A Guide To API Development
API development is not only a technical activity but a critical aspect of contemporary software design. No matter what you are developing—a web app, a mobile app, or a system of systems; APIs are always necessary. They make it possible for software components to communicate, thus creating functionalities that would otherwise be impossible. This means our guide will walk you through the entire process of API development from the ground up, all the way to the most complex topics and strategies.
What is API
An API, or Application Programming Interface, defines how two or more software applications can interface. It serves as a middle layer through which different programs involved in the chain can intercommunicate and share information and processing capabilities.
APIs specify how an application can request information and the structure of the data that is to be exchanged with other applications, thus providing a structured way for different systems to communicate.
Why is API Development Important?
There are several reasons why API is very important in contemporary software development:
- Integration: APIs easily interlink various apps and services, enhancing the connectedness of the digital world.
- Efficiency: It is easier for developers to use the APIs than having to code everything from the root level.
- Innovation: APIs allow new applications and services to build upon existing functionalities uniquely.
- Scalability: APIs should be designed to easily accommodate a large number of users and customer requests to the application.
- Security: APIs offer well-protected and well-regulated means to enable applications to access data and functionalities, which can help protect data that is not easily accessible.
How does API Work?
APIs function like rules for how various parts of a program should behave. If an application needs to use data or services of another application, it requests the API. This request is in the proper API format and contains all the details, including authentication information and the data being sought.
The API then handles this request, fetching the necessary data or performing the expected action. When the API is done processing the request, it returns a response to the application that made the request. It must contain the requested data or a message that the action has been performed successfully.
This process occurs out of sight of the end-user, unaware of the elaborate communication between the various applications.
Types of API
Many APIs are available in the markets to fulfill open and highly customized development requirements. Based on their scope of use, APIs can be classified into four categories.
1. Private APIs
Internal APIs are also known as internal APIs; they can be accessed only by an organization’s employees. These are suitable for linking every data and business system. Some of the best examples include APIs integrating the payroll and other organizational human resource applications.
Private APIs do not have security requirements, so they have very poor levels of authentication and authorization. The security levels of overall business systems are sufficient to handle these APIs that are only functional internally.
2. Partner APIs
As the name suggests, these APIs are for B2B use only. Therefore, partner APIs are unique to certified and particular developers and not open to all developers. The most appropriate use of partner APIs is the APIs that provide access to the customer data to other CRM firms. Therefore, these are with authorized access, and no APIs are utilized from the outside. All these APIs are provided to the license holders only. Compared to all APIs, partner APIs have high levels of authentication, security mechanisms, and authorization.
3. Public APIs
These APIs are open, meaning anybody can use them to develop applications. Therefore, several companies that want to provide API for development only utilize the public API, which is accessible to everyone. These APIs operate on moderate authorization and authentication. Businesses can earn by charging for their public APIs and can earn from per-call charges.
4. Composite APIs
These APIs integrate two or more types of APIs. This combination greatly improves functions and results in high levels of optimized performance. Composite APIs are designed to meet specific needs that individual APIs cannot fulfill in the various businesses that different organizations entail.
Architectural Styles of API Development
API development encompasses diverse architectural styles where the specific style is effective in specific situations. Knowing these styles is important when deciding which style suits your API development project.
1. Web APIs
Web API is also called HTTP API since it is designed to be consumed over the Internet through HTTP protocols. Web APIs are for general purposes and can be utilized by any client, whether web browsers, mobile applications, or server-side applications. They employ JSON or XML as the medium of data exchange and are considered easy to implement.
2. SOAP (Simple Object Access Protocol) APIs
SOAP APIs utilize XML to create the message format and employ HTTP, SMTP, or TCP protocols to transfer the message. High standards characterize them and can check for errors. SOAP APIs are frequently utilized where service level agreements between services need to be formally defined. They are comparatively easier to implement than other API styles and provide a strong means for security and reliability.
3. GraphQL APIs
GraphQL is a query language for APIs that enables clients to request the necessary information. In contrast to REST APIs, where the structure of the answer for a specific resource is predetermined, in GraphQL APIs, such a decision is made by the client. This flexibility means that data is only fetched when required and not when it is not needed, thus avoiding over-fetching or under-fetching.
4. Streaming APIs
Streaming APIs are those which share information in real-time. They establish a sustained relationship between the client and the server and allow data exchange at any one time. This type of API is most appropriate for the applications where the data is changing in real-time, such as stock tickers, social media feeds, or smart devices.
5. RPC API (Remote Procedure Call API)
RPC APIs depend on the actions rather than resources. They are designed to make a call to a procedure or function on a server and execute as though it is a local call. Regarding the protocols, there are two protocols for RPC APIs: XML-RPC and JSON-RPC. They are often used in distributed computing systems where simplicity and high performance are often regarded as primary objectives.
