LinkedIn is one of the most popular professional networking platforms, with over 850 million members worldwide as of 2022. With members spanning across 200 countries, LinkedIn aims to connect professionals across different industries and allow them to build their professional networks. As a crucial tool for networking and job seeking today, many professionals have the LinkedIn mobile app installed on their smartphones.
This allows them to access their LinkedIn network and keep updated no matter where they are. With the LinkedIn app’s wide usage and importance in business today, many may wonder – what coding language is the LinkedIn app written in? Let’s take a look at the details.
The LinkedIn Mobile App
The LinkedIn mobile app allows users to access core LinkedIn features on-the-go. This includes viewing profiles, connecting with other members, searching for jobs, messaging contacts, getting notified of updates, sharing articles and media, and more. The app is available across mobile platforms like iOS and Android.
The iOS app first launched in March 2009, while the Android app launched in August 2010. Today, the LinkedIn app sees millions of active users every month and is one of the top social media apps installed on smartphones globally. It is a critical mobile tool for LinkedIn’s members worldwide.
Platform Architecture
LinkedIn uses a microservices architecture to build its mobile apps and other software systems. With microservices, large applications are broken down into small modular components called services. Each service has its own logic and performs a specific function.
Microservices allow for easier development, testing and updating of complex applications. It also enables individual services to scale as needed based on usage demand. This architecture provides LinkedIn the flexibility and speed needed to quickly innovate and roll out new features to its mobile apps.
Mobile App Development
For its mobile app development, LinkedIn uses a cross-platform mobile development framework called React Native. React Native allows mobile apps to be built using React, a popular JavaScript library for building user interfaces. The same React Native code can then be used to generate native iOS and Android app experiences.
Some key advantages of using React Native for LinkedIn include:
- Write Once, Use Anywhere – React Native code can be reused across iOS and Android instead of having to rewrite it natively for each platform.
- Faster Development – The reusable code and ability to live reload changes speeds up the development process.
- Performance – React Native provides nearly native performance experience and smooth UI animations due to its direct access to native APIs.
- Access to Native Features – React Native still allows access to native device capabilities like camera, location, notifications etc.
- Modular & Scalable – Aligns well with LinkedIn’s microservices approach with its modular structure.
- Large Ecosystem – Large open source community provides readymade components speeding up development.
Additionally, LinkedIn has shared that they leverage TypeScript for writing React Native code. TypeScript is a typed superset of JavaScript that provides benefits like early error checking, inline documentation and auto-completion.
Key Languages Used
Based on LinkedIn’s tech stack for its mobile apps, here are some of the key programming languages used:
JavaScript
JavaScript is the core language used for building the UI and application logic in React Native. It provides the flexibility and dynamic behavior needed for an interactive mobile app experience.
TypeScript
As mentioned earlier, LinkedIn uses TypeScript to write the React Native code for its apps. TypeScript extends JavaScript by adding static type checking and class-based object-oriented programming. This improves code quality and maintainability.
Objective-C/Swift
For iOS specific components, LinkedIn leverages Objective-C and Swift, the native languages for iOS development. This allows tight integration with iOS specific APIs and features not available in React Native.
Java/Kotlin
Similarly for Android, LinkedIn uses Java and Kotlin to handle Android platform-specific requirements. Kotlin is now Google’s preferred language for Android development, providing concise and efficient code.
HTML/CSS
LinkedIn uses HTML and CSS for rendering UI screens and components. React Native converts the HTML-like syntax to native UI elements. CSS is used for styling and layouts.
Server-side Development
For LinkedIn’s extensive server-side logic and services, core languages like Java, Python, Scala, and Ruby are utilized. This server-side code powers LinkedIn’s APIs that deliver data and capabilities to its mobile and web apps.
Here is a breakdown of some of the server-side languages used by LinkedIn:
Language | Use Cases |
---|---|
Java | General purpose backend development, core LinkedIn services |
Python | Data science, machine learning models |
Scala | High performance services, distributed computing |
Ruby | Web development, automation scripts |
Testing Frameworks
LinkedIn relies heavily on testing to ensure high quality and reliability across its apps. For React Native, LinkedIn uses frameworks like:
- Jest – For unit testing React Native code and components.
- Appium – For automating UI testing across Android and iOS.
- Espresso – For Android UI testing.
These frameworks allow LinkedIn to thoroughly test its React Native codebase and catch issues early before release.
Continuous Integration/Deployment
LinkedIn also leverages continuous integration and continuous deployment (CI/CD) workflows to ship updates faster and more reliably. Some of the tools used include:
- Buildkite – LinkedIn’s CI/CD platform to test and release updates.
- Fastlane – Automating release builds and publishing to app stores.
- Bitrise – iOS CI/CD with parallel testing on thousands of devices.
These tools enable LinkedIn to continuously build, test, and ship changes on both iOS and Android efficiently.
Conclusion
The LinkedIn mobile app is powered by a technology stack that provides both developer productivity and end user performance. By leveraging React Native with TypeScript for building cross-platform UI components, LinkedIn can maximize code reuse across iOS and Android. Tight integration with native platforms allows the app to retain the look, feel, and capabilities expected from native mobile experiences.
On the backend, LinkedIn stitches together its extensive services using a variety of programming languages like Java, Python, Scala, Ruby and more. Rigorous testing frameworks and continuous delivery pipelines ensure changes can be shipped reliably at high velocity. Together, these technologies allow LinkedIn to continuously innovate on its mobile app experience and provide new value to its members worldwide.