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What is a SDK? The difference between API and SDK explained 

Ilia Lotarev

February 19, 2024

20 min read



Code samples are the bedrock of current website and app development, as the collective experience grows and more teams enter the market. That’s why, even with plenty of instructions and now even AI tools, modern code at most companies is a patchwork collected from different sources rather than a cohesive entity. It works when it works, and when it doesn’t — well, let’s hope it doesn’t come to that.

This approach, however, might lead to unstable work and an uncomfortable user experience. That’s why a lot of user-oriented platforms and services introduce Software Development Kits or SDKs. They tend to simplify the process for developers and ensure a seamless user experience.

In this guide, we will discuss the SDK benefits in full detail, explain the differences between SDK and API, and show why the Adapty SDK is a must-have for your app. Let’s go!

What is a software development kit, or SDK?

A Software Development Kit (SDK) is an essential collection of software tools and programs that you can utilize to create applications for specific platforms, operating systems, or hardware. It serves as a comprehensive package designed to simplify and streamline the development process, enabling you to build sophisticated and efficient applications more effectively.

Its key component, code samples, provides practical examples of how to implement specific features or solve common problems. These samples act as a valuable learning resource, especially for new developers or those new to a particular platform, demonstrating best practices and guiding them through the process.

SDKs also come equipped with extensive documentation that offers detailed instructions and guidelines on how to use the tools and components within the SDK effectively. It covers everything from setup and installation to specific use cases, helping developers to understand the capabilities and limitations of the SDK.

Inside an SDK are tools, components, libraries, and instructions: everything you can use to speed up the development process. Let’s see what a typical SDK might pack inside.

Tools in a software development kit

SDKs are equipped with a variety of components, each designed to support different aspects of the application development process. Here’s a closer look at some of the common components found within SDKs:

  1. Compilers convert your code into an executable file: a program or an app. They translate the high-level programming language into machine code or a lower-level language that the computer’s processor can understand. This process enables the creation of executable applications from the source code. Compilers also perform optimizations to improve the efficiency and performance of the resulting software.
  2. Debuggers assist developers in identifying and resolving errors or bugs in their code. They allow developers to run their applications in a controlled environment where they can inspect the current state of the program, track variable values, and step through code line by line to understand how the application behaves at runtime. Some SDKs also include specific tools for testing or sandboxes.
  3. Many SDKs include or provide support for an Integrated Development Environment (IDE). An IDE is a comprehensive application that provides developers with a user-friendly interface for coding, compiling, debugging, and sometimes deploying their applications. IDEs typically feature a code editor, tools for building and debugging, and often integrate with version control systems. A typical example of this is Xcode by Apple.
  4. Libraries are collections of pre-written code that developers can use to add specific functionality to their applications without having to write it from scratch. These can include graphical elements, data manipulation functions, or connectivity features, among others.
  5. APIs (Application Programming Interfaces) define a set of rules and protocols for building and interacting with software applications, enabling different software components to communicate with each other. Libraries and APIs significantly speed up development by providing reusable components and interfaces.
  6. Comprehensive documentation is a must for any SDK. It typically includes API reference guides, installation instructions, feature descriptions, and usage guidelines. Tutorials and sample code, often included with the documentation, offer practical examples of how to implement features, guiding developers through common scenarios and helping them to learn the SDK’s capabilities.

All these components help speed up the development and lower the barrier to entry for new platforms and services. Now, let’s talk about some less obvious benefits of using an SDK.

What are the benefits of an SDK?

SDKs Speed Up the Development Process. SDKs offer a suite of pre-built tools, libraries, and code samples that developers can leverage, thus avoiding the need to create basic components from scratch. For instance, if you develop a mobile game using the Unity SDK, you benefit from advanced graphics rendering, physics engines, and networking libraries, allowing them to focus on game design and user experience rather than underlying technical complexities.

Provide Standardized Procedure. SDKs collect best practices and typical procedures for app development, ensuring that developers follow a consistent approach. This standardization is especially beneficial in large teams or when integrating third-party services. For example, the Google Maps SDK ensures that developers can implement maps and location features following Google’s recommended practices, leading to a consistent and reliable user experience across apps.

Ensure Compatibility with the Target Platform. Some SDKs are specifically designed for their respective platforms, ensuring that applications built with them are compatible and perform optimally. If you want to create an app for the Apple Watch, you would use the relevant SDK (also known as WatchKit), which includes tools and interfaces tailored to the watch’s unique hardware and software environment.

Reduce Costs. SDKs make it significantly less costly to develop: you decrease development time, minimize the need for extensive testing across different platforms, and avoid purchasing individual tools or libraries. For example, a startup developing a cross-platform mobile application can utilize the Flutter SDK, enabling them to write the code once and deploy it on both iOS and Android platforms, reducing both development and maintenance costs.

Now that we ’sold’ you the benefits of SDKs, let’s see how to deploy them in action.