6. REST (REpresentational State Transfer)
REST is an architectural style that has gradually developed to become the most widely used style for web APIs. Interaction with the resources in RESTful APIs happens using standard HTTP methods of GET, POST, PUT, and DELETE. They are without state, cacheable, minimalist, and extensible. JSON is the main format of the exchanged data in REST APIs and is suitable for use with various platforms and programming languages.
Terminologies of API Development
The following are the most common terminologies used in API development that one needs to understand clearly when venturing into API development.
1. API Key
API Key is a number that is used to authenticate a user, developer or an application that is requesting to use an API. It is a code that is passed in by the calling program in the process of communication with an API to indicate the calling program, its author, or its patron. API keys are useful when the provider of the API wants to regulate or track the usage of the API when the API is being misused.
2. Endpoint
An endpoint is a specific API, a URL to which an API can be addressed. It takes place at the interface of a channel of communication involving two systems. Every endpoint is the starting point from where APIs can obtain the requirements that will allow them to accomplish their role.
3. JSON
JSON is a data format aimed at exchanging data between a server and a web application. Even a computer and a programmer can easily comprehend the said idea. It is originated from JavaScript scripting language and is predominantly used for data transfer in web applications.
4. GET
GET is one of the HTTP methods used in RESTful APIs. This is required when it is necessary to process the data located in a specific resource. This should mean that GET requests should only be used to request data and should not in any way change the data.
5. POST
POST is the other HTTP method used in RESTful APIs besides GET. This is used to convey data for creating or modifying a resource. The data passed to the server using POST is included in the body of the HTTP request sent to the server.
6. OAuth
Web OAuth is an open standard for access delegation, and it falls under the general term of OAuth it is used today as a way through which internet users can allow certain websites or applications to have access to details they have on other websites without having to provide those websites or applications with their passwords. It is considered as one of the most important factors in API security.
7. REST
REST is an architectural style that provides protocols between the web systems so that the systems can communicate with each other better. Any system that implements REST principles is referred to as a RESTful system and can be described based on stateless and client-server distinction.
8. SOAP
SOAP is a standard for messaging that is used in computer networks to implement web services by transferring structured data. It uses the message format of the XML information set and relies on the application layer protocols, the most frequently used of which is the hypertext transfer protocol (HTTP). However, some of the older system uses the simple mail transfer protocol (SMTP) to conduct message negotiation and transfer.
9. Latency
When talking about APIs, latency refers to the time it takes for a request to be made for the request to get to the server and the time the server takes to process the request and send the response back to the client. This is crucial for the APIs that need to have a response time of real-time or almost real-time.
10. Rate-Limiting
This is the process of controlling the amount of traffic that passes through an NIC, either by sending or receiving. It can be applied to prevent DoS attacks or to limit the number of API requests depending on the user’s role.
11. API Throttling
API throttling is the limiting of how often a user can make API requests within a specific time interval. This is done to ensure that many requests cannot be made in a single instance so that the API does not get flooded with many requests. If the limit is crossed, the API may return an error or may not handle the request until the next period.
Tools For API Development
Different tools are required during API development’s design, documentation, testing, and deployment phases.
1. Apigee
The one comes from the tech giant Google, an API management provider that resets an API-integrated approach. In the case of Apigee, several developers and entrepreneurs apply it to support their digital transformation.
2. APIMatic and API Transformer
These tools also offer strong auto-generation capabilities to produce API code samples and good SDKs. Apart from the code snippets and SDKs, API Builder and API Transformers convert the code into formats like API Blueprint, RAML, etc.
3. API Science
API science is not something that one can easily come across but an equation for APIs that provides principles of how APIs can be designed, built, and controlled for the sake of understanding ability.
4. API Serverless Architecture
It integrates them with what is called serverless computing. However, while the servers are self-managed, your code only runs when an API call is made and runs in response to the call made. It is about getting faster development, automatic scaling for traffic management, and cutting down on expenses. It is suitable for building the newest and most efficient APIs since it has various features that allow the creation of efficient APIs.
5. API-Platform
An API management platform can also be defined as a system that handles all the API’s life cycle processes. This category includes API designing, development, documenting, deploying, and monitoring all the processes. I would compare it to being at the very core of all the API activities.
6. Auth0
A cloud platform that shall serve the purpose of safeguarding an app as a security guard does to a house. This way it deals with the user credentials and permissions so that the users can attempt to devise unique features. Also, it simplifies the login process, grows to achieve requirements, and shields your applications.
