What You Need to Know: SDKs and APIs
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What You Need to Know: SDKs and APIs

If you want to encourage a developer ecosystem, you must understand the difference between SDKs and APIs.

Any contemporary developer system is going to rely on both interfaces to provide the tools for online communications and third-party API implementation.

This article will define and layout both interfaces in relation to how they interact.

API (Application Programming Interface)

APIs are an interface that allows compatibility between different software. It’s in its name, Application Programming Interface. It’s like a translator facilitating a conversation between two languages, the two communicating software contain two different sets of instructions, and an API deciphers them to create a consensus.

There are many varieties of APIs. Any browser that a reader might use would implement several API sets to create useful functions out of a user command, request and receive data from a server, translate the data so that the user can read it, and validate the response of the request.

Basic computing functions, such as copying and pasting text, require APIs. When you copy text, an API takes a keystroke and converts it into a command. That data is then stored as RAM on the clipboard through an API, that date gets carried from application to application through the same API. At last, the data is delivered when you paste the text through another API.

Web APIs are very similar with some slight variations. A Web API facilitates interplay between different systems for specific purposes. For example, Tumblr users will use APIs when performing various task such as messaging, following/unfollowing, delete a post, etc. Simply put, Web APIs are instruction sets based online instead and on a personal computer.

The APIs most crucial quality is stability. In the “old days” of programming computers were a wilderness of loosely coded and mostly undocumented commands. APIs have brought upon stability through consistent coding, which allows for replicable function delivery that’s reliable each time.


Software Development Kits are just that, a kit. Think of when you build furniture out of the box; you need an entire kit to make it. You’d need the instructions, all the pieces that connect, the hardware that holds them in place, and the tools to secure it.

SDKs, aka Devkits, are the same as that kit. They provide the toolset, your helper library, all the applicable documentation, samples of code, etc. All this to facilitate the creation of software on specific platforms.

The Factory

SDKs can contain APIs much like in geometry the square is a subset of rectangles, all squares are rectangles, but not all rectangles are squares. APIs are like a machine that perform specific functions, and SDKs are the whole factory that contain all of the machines. If a factory makes cars the software is the car, the APIs are the machines, and the SDK is the factory. An API creates specific functions within software such as messaging, data storage, etc. Much like how a machine performs a specific function like pressing a sheet of metal into a car part. The SDK is the factory that provides all the necessary tools and materials. However, both are necessary to build the car.

Tech Examples

The Facebook solution suite is a useful example of the differences between APIs and SDKs. It provides users and developers with tools. It’s filled with SDKs and APIs with several functions and uses.

Facebook API’s

Facebook API is used internally and make use of third-party application providers. This creates communication across Facebook’s network. When this occurs, social connections and information from personal profiles are used for Facebook’s application functions.

These functions are features such as moving profile activity to users’ main feeds, profiles, or including third-party applications such as external websites or media platforms. Data is collected, combined, and then used to create personal connections on Facebook’s platform to better the company’s service. The sources of this collation area combination of photos, profile pages, events, friend networks, and group data.

source: https://developers.facebook.com/docs/marketing-apis/


This function restricts the media sharing of users’ data, allowing for individuals to monitor and limit the content on their profiles and what data is being shared. This additional API security enables the individual to access multiple data points while retaining secure privacy as a social media user.

This API function goes further than simply the internal benefit of the Facebook user. Graph API Explorer is one of API’s strongest features by allowing relational data to be observed across data points of users, profiles, photos, videos, etc. This metric of API is a substantial benefit for API providers.

1      GET graph.facebook.com

2  /me?

3  fields=albums.limit(5){name, photos.limit(2){name, picture, tags.limit(2)}},posts.limit(5)

In this example, API issuance can be observed. This instance shows API being applied to access a user’s photo, the URL of that photo, and anyone tagged in the photo. This is just one example of the vast amount of applications that API could be used for in the fields of promotion and consumer engagement.

Aside from Graph API, Facebook has shared Marketing API, which is built to help companies engage with consumers through product campaigns on a social platform. This API illustrates the power of Facebook’s platform as well as the effective use and structure of API design.

The benefit of an effective structure is evident in the interaction between Marketing API and CPM (Cost per mile). The cost/value of user interaction is used by advertisers to effectively and efficiently market and advertise their products.


use FacebookAds\Object\AdSet;

use FacebookAds\Object\Fields\AdSetFields;

use FacebookAds\Object\Values\BillingEvents;

use FacebookAds\Object\Values\OptimizationGoals;


$adset = new AdSet(null, ‘act_’);


  AdSetFields::NAME => ‘My Ad Set for oCPM’,

  AdSetFields::BILLING_EVENT => BillingEvents::IMPRESSIONS,

  AdSetFields::OPTIMIZATION_GOAL => OptimizationGoals::LINK_CLICKS,

  AdSetFields::BID_AMOUNT => 150,

  AdSetFields::CAMPAIGN_ID => ,

  AdSetFields::DAILY_BUDGET => 1000,

  AdSetFields::TARGETING => array(

    ‘geo_locations’ => array(

      ‘countries’ => array(











Here the second example of API can be seen where Marketing API created an advertising campaign that can be bid on by users within the restraints of the budget values of the campaign. This kind of bidding enables a system of API that is effective and optimized towards the user’s CPM to collect the best value impressions and keeps track of Return on Investment.

This system of bidding shown in the example above creates the most optimized ROI; the source of this efficient ROI is a carefully crafted API.

Facebook SDKs

The variance of a function of API and SDK on Facebook is the most significant distinguishing factor between the two. API, created as an interface between users and applications, differentiates itself from Facebook’s SDK, designed to create these applications.

Facebook’s SDK on IOS is crafted to allow the platform’s IOS applications to be developed. More than one feature of SDK can be defined and called on IOS. Here is an example of code from the SDK reference guide for Facebook’s IOS:

//  AppDelegate.m

#import <FBSDKCoreKit/FBSDKCoreKit.h>

– (void)applicationDidBecomeActive:(UIApplication *)application {

  [FBSDKAppEvents activateApp];


In this instance, the application’s activations log is listed. API and SDK drastically differ even in a general example such as this in that API takes applications and functions to perform actions on Facebook while SDK creates these applications so that the API can use them.

Similar to IOS, Android’s SDK has the same function but instead is translated into Android’s OS format. More significant variations from IOS SDK can be found in web programs such as JavaScript SDK. The same SDK of Android and Apple is seen in JavaScript, but instead, the function is performed through the JavaScript program.

To further explain the differences between SDK and API, one can visualize SDK as the building blocks or foundation of the application that API is the language of. This illustration continues to be clarified if one observes the components of the SDK. SDK component examples include libraries use to build SDK’s functionality or its references which provide simple links and descriptions. While SDK function could survive without such elements, the service would be mostly limited and far less effective.


There is confusion when comparing between API and SDK because of the overlap of the two functions. This lack of clarity in comparison only worsens with the modern methods and organization of their features. The following are some clarifying, simplifying contrasts between the two:

  • APIs are a part of SDKs while SDKs are not a part of APIs (see the section above on rectangle and square analogy)
  • APIs allow application functions within the parameters defined by SDK
  • SDKs are responsible for creating applications (SDKs are the foundation of a building, APIs are one of the building components of that building)

Hopefully, this article provided a better understanding of Facebook’s API and SDK and how they differ from each other!

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