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How does an SDK work

Here is a simplified walkthrough of the steps a developer might take when starting with an SDK:

  1. Select the Right SDK. The process begins with assessing the needs of the project. You should base your choice on the target platform (iOS, Android, Windows, etc.), the specific capabilities (e.g., graphics, networking, database management), or industry-specific features (e.g., payment processing for e-commerce, GPS for location-based services).
  2. Once selected, download and install the SDK of your choice. For integrated development environments (IDEs) like Xcode or Android Studio, the SDK may come pre-installed or be available as a downloadable component within the IDE.
  3. The next step is to set up your development environment to use the SDK. This could involve setting path variables, configuring IDE settings to recognize the kit, or importing necessary libraries and frameworks into their project. The setup process typically follows documentation provided with the SDK.
  4. Explore Documentation and Sample Code. Before diving into development, familiarize yourself with the documentation and explore available sample code. Documentation should briefly explain SDK’s capabilities, API references, and guides on how to use various components, while sample code will present specific features and best practices.
  5. Start Development. Go as you were, only now armored with new features, libraries, and capabilities. Integrate SDK components into your codebase, leveraging the functionality provided to enhance their application.
  6. Test and Debug. SDKs often include tools for testing and debugging applications. Use these tools to test applications in various conditions, identify and fix bugs, and ensure the software runs smoothly on the target platform. Debugging tools provided by the SDK can help trace issues back to their source, making it easier to maintain code quality.
  7. Deploy: this is the easiest part! The SDKs often include tools for packaging the application, meeting platform-specific deployment criteria, and automating the deployment process. Following the SDK guidelines for deployment ensures the application is compatible with the target platform and meets any necessary distribution standards.wd7bsKBDdl0wM1QEa1kjCe KoAOqUCYPSrts0eHJH6QLNJLquH2gVZPSPH1C1ugRI2f8LLM3qUWpWil6L28HXUcPlMD0N0Cli3tD7gfnFwtYoYgee

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What makes a good SDK?

There are several key criteria to consider when assessing the quality of an SDK

Ease of integration is key when choosing an SDK. It should smoothly fit into your existing development environment with a hassle-free setup and minimal configuration. Whether you’re working on a small project or a large-scale application, the SDK must be compatible with the tools and platforms you’re using. Its flexibility means you can adapt it to various project requirements, making your job as a developer easier and more efficient.

Documentation can make or break your experience. Look for clear, comprehensive guides that cover everything from initial setup to advanced features. Good documentation is well-structured and easy to navigate and allows you to quickly find answers and solutions. It should serve as a reliable reference that betters your understanding and usage of the kit, not as a source of frustration.

A strong community support system is always a plus. Fellow developers can provide insights, help solve challenges, and share their experiences. Look for vibrant forums, detailed tutorials, and an abundance of code samples. These resources are a testament to the SDK’s credibility and the robustness of its user base, offering you a safety net of collective knowledge.

Regular updates and maintenance are crucial indicators of a kit’s longevity and reliability. Frequent releases that introduce new features, bug fixes, and performance improvements show the provider’s dedication to staying current and responsive to developer needs. However, the balance between innovation and stability is essential; updates should not disrupt existing projects but rather ensure backward compatibility and enhance the SDK’s value over time.

It goes without saying that the SDK should be reliable and consistently perform well under various conditions without introducing bugs or slowing down your application. An optimized SDK won’t just speed up development time but also ensure that your application runs smoothly, providing a better experience for your end-users.

An intuitive design and user-friendly tools within the kit can significantly boost your productivity. Features like code completion, integrated debugging, and performance analysis tools should be at your fingertips to streamline your workflow. A well-designed SDK not only makes development more pleasant but also helps you deliver quality applications faster.

And of course, the SDK should include strong security measures to safeguard your application from vulnerabilities. Additionally, it must comply with relevant industry standards and regulations, ensuring that your application meets the necessary legal requirements. This peace of mind allows you to focus on innovation rather than mitigating security risks.

Another key point before we move on to the next topic: the user experience provided by a kit directly influences developer productivity. An SDK that is easy to use, well-documented, and supported by a strong community can significantly reduce development time and effort. It allows you to focus on creating unique features and solving business problems rather than wrestling with integration issues or searching for information.

Difference between SDKs and APIs

In short, an API (Application Programming Interface) is a set of rules and specifications that allows software applications to communicate with each other, enabling the integration of and interaction between different software components. In contrast, an SDK is a comprehensive suite of tools that may include APIs, libraries, documentation, and other utilities, designed to facilitate the development of applications for a specific platform or technology. 

While both SDKs and APIs are essential in the development process, they serve different purposes and complement each other in facilitating software creation and integration.

SDKs are distinctively crafted to cater to the needs of specific platforms or technologies, exemplifying platform specificity in their design and utility. For instance, the Android SDK is specifically designed for the development of Android applications, equipping developers with the necessary tools and APIs to efficiently interact with the Google mobile operating system. 