7. ClearBlade
ClearBlade is a design and operational platform for Internet of Things (IoT) APIs. Its tools enable the developers to connect devices, aggregate data from sensors and manage them with the help of APIs. Through ClearBlade APIs, one can create applications to communicate with these IoT devices efficiently and securely.
8. GitHub
It is similar to the GitHub repository service that is based on open source and intended for professional code storage. GitHub is used to manage code files and versions, comment on and use pull requests, and so on for a team and for storing codes in a private repository.
9. Postman
Thus, the API can be created and tested by the users through Postman and documented as well. You can go ahead and accept it as a one-stop shop for all your API creation and management needs. Nevertheless, you are free to use Postman to create requests, check responses, and collaborate on creating great APIs with great tests.
10. Swagger
It is a toolset that helps in the creation, documentation, and description of the APIs. Swagger enables you to describe what your API does, how you can regulate it, and what it requires. This makes consuming and implementing your API as easy as possible for other developers.
Must-Have Features Of An Efficient API
APIs are implemented in almost any web or mobile application. Consequently, it may be quite puzzling when looking for or developing a layout that meets the desired specifications. Following is the list of the mandatory characteristics of any efficient API
1. Modification timestamps/Search by criteria
One can add that any API should be considered as one that lacks modification timestamps or search by criteria; ideally, such options are considered one of the API’s requirements. It enables modification such as editing, altering, or sharing after the initial upload or, the first data synchronization. Additionally, APIs should allow for searching users based on data.
2. Pagination
It is another important feature that assists in getting a sneak peek of data changes and alerts on the number of data pages that are pending. It aids API in establishing how much data to present at a time and the rate of presenting it.
3. Sorting
It allows data to be sorted according to various characteristics, such as time, and makes the end-user receive one page of data at a time.
4. JSON Support / REST
JSON support helps the developers pull the API to any other language since it resembles most of the languages. It is on record that REST APIs are light and stateless and that retry features are present in mobile data upload.
5. Authorization and Authentication
Authentication like OAuth, OAuth2, and JSON Web Token or JWT. Authorization involves checking for the permission of the user to access, while authentication only involves the identification of the user.
6. Cache
Some of the requirements include The need to retrieve resources at a fast rate. Several techniques allow the integration of caching into APIs, which means that the request costs are further simplified as the data collected is already in the in-memory database.
7. Wrappers
These are the specific packages or containers in APIs that are language-bound. It can make as many calls to APIs as needed and therefore, can be said to integrate one set of APIs with another even when there is no direct user input.
8. HATEOAS
It is one of the well-known modules of REST application architecture and represents the abbreviation ‘Hypermedia As The Engine Of Application State’. Hypermedia refers to videos, images, text, etc. With its help, users can interact with REST API using the dynamic responses from the server.
9. Error handling
Debugging should be eased, and one should be able to distinguish whether it is a server-side error or a client-side error. Some of the approaches, that can be applied, include the use of well-known standards, the right number of errors, causes, and segregation of domains, etc.
10. Validation
Validating the input is essential to avoid passing incorrect or malicious data to your API. This also entails checking data types, formats, ranges, and other API constraints.
11. Testing
Testing is a very important activity that must be performed to guarantee the stability of your API. This encompasses component testing, where individual components of the API are tested; integration testing, where it is tested whether different parts of the API are working correctly; and end-user testing, where the API is tested in different real-life scenarios. Automated testing is useful for detecting problems at the early stages of development and preventing newly introduced changes from affecting the existing functionality.
12. RESTful Design
It is best to stick to RESTful design principles when designing an API to make the API more usable. This includes using known HTTP methods (GET, POST, PUT, DELETE) correctly, organizing your API around resources, and using proper names for the points of API interaction. Overall, a good RESTful API is easier to grasp for developers and will be adopted faster.
13. Versioning
Versioning is critical to API design since it enables developers to build on prior versions and make enhancements without breaking compatibility. If you allow version information in the URL or the headers of your API, you can introduce new features or make changes that still do not affect the existing uses of the API. This makes it possible for clients to stick to previous API versions while migrating to new ones.
14. Webhooks
Webhooks are a powerful feature that enables your API to send real-time updates to clients instead of having the client check for updates frequently. This can greatly minimize such scenarios and help to offer a better response time to users who depend on the latest data obtained through the APIs.
15. Documentation
Documentation is essential for API, and it should be complete and updated. The documentation should also contain descriptions of all endpoints, formats of requests and responses, all methods of authentication, and even code samples. Some formats, like Swagger, can enable interactive documentation, where developers can test your API from the documentation.
How To Start Developing An API?
Let us start by establishing the fact that the time required to create an API can range from minutes, and in other cases, it can take months, depending on the API and the tools to be used.
