Skip to main content

SDK vs. API: The similarities and differences between an SDK and API

Ivan Vakulenko
  • Tutorial Type: Basics
  • Reading Time: 5 min
  • Building Time: N/A
Chat SDK v4 2x

Swift, Kotlin, and TypeScript SDKs

Build in-app chat, calls, and live streaming

SDKs vs. APIs: Setting the stage

Software Development Kits (SDKs) and Application Programming Interfaces (APIs) have become indispensable tools for developers in today's dynamic world of software development. These two terms frequently appear together in discussions, reflecting their shared characteristics and collaborative roles in creating and enhancing an app's features and functionalities.

SDKs and APIs possess unique attributes that distinctly differentiate their roles in the software development process. This article will delve into the purpose and significance of SDKs and APIs, shedding light on their respective functions, the reasons behind their immense popularity among developers, and the nuances that set them apart. We'll also compare SDKs vs APIs in a table, and understand the similarities and differences between an SDK and API.

What is an API?

An API is a set of protocols and instructions that facilitate communication between two pieces of software. APIs not only allow for information transfer, but also provide guidelines for how that information should be exchanged.

For example, imagine you've gone to a restaurant and need to place an order for your food. You tell the waiter what you want to order, and he communicates this to the kitchen. You do not need to know how the kitchen operates to be able to receive your food.

Similarly, in the case of software, an application (you) talks to an API (waiter) to request data (food) from the kitchen (server). The application does not need to know the intricacies of how the web server operates to be able to receive data.

API flow chart
Adapted from

APIs thus act as gateways, allowing developers to access the features, data, and services provided by external applications or platforms, resulting in a more powerful and interconnected application.

The widespread adoption of APIs in modern software development can be attributed to several key benefits of APIs:

  • Better flexibility: An API allows developers to access a service without having to implement the service itself. For example, the Stripe API allows developers to build payment functionality into their application without building the entire payment system themselves.

  • Efficient resource utilization: By allowing developers to access pre-built functionalities and data from other applications, APIs reduce the need to create these elements from scratch, leading to more efficient resource utilization and a shorter development cycle.

  • Improved interoperability: APIs enable different software applications to communicate and share data seamlessly. This interoperability fosters a more collaborative environment, where developers can build on each other's work, and applications can integrate with a wide range of services to deliver enhanced user experiences. For example, developers can use Stripe's API for payments or Sendbird's API for in-app chat. Interoperability is a core tenet of the microservices architecture, which is why APIs are widely used with microservices.

  • Easier maintenance and scalability: APIs promote modular design, making it easier to maintain and scale applications over time. As APIs allow developers to access external resources without directly interacting with their underlying implementation, changes or updates to those resources can be made without affecting the dependent application.

  • Increased innovation: APIs empower developers to experiment and innovate by providing access to various functionalities and services. This access allows for rapid prototyping and the exploration of new ideas, resulting in more innovative and user-centric applications.

Examples of APIs

Some common examples of APIs include Google Maps, which allows developers to integrate maps and location services into their applications, and the Stripe API, which provides tools for developers to add payment capabilities to their applications. Other examples include the Facebook API, Twitter API, and Amazon Web Services (AWS) API.

What is an SDK?

An SDK is a set of tools, or all-encompassing packages, for developing software applications for a specific platform (such as Android or iOS) or programming language (such as JavaScript, Kotlin, or Swift).

For example, imagine that you want to bake a fancy cake but lack the time and skill to do so. You might then use a cake mix, which contains all the ingredients in the right proportions, and add only the finishing touches.

Like a cake mix, an SDK contains all the tools you need to develop your software application or add an important feature. If you use the Mixpanel SDK to embed rich analytics into your application, for example, you will have all the resources you need to build - all you need to do is add the final touches.

SDKs provide a wealth of resources that streamline the development process. An SDK may contain the following:

  • Precompiled libraries: SDKs include precompiled libraries that contain commonly used functionalities, eliminating the need for developers to write repetitive or complex code. These libraries can be easily integrated into an application, saving time and effort during development.

  • Development tools: SDKs feature a suite of development tools that aid developers in various aspects of software development, such as debugging, testing, compiling, and building applications. These tools simplify the development process and help ensure that the application runs smoothly on the target platform.

  • Documentation and support: Comprehensive documentation, guides, and tutorials provided in SDKs equip developers with the knowledge and best practices needed to utilize the SDK and its components. This support minimizes the learning curve and ensures developers can maximize the available resources.