Software Development Kits (SDKs) and Application Programming Interfaces (APIs) serve distinct yet complementary roles in the software development ecosystem. SDKs offer a comprehensive suite of tools and components, including APIs, which are essential for building applications from the ground up. They are particularly beneficial when embarking on new projects or when developing applications for specific platforms or technologies. An SDK streamlines the development process by providing developers with all the necessary tools, libraries, and APIs, ensuring a cohesive development environment tailored to their project’s requirements.

APIs, on the other hand, stand out for their role in facilitating communication and data exchange between different software components or services. Whether used within an SDK or as standalone interfaces, APIs enable interoperability between applications, allowing them to share data and functionality seamlessly. Here are the key API features in more detail:

  • APIs facilitate the exchange of data and commands between different software systems, allowing applications to leverage features provided by other apps, services, or platforms.
  • APIs integrate disparate systems, making it possible to combine data and functionality from multiple sources seamlessly. 
  • Through APIs, developers can create reusable components. This means that once a functionality is developed, it can be made available to other applications via an API, reducing redundancy and fostering a modular approach to software development.
  • APIs allow for customization of existing products and services. Developers can build on top of existing platforms, tailoring functionalities to meet specific requirements without starting from scratch.
  • APIs can also control access to software components or data, ensuring that only authorized requests are processed. This adds a layer of security by encapsulating the application’s internal structure and only exposing what is necessary.

What can Adapty SDK do?

Adapty helps mobile app developers earn more by optimizing their subscription-based business models and simplifying the deployment of revenue-generating paywalls. The Adapty SDK is tailored to facilitate in-app subscription management, analytics, and revenue optimization. Here are its key features:

  • In-App Subscriptions Management. The Adapty SDK simplifies the process of implementing and managing in-app subscriptions across iOS and Android platforms. It provides a unified API that handles various subscription scenarios, including trials, renewals, cancellations, and cross-platform subscriptions, making it easier for developers to manage the lifecycle of subscriptions within their apps.
  • Analytics and A/B Testing allow developers to track subscription performance, analyze user behavior, and understand revenue trends. Additionally, the A/B testing feature enables developers to test different subscription offers, pricing strategies, and promotional messages directly within their app, helping to optimize conversion rates and increase revenue.
  • Adapty allows developers to configure and update paywalls in real-time without the need to release app updates. This feature provides significant flexibility in modifying subscription offers and responding to market changes quickly, enhancing the ability to experiment with and optimize monetization strategies.
  • Cross-Platform Support: The SDK supports both iOS and Android, offering a cohesive experience for managing subscriptions across different devices and operating systems. This cross-platform capability is essential for developers aiming to provide a seamless subscription experience for their users, regardless of the device they use.

The Adapty SDK is specifically designed for apps with Subscription Offerings: whether it’s content apps (like news, streaming services, or educational content), lifestyle apps (such as fitness or diet), or any other app that offers subscription-based access to premium features or content, Adapty provides tools to manage, analyze, and optimize these subscriptions effectively.

Our SDK is focused specifically on the needs of subscription-based mobile apps. Its comprehensive toolset for managing subscriptions, combined with powerful analytics and the ability to conduct A/B tests on subscription models, positions Adapty as a specialized solution in the mobile app subscription space. Unlike more general analytics or marketing SDKs, Adapty is tailored to the nuances of subscription management, offering targeted solutions that help developers optimize their revenue and improve user engagement with their apps.

Adapty’s SDK offers a unique blend of features to simplify subscription management, enhance revenue optimization, and provide actionable insights into user behavior for subscription-based mobile apps. Its focus on real-time adjustments, cross-platform support, and in-depth analytics makes it a valuable tool for developers looking to thrive in the competitive world of app subscriptions.

Key takeaways

Wrapping up our exploration of Software Development Kits (SDKs), it’s easy to see that SDKs are indispensable tools in the software development world, offering a bridge between raw coding potential and the creation of polished, platform-specific applications. They simplify the development process and empower developers to focus on innovation and efficiency, all while ensuring compatibility and performance.

Here’s what you need to remember:

  • SDKs provide a comprehensive set of tools for developers, including libraries, documentation, and APIs. They streamline the application development process, making it more efficient and effective.
  • SDKs are tailored for specific platforms or technologies, ensuring compatibility and optimization.
  • APIs are often part of an SDK, and the distinction is easy: SDK offers a broader toolkit for development and APIs focus on communication between software components.
  • Specialized SDKs, like Adapty, cater to niche markets by offering targeted, single-purpose solutions that greatly simplify one daunting task.
  • Adapty SDK makes monetizing your apps with in-app purchases and subscriptions a breeze by allowing you to quickly configure and deploy paywalls.
  • Regular updates and community support are essential for maintaining the relevance and effectiveness of SDKs.
  • Ease of integration, comprehensive documentation, and reliability are key criteria when evaluating the quality of an SDK.

Hopefully, this guide was useful in your quest to become a more well-versed developer. SDKs offer a lot of great new opportunities, and Adapty SDK is here to make sure you monetize them properly. Can’t wait to see what you will come up with!

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