Now, let’s discover the steps for API development.
1. Define API’s Objective
First, it is necessary to state the purpose of API creation. You should decide on the information/data or functionality that you want to make available through the API. To sum it up, when explaining to a layman, you should define what API is and what it does.
2. Select the Technology that fits the best
Select the framework and the programming language that best fits the business needs of a company. Some of the most used are Python, Node, ASP.NET, PHP, JS, and Ruby on Rails.
3. Design API’s Endpoints
Add the missing URLs and methods that can be used to send requests to your API and get data. This will ensure that you have well-defined definitions for your users, especially those who are trying to interact with your API.
4. Implement the Logic
The next step is to develop the code that boosts your API. They will take requests, process data compute the data, and then return the output to the user.
5. Test the API
Exacting the performance of your API to the optimum should be done to ensure it meets the expected performance. Once that is done, prepare it to be deployed to a server environment where developers can come and integrate.
6. Document Your API
Now, write clean documentation of the API so that the developer can observe how to use it. This includes details on data models, endpoints, error codes, and, methods of authentication.
7. Deploy the API Securely
Security authorization and authentication methods are used to control access to your API and data. After that, select a hosting plan and make your API available to developers.
8. Monitor and Maintain
Keep an eye on the API and be prepared to look for issues and new features/changes in the API documentation based on real user needs.
This is how you can develop an API for your business, how you can modify it according to your requirements, and how you can modify it even further based on the results of users’ feedback and other changes in the sphere of IT.
Best Practices for Building the Right API
Some of the best practices one must follow for API development are as follows:
1. Use Throttling
App Throttling is something that could be considered to be used for redirecting the extra amount of traffic, having backup APIs, and shielding from DoS attacks.
2. Consider your API gateway as an Enforcer.
Any action that implies the utilization of throttling rules or the application of the API key or OAuth has to have the API gateway as the point of enforcement. This should be understood as a cop, meaning that only the right users can access the data. It should allow you to encrypt the message or modify the data that should not be shared, understanding how your API is being used.
3. Allow overriding HTTP Methods.
Since some proxies only allow GET and POST methods, you have to allow your RESTful API to override the HTTP method. To this end, employ a custom HTTP header named X-HTTP-Method-Override.
4. Evaluate the APIs and Infrastructure
In the current time, real-time analysis is possible, but what if the API server is suspected of having memory leaks, CPU consumption, or other related issues? To consider such scenarios, one has to keep a developer on call. However, you can do this quite easily with the help of numerous tools that can be found in the market, including AWS Cloudwatch.
5. Ensure security
The API technology you use must be secure to the maximum level possible but at the same time, not complicate the process. If a user spends more than five minutes in the authentication process, then anyone can easily conclude that your API is not easy to use. Token-based authentication is one of the ways of protecting your API.
6. Documentation
It is rather beneficial to generate a large amount of documentation for an API for mobile applications. This allows other mobile app developers to easily follow the process and use the information provided to provide a better experience for the users. In other words, good documentation in the API development process will decrease the time to implement project costs, and the efficiency of API technology will be improved.
Average API Development Cost
Data received show that it would cost $20,000 on average to design a comparatively simple API. This number assumes that you are developing a secure, documented, full-featured API with the help of an experienced API software developer in an API development company.
Conclusion
API development is one of the key elements in creating a stable, efficient, and integrated system of software. APIs should be developed based on the business needs, enhance the application, and introduce new business opportunities. Of course, never forget that API success is centered on the target market, the right tools, and the continual analysis and improvement of the API.
FAQs
- What are REST API development and SOAP API?
REST (Representational State Transfer) API entails establishing APIs that utilize HTTP requests to acquire, modify, add, and delete data.
SOAP (Simple Object Access Protocol) API, on the other hand, is a protocol that employs XML to exchange structured data. SOAP APIs are relatively more formal and standard-based than the others and are generally used in enterprise applications where standard compliance is mandatory.
- What is API in software development?
REST API development involves developing APIs that comply with the REST architectural style. HTTP is used as a communication protocol that provides stateless interactions.
- What is the difference between API and Web services?
While often used interchangeably, there is a subtle difference between APIs and Web services:
- All Web services are APIs, but APIs are not always Web services.
- Web services are defined, more particularly, as a manner of exchanging information via a network employing web protocols such as HTTP.
- APIs can be of any kind, such as OS APIs, application APIs, or library APIs, and they can be interpreted in any way possible.
- What is JSON API?
JSON API is a format for building APIs, and this format uses JSON. It prescribes how clients should ask for data and how servers should provide it.
- How do you calculate your API development costs?
API development costs can be estimated based on the level of API, the type of tools/technology required, and the development time.
