But what has really make it gain popularity over the past five years is the explosion of data science and machine learning in Silicon Valley.

He also sees many tech startups using Java and JavaScript, two of the most popular languages in the overall market. While Java is widely taught in computer science programs, JavaScript is ranked as the most popular programming language, but many college curriculums aren’t teaching it.

Java is the most ubiquitous language across these,” An told Business Insider. “Chances are you’ll be using Java. JavaScript which is the third language we can see, that’s called the language of the web. As the web grows, JavaScript will grow.”

Speaking of JavaScript, many JavaScript frameworks that are used to design how people interact with websites, like the Facebook-created React, are becoming popular. Frameworks provide special functionalities that help developers with building applications. 

“With your new JavaScript libraries, it makes it more interactive,” An said. “You don’t want something that’s overly static and dry and uninteractive. These frameworks like React and Angular allow you to have real time updates. All that happens real time thanks to these JavaScript libraries.”

An also says he was surprised by the popularity of newer languages like Kotlin and Go. Kotlin is the fastest growing programming language according to GitHub, and it’s most often used to develop Android apps. Go is a language that was developed by Google – an association that may have given it a leg up, An says. 

Read more: Here’s why companies like Google, Square, and Atlassian are sprinting to use Kotlin, the fastest-growing programming language according to GitHub

An said he didn’t see any surprises in what databases these startups were using. The databases MongoDB, MySQL, PostgreSQL, and Redis were especially popular.

Overall, An says companies aren’t looking for developers who know one specific language. 

“It’s important for these engineers to have a wide tool set,” An said. “What these companies are looking for in terms of is not a developer who knows Java or Golang or Kotlin. They are looking for developers who are self-sufficient and critical thinkers, not married to one language. They are looking for someone who can come in and problem solve.”

Here are the technologies that top startups are using to build their systems, according to Coding Dojo data:

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What it does: A shopping app that sells items directly from the manufacturer.

Valuation: $8 billion

Total raised: $1.5 billion

Programming languages used: PHP, Python, Golang, Ruby, Java, C, C++, Go, Perl

Frameworks used: ReactJS, Hadoop

Databases used: MySQL, MongoDB, Redis


What it does: An app that allows people to buy and sell cryptocurrency.

Valuation: $8.05 billion

Total raised: $525.31 million

Programming languages used: Go, Ruby, JavaScript, Swift, Objective-C, Kotlin, Java, C, C++, Rust

Frameworks used: ReactJS, NodeJS

Databases used: PostgreSQL


What it does: Develops therapeutic drugs for degenerative diseases.

Valuation: $12.44 billion

Total raised: $763.9 million

Programming languages used: C#, JavaScript

Frameworks used: AngularJS, Entity

Databases used: SQL

Epic Games

What it does: Develops video games like Fortnite and Unreal Engine games.

Valuation: $15 billion

Total raised: $1.58 billion

Programming languages used: Go, Java, Python, Perl, Shell

Frameworks used: n/a

Databases used: MongoDB, MySQL, PostgreSQL


What it does: Develops data analysis software for large companies, nonprofits, and government agencies. 

Valuation: $20.53 billion

Total raised: $2.75 billion

Programming languages used: Python, JavaScript, Ruby, Go, Java, C++

Frameworks used: Flask, Django

Databases used: MySQL


What it does: Develops an online payment platform that helps businesses accept electronic payments.

Valuation: $22.5 billion

Total raised: $1.03 billion

Programming languages used: Python, JavaScript, Ruby

Frameworks used: n/a

Databases used: PostgreSQL


What it does: Designs and manufactures rockets to travel to outer space and eventually to Mars.

Valuation: $33.4 billion

Total raised: $3.57 billion

Programming languages used: Python, JavaScript, Java, C++, C, PHP, Ruby

Frameworks used: n/a

Databases used: MySQL, PostgreSQL


What it does: Allows people to rent out and book property for short-term stays.

Valuation: $31 billion

Total raised: $4.4 billion

Programming languages used: Java, Ruby, Python, JavaScript, PHP

Frameworks used: ReactJS, Flask, Hadoop

Databases used: MySQL, Redis, RDS

Juul Labs

What it does: Develops nicotine vaporizers as an alternative to traditional tobacco products.

Valuation: $38 billion

Total raised: $14.15 billion

Programming languages used: Java, C, C++, Python, Go

Frameworks used: n/a

Databases used: n/a


What it does: Provides shared workspaces and office services for entrepreneurs, freelancers, startups and small businesses.

Valuation: $47 billion

Total raised: $8.39 billion

Programming languages used: JavaScript, Ruby, Python

Frameworks used: NodeJS, ReactJS, Foundation, Flask

Databases used: n/a