![\"Developer](\"https:\/\/ccbill.com\/kb\/wp-content\/uploads\/2022\/07\/api-types.png\")
<\/figure><\/div>\n\n\nWhat is an API?<\/h2>\n\n\n\n
An API<\/a> (Application Programming Interface) is a set of protocols and declarations that allow a software solution to interact with and provide services to other software. API is the medium for translating data from one program so that another program can read it.<\/p>\n\n\n\n Organizations use APIs to expose a software product, its capabilities, and data in a machine-readable format. Internal and external clients utilize these resources to build new products and deliver value to the end customer.<\/p>\n\n\n\n For example, a PSP (Payment Service Provider) discloses API endpoints<\/a> (digital locations) for payment authentication<\/a> and processing services. Merchants do not need to understand the remote system\u2019s source code; they only need instructions on how to connect their solution to the API endpoint (i.e., integrate with the API<\/a>).<\/p>\n\n\n\n Note<\/strong>: Find out how to use CCBill\u2019s API to streamline and automate payment flows in your online store. CCBill\u2019s RESTful Transaction API<\/a> documentation explains how to charge customers using payment tokens.<\/p>\n\n\n\n A company can utilize different APIs to create unique business solutions and customer-facing applications. Based on the release policy and scope of use, there are four types of APIs.<\/p>\n\n\n\n A public API, sometimes called an open or external API, is intended to be consumed by as many clients as possible. Third-party developers can freely access API documentation and use it to develop and test applications without licensing restrictions. <\/p>\n\n\n\n Organizations openly share their system\u2019s functionalities and data to increase brand awareness or as part of a market penetration strategy.<\/p>\n\n\n\n Companies use internal APIs to integrate existing applications and systems or build new apps that streamline business processes. They remain in complete control over the API's usage and prevent individuals or applications outside the organization from accessing or communicating with internal systems.<\/p>\n\n\n\n Even though internal APIs are only used within an organization, developers should not compromise on security features, user authorization, or authentication. Companies dealing with sensitive customer information, like payment card data, must ensure that their internal APIs comply with the PCI Data Security Standard<\/a>.<\/p>\n\n\n\n Some organizations provide API access to their applications and databases<\/a> to other companies (partners) to increase ancillary revenue. <\/p>\n\n\n\n A partner API is often used to share sensitive customer information with known business partners, and it incorporates advanced security features and strong user authentication<\/a> mechanisms.<\/p>\n\n\n Partnering companies enter into an agreement with clearly defined API usage terms, costs, and licenses. API providers want to ensure that access is not used in a way that can damage their reputation.<\/p>\n\n\n\n A complex action like creating a shopping cart order requires several API calls<\/a> sent to multiple API endpoints. <\/p>\n\n\n\n Composite APIs allow developers to batch several API requests into a single API call and receive a single response in return. Composite APIs are ideal for users who need to collect data from multiple sources and perform a particular task. By reducing the number of API requests and responses, composite APIs can improve application loading times and performance.<\/p>\n\n\n\n Note: <\/strong>Read our article to learn more about API integration<\/a> and how it can help streamline workflows.<\/p>\n\n\n\n Developers use different technologies and programming languages when developing applications and web services. An API needs to offer a common structure with clear rules and constraints to enable clear communication between two different software solutions.<\/p>\n\n\n\n The four widely used API development protocols or architecture styles include:<\/p>\n\n\n\n Each format has unique advantages and drawbacks depending on specific use cases and business objectives.<\/p>\n\n\n\n The REST (representational state transfer) architecture style is popular for building APIs consumed by web servers and web apps<\/a>.<\/p>\n\n\n\n REST relies on a client\/server architecture, enabling developers to separate front-end and back-end services. This allows different components to evolve independently over time without compromising system stability.<\/p>\n\n\n\n REST APIs<\/a> are stateless as receivers cannot keep the session state from a prior request. No information from a call is retained, meaning each session is independent and is understood in isolation.<\/p>\n\n\n\n Web APIs that adhere to REST constraints are called RESTful APIs. RESTful APIs use HTTP requests (methods) and URL-encoded parameters to access API resources. Commonly used RESTful HTTP methods include: <\/p>\n\n\n\n RESTful supports many different formats for exchanging and storing data:<\/p>\n\n\n\n An example of an API request for creating a payment token using CCBill's RESTful API:<\/p>\n\n\n\n REST is a flexible and scalable architecture style that can support large and dynamic customer bases, making it ideal for public APIs.<\/p>\n\n\n\n The Remote Procedural Call (RPC) involves sending a request to a remote server and receiving a structured response. RPC is used to initiate actions, unlike REST API, which is used to exchange documents (resources).<\/p>\n\n\n\n RPC APIs are highly structured, and developers can use either JSON or XML to encode requests and bind resources to specific purposes and functions.<\/p>\n\n\n RPC APIs are not well suited for intense public consumption. RPC API is best implemented in a microservices-oriented system, where it results in a more tightly coupled and efficient environment.<\/p>\n\n\n\n SOAP (Simple Access Object Protocol) is a messaging standard that supports HTTP, TCP, and SMTP communication protocols. Most operating systems utilize these protocols, allowing SOAP-based APIs to power web services regardless of the underlying programing language or platform.<\/p>\n\n\n\n SOAP has a strict structure, and developers are required to encode SOAP messages as XML documents. SOAP messages<\/a> contain up to four elements:<\/p>\n\n\n\n
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\n\n\n\nAPI Types<\/h2>\n\n\n\n
Public APIs<\/h3>\n\n\n\n
Internal APIs<\/h3>\n\n\n\n
Partner APIs<\/h3>\n\n\n\n
![\"Using](\"https:\/\/ccbill.com\/kb\/wp-content\/uploads\/2022\/07\/api-type-user-app.png\")
<\/figure><\/div>\n\n\nComposite APIs<\/h3>\n\n\n\n
\n\n\n\n
\n\n\n\nAPI Architectural Styles (Protocols)<\/h2>\n\n\n\n
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REST<\/h3>\n\n\n\n
\n
\n
var data = JSON.stringify({\n "clientAccnum": 900000,\n "clientSubacc": 0,\n "customerInfo": {\n "customerFname": "Tyler",\n "customerLname": "Thomas",\n "address1": "Woodland Drive",\n "address2": "Apt 21",\n "city": "Tempe",\n "state": "AZ",\n "zipcode": "85281",\n "country": "US",\n "phoneNumber": "5555555555",\n "email": "tthomas@xyz.com",\n "ipAddress": "10.70.60.14'",\n "browserHttpUserAgent": "Mozilla\/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko\/20100101 Firefox\/60.0",\n "browserHttpAccept": "text\/html,application\/xhtml+xml,application\/xml;q=0.9,*\/*;q=0.8",\n "browserHttpAcceptLanguage": "en-US,en;q=0.5",\n "browserHttpAcceptEncoding": "gzip, deflate, br"\n },\n "paymentInfo": {\n "creditCardPaymentInfo": {\n "cardNum": "4473707989493598",\n "nameOnCard": "Tyler Thomas",\n "expMonth": "04",\n "expYear": "2019"\n }\n },\n "subscriptionId": 900000000000000000,\n "timeToLive": 30,\n "validNumberOfUse": 3\n});\n\nvar xhr = new XMLHttpRequest();\nxhr.withCredentials = true;\n\nxhr.addEventListener("readystatechange", function () {\n if (this.readyState === