What does API stand for?
API stands for application programming interface. In the API environment, the term application refers to any software with unique features. An interface can be seen as a service contract between two applications. The contract defines how the two communicate with each other using requests and responses. Their API documentation includes information about how developers build these requests and responses.
What is the working principle of the API?
The API architecture is usually explained from the perspective of the client and the server.The application that sends the request is called the client, and the application that sends the response is called the server.Taking weather as an example, the weather database of the Meteorological Bureau is the server, while the mobile application is the client.
There are four different ways the API works, depending on when it was created and why it was created.
SOAP API:
These APIs use simple object access protocols.The client and server use XML to exchange messages.This is a less flexible API, which has been more popular in the past.
RPC API:
These APIs are called remote procedure calls.The client completes the function (or procedure) on the server, and the server sends the output back to the client.
Websocket API
The Websocket API is another modern Web API development method that uses JSON objects to pass data.The WebSocket API supports two-way communication between the client application and the server.The server can send callback messages to connected clients, making it more efficient than the REST API.
REST API:
These are the most popular and flexible Web APIs today. The client sends a request to the server in the form of data.The server uses the client input to start executing internal functions and returns the output data to the client. Let’s take a closer look at the REST API.
What is a REST API?
REST represents the state transition of the performance layer. REST defines a set of functions, such as GET, PUT, DELETE, etc., that clients can use to access server data. The client and server use HTTP to exchange data.
The main feature of the REST API is stateless. Stateless means that the server will not save client data between various requests. The client’s request to the server is similar to the URL you type in your browser to access a website. The response from the server is pure data and does not include typical graphical rendering of Web pages.
What is a Web API?
A Web API or Web service API is an application processing interface between a Web server and a Web browser. All Web services are APIs, but not all APIs are Web services. REST API is a special type of Web API, which adopts the standard architecture style described above.
Historically, various terms related to APIs (such as Java APIs or service APIs) have existed because APIs were created before the advent of the World Wide Web. Modern Web APIs are REST APIs, and these terms can be interchanged.
What is API integration?
API integration is a software component that automatically updates data between the client and the server. Some examples of API integration include that when you automatically sync data from your phone’s photo gallery to the cloud, or when you travel to another time zone, the time and date on your laptop will be automatically synchronized. Enterprises can also use APIs to efficiently automate many system functions.
What are the advantages of REST API?
The REST API has four advantages：
1.integration
The API is used to integrate new applications with existing software systems. This can increase development speed because you don’t have to write every feature from scratch. You can use the API to take advantage of existing code.
2.innovation
The emergence of a new application may bring changes to the entire industry.Enterprises need to respond quickly and support the rapid deployment of innovative services.They can do this by making changes at the API level without having to rewrite all the code.
3.extension
APIs can provide companies with unique opportunities to meet customer needs across different platforms.For example, the map API allows the integration of map information through websites, Android, iOS and other platforms.Any enterprise can provide similar internal database access by using free or paid APIs.
4.Easy to maintain
The API acts as a gateway between the two systems. Each system must make internal changes so that the API is not affected. In this way, any future changes made by one party to the code will not affect the other party.
What are the different types of APIs?
APIs are classified according to their architecture and scope of use. We have discussed the main types of API architecture, let’s take a look at its scope of use.
Private API
This kind of API is aimed at the internal enterprise and is only used to connect systems and data within the enterprise.
Public API
This kind of API is open to the public and can be used by anyone.There may be authorization and costs associated with these types of APIs.
Partner API
Only authorized external developers can access these APIs, and these APIs help to establish partnerships between companies.
Composite API
These APIs combine two or more different APIs to meet complex system requirements or handle complex behaviors.
What is an API endpoint and what is its significance?
The API endpoint is the final point of contact in the API communication system. These include server URL, service, and other specific digital locations through which information can be sent and received between systems. API endpoints are essential to enterprises for two main reasons：
1.security
API endpoints make the system vulnerable to attacks.API monitoring is the key to preventing abuse.
2.performance
API endpoints (especially high-traffic endpoints) may cause bottlenecks and affect system performance.
How to protect the REST API?
All APIs must be protected through proper authentication and monitoring. The two main ways to protect the REST API include：
1.Authentication token
These tokens are used to authorize users to make API calls.Authentication tokens can be used to confirm whether the user’s identity is true and whether they have access to that particular API call.For example, if you log in to an email server, the email client uses an authentication token for secure access.
2.API key
The API key verifies the program or application that made the API call.They can identify the application and ensure that the application has the access rights required to make specific API calls.API keys are not as secure as tokens, but API monitoring can be implemented to collect usage data.When you visit different websites, you may notice a long list of characters and numbers in the browser URL.This string is the API key used by the website to make internal API calls.
How to create an API?
To build an API that other developers are willing to use and trust requires due diligence and hard work.Here are the five steps required to design a high-quality API：
1.Planning API
API specifications (such as OpenAPI) can provide blueprints for API design.It is best to consider different usage scenarios in advance and ensure that the API meets existing API development standards.
2.Build API
API designers use boilerplate code for API prototyping.After the prototype passes the test, developers can customize it according to internal specifications.
3.Test API
API testing is the same as software testing, and testing must be carried out to prevent errors and defects.API testing tools can be used to further test the API’s ability to respond to network attacks.
4.Write API documentation
Although the API is self-explanatory, the API documentation can serve as a guide to improving availability.Well-documented APIs can provide a range of functions and usage scenarios, and are often more popular in service-oriented architectures.
5.Bringing APIs to market
Amazon is an online market in the retail sector, while the API market provides developers with a platform to buy and sell other APIs. List your API in order to monetize it.
What is API testing?
The API testing strategy is similar to other software testing methods. The focus is on verifying the server response. API testing includes：
Make multiple requests to the API endpoint for performance testing.
Write unit tests to check the correctness of business logic and functions.
Conduct security tests by simulating system attacks.
How to write API documentation?
Writing comprehensive API documentation is part of the API management process.API documents can be automatically generated using tools or written manually.Some of the best practices include：
Write instructions in simple and easy-to-understand English expressions.The documents generated by the tool may be lengthy and need to be edited.
Use code examples to illustrate the function.
Maintain documents to make them accurate and up-to-date.
Novices should be fully considered when writing documents
Explain all the problems that the API can solve for users.
How to use the API?
The steps to implement the new API include：
Get the API key.This can be achieved by creating a verified account with the API provider.
Set up the HTTP API client.This tool allows you to easily construct API requests using the received API key.
If you don’t have an API client, you can refer to the API documentation and try to build the request in the browser yourself.
Once you are familiar with the new API syntax, you can start using it in your code.
Where can I find the new API?
New Web APIs can be found in the API market and API catalog.The API market is an open platform where anyone can put APIs on the shelves to sell.The API directory is a controlled repository supervised by the directory owner.Professional API designers may evaluate and test new APIs before adding them to their catalog.
Some popular API websites include：
Rapid API–the world’s largest API market, with more than 10,000 public APIs and 1 million active online developers.RapidAPI allows users to test the API directly on the platform before purchasing.
Public APIs–The platform divides remote APIs into 40 subdivided categories, making it easier for you to browse and find relevant APIs that meet your needs.
APIForThat and APIList–These two websites provide a list of more than 500 Web APIs and provide an in-depth introduction to how to use these APIS.
What is API Gateway?
API Gateway is an API management tool suitable for enterprise clients using various back-end services.API Gateway is usually used to handle common tasks that apply to all API calls, such as user authentication, statistics, and rate management.
Amazon API Gateway is a fully managed service that helps developers easily create, publish, maintain, monitor, and protect APIs of any size.It is responsible for managing all tasks, involving accepting and processing thousands of concurrent API calls, including traffic management, CORS support, authorization and access control, throttling, monitoring, and API version management.
What is GraphQL?
GraphQL is a query language developed specifically for APIs.It is only to give priority to the client to provide the exact data requested.It is designed to improve API speed and flexibility, and to be easy for developers to use.As an alternative to REST, GraphQL provides front-end developers with the ability to query multiple databases, microservices, and APIs through a single GraphQL endpoint. Companies choose to use GraphQL to build APIs because it helps speed up application development. Learn more about GraphQL here.
AWS AppSync is a fully managed service that develops GraphQL APIs by handling heavy and secure connection tasks with data sources such as AWS DynamoDB and AWS Lambda, and AWS AppSync can push real-time data updates to millions of clients through Websocket. Update.For mobile and Web applications, AppSync can also provide local data access when the device is offline.After deployment, AWS AppSync will automatically scale up and down the GraphQL API execution engine to meet the API request volume requirements.
