What is a software development kit (SDK)?
A software development kit (SDK) is a set of software tools and programs provided by hardware and software vendors that developers can use to build applications for specific platforms. SDKs help developers easily integrate their apps with a vendor's services.
SDKs include documentation, application programming interfaces (APIs), code samples, libraries and processes, as well as guides that developers can use and integrate into their apps. Developers can use SDKs to build and maintain applications without having to write everything from scratch.
More specifically, SDKs include the following components:
- Libraries are a collection of reusable and packaged pieces of code that perform specific functions.
- APIs are predefined pieces of code that let developers perform common programming tasks on the platform.
- Integrated development environments (IDEs) are visual editors that help with the design and layout of graphical elements, such as text boxes and buttons. These are common in mobile software app development toolkits. For instance, Apple's IDE, Xcode, contains a suite of software development tools to help developers build software for macOS, iOS, iPadOS, watchOS and tvOS. There are numerous IDE options for Android.
- Testing tools and compilers include debugging tools to help developers identify coding errors at various stages of application development.
- Documentation encompasses the instructions and tutorials vendors provide to help developers as they go through the development stages.
Difference between SDKs and APIs
SDKs let developers create applications and act as the building blocks for the software product. APIs, on the other hand, provide the code that enables two software programs to communicate with each other. An API defines the correct way for a developer to request services from an operating system or other application and expose data within different contexts and across multiple channels.
When a developer uses an SDK to develop applications and create systems, those apps have to communicate with other applications. An SDK includes an API to enable that communication.
Other differences between SDKs and APIs include the following:
- SDKs usually contain APIs, but APIs don't contain SDKs.
- Although an API can be used for communication, it can't be used to create new applications.
- An SDK is the tool and component piece of code that has been created for a specific purpose, while an API is an interface for a service.
How to use an SDK
A developer needs an iOS SDK to build iOS apps, an Android toolkit for building Android apps, a Nordic SDK to build Bluetooth or wireless apps and a VMware SDK to enable integration with the VMware platform.
For large-scale software-as-a-service applications, enterprises generally use the open source .NET SDK platform, which is backed by Microsoft. Other examples of popular SDKs include the Google Cloud SDK, Microsoft Windows SDK, Java Development Kit and the Node.js SDK. Although SDKs are largely associated with native mobile apps, developers can use them in connection with websites, set-top boxes and other digital platforms.
The use of an SDK typically involves the following three steps:
- A platform-specific SDK is purchased, downloaded and installed by a developer.
- The developer starts the development within an IDE. They may use the APIs included in the SDK to create new apps.
- To expedite the initial phase of development, developers use the instructions, documentation, code samples and testing tools provided in the SDK.
Benefits of SDKs
Different types of SDKs can be used for a variety of programming languages and mobile applications. By assembling the needed set of tools in one location, SDKs simplify standard processes and add more functionality to applications.
The following are the key benefits of using SDKs:
- Time saving. SDKs let developers easily and quickly build the standard components of their apps and add functionality to them. SDKs are usually all-in-one products and don't need to be integrated with other components, which can slow down the development process.
- Easier integration. Developers use SDKs for simple functions, such as logging in, location services and mobile payments. However, some SDKs help developers build more complex app features, such as augmented reality and virtual reality, and add new features. SDKs reduce the complexity of integrations by simplifying standard processes, such as creating authorization signatures and interpreting SMS messages in native languages or platforms.
- Documentation and code libraries. SDKs include documentation, tutorials APIs, code samples, libraries and processes. They also provide guides developers can use and integrate into their apps. Developers use SDKs to build and maintain applications without having to write everything from scratch.
- Enhanced functionality. SDKs let developers enhance apps with more functionality, such as push notifications and ads. SDKs also help developers create new tools and make the process easier because everything is prebuilt. For example, if a developer wants to share images or text from an app directly on Facebook, they could look for Facebook's Android SDK to find the necessary code that would work for an Android device. This speeds deployment because the developer doesn't have to write the code from scratch.
- Brand credibility. Apps supported by an SDK toolkit gain exposure as they can get published on app stores where customers search for and buy apps. These apps are less prone to unexpected crashes and have easier third-party integrations, giving them better ratings in the app store and boosting their brand's credibility.
- Cost savings. Because of their shorter development cycles, apps built with SDKs can offer substantial cost savings. In addition, SDK integrations don't require specialized technical skills, which lets organizations perform in-house integrations rather than pay to hire outside professionals.
- Customization. SDKs are available for a variety of use cases and provide the ability to develop apps with personalized user experiences.
What makes a good SDK?
Vendors and other SDK providers frequently offer many new commercial and open source SDKs, which makes it challenging for businesses to pick the right one for their needs. Price tags and specific features are a good place to start when picking an SDK. However, it's important to consider other factors, as such how user-friendly and easy to understand it is.
A good SDK should have the following characteristics:
- Easy to use. Developers shouldn't have to spend a lot of time figuring out how an SDK works.
- Functional. An SDK should have enough functionality to add value to apps.
- Documented. An SDK should provide a clear, thorough and up-to-date explanation of how the code works. Since an SDK is geared toward developers, it should also include code samples and integration examples.
- Quick integration. In most cases, an integration shouldn't take longer than five or 10 minutes, depending on the type of SDK used. A good SDK should be easy to integrate and require minimal intervention.
- Scalable. An SDK should be scalable to support the growing needs of a business.
- Battery efficient. Some SDKs can drain the battery and data consumption of a device's CPU. A good one will minimally impact the data consumption and battery life of a device.
- Secure. Researchers recently identified 1,859 apps across Android and iOS containing hard-coded AWS cloud credentials that were traced back to a vulnerable third-party SDK. An SDK should be able to secure a user's data and app information as well as follow current security guidelines.
With their immense benefits, mobile SDKs also have some pitfalls. Learn how mobile SDKs work and the pros and cons of using them.