  • Code samples and sample applications: SDKs often include code samples and example applications that showcase the SDK's capabilities and demonstrate effective use of its features. These examples serve as valuable reference points and can inspire developers as they work on their projects.

Examples of SDKs

Some common examples of SDKs include the Android SDK, which provides tools and libraries for building Android applications, the iOS SDK, which enables developers to build applications for Apple's iOS platform, and the Unity SDK, which provides tools for building games and other interactive content for various platforms. Other examples include the AWS SDK, Facebook SDK, and Microsoft Azure SDK.

Android SDK Diagram
Android SDK Diagram adapted from

The symbiosis between SDKs and APIs

SDKs and APIs are complementary tools that work together to create a powerful development ecosystem. Many software developers use SDKs and APIs to accelerate their development process and build feature-rich applications, highlighting the increasing reliance on these tools in the fast-paced world of software development.

By combining the strengths of both, developers can enjoy the following advantages:

  • Accelerated development: SDKs' pre-built components and tools, coupled with the functionality and data access enabled by APIs, significantly accelerate the development process. This combination allows developers to focus on creating unique application features and functionalities rather than getting bogged down in low-level details.

  • Enhanced flexibility and customization: SDKs provide a solid foundation for developers to build upon, while APIs enable seamless integration with external services and applications. This synergy allows developers to create highly customized and flexible applications that cater to specific user needs and preferences, resulting in more engaging and user-centric experiences.

  • Streamlined updates and maintenance: The modular design promoted by APIs and the comprehensive resources provided by SDKs simplify updating and maintaining applications. Developers can easily implement changes or improvements to their applications without modifying large portions of the codebase, ensuring that the applications remain up-to-date and aligned with evolving user demands.

  • Interoperability and collaboration: The combination of APIs and SDKs fosters a more interconnected and collaborative software development environment. APIs enable seamless communication between applications, while SDKs provide the necessary tools and resources to build applications compatible with various platforms and environments.

SDK vs. API: Major differences

While both SDKs and APIs play crucial roles in software development, it's essential to understand the distinctions between these two tools.

SDK vs. API: A head-to-head comparison

SDK vs. API comparison table

Functionality of SDKs vs. APIs

SDKs and APIs serve different purposes within the software development process.

SDKs are comprehensive toolkits designed to support the development of software applications for a specific platform or environment. They include resources such as libraries, development tools, documentation, sample code, debuggers, or a compiler. This simplifies the development process and helps developers create applications that are compatible with the target platform.

APIs are interfaces that enable communication between different software applications, allowing them to share data and functionalities. They provide a standardized way for developers to access external resources, such as third-party services or other applications, without having to understand the underlying implementation details.

Implementation of SDKs vs. APIs

SDKs and APIs differ in how they are implemented and integrated in an application:

SDKs are integrated into an application through the inclusion of libraries and other resources provided by the SDK itself. These resources can be directly incorporated into the application's source code, allowing developers to access platform-specific APIs and other functionalities in an efficient way.

APIs are typically accessed through API calls or requests made by the application to retrieve data or access specific functionalities. These calls are usually made using standard protocols, such as HTTP for web APIs, and require the developer to include the appropriate code in their application to interact with the API.

Platform compatibility for SDKs vs. APIs

SDKs and APIs also differ in terms of their platform compatibility.

SDKs are typically platform-specific and designed for use with a particular platform or environment. This ensures that the resources provided by the SDK are compatible with the target platform, but it may also limit the SDK's usability across different platforms and programming languages.

APIs can be platform-agnostic, meaning they can be used across various platforms, programming languages, and frameworks as long as the API is properly implemented and called within the application. This flexibility allows developers to access the same data and functionalities regardless of the platform they are working on.

Unleashing the combined power of SDKs and APIs

SDKs and APIs are two indispensable tools in modern software development that serve unique and vital roles in shortening an application's development cycle. The symbiosis between them provides developers with a powerful development ecosystem that promotes accelerated development, enhanced flexibility, streamlined maintenance, and improved collaboration. For more information about APIs, please see this guide which offers an overview of the various types of APIs, as well as API architecture and communications protocols.

Whether you are a seasoned or novice developer, you can start exploring Sendbird's SDKs for in-app chat (you can use SDKs for iOS, Android, JavaScript, Flutter, and more!). If you'd like to build in-app chat with all the features of a modern messenger without sacrificing control over your data or user experience, start a free trial. There's a plethora of documentation and tutorials available for you to start building right away. If you want to take your chat app to the next level, you can do so with Sendbird Calls and Live. Contact us if you need further assistance - our experts are always happy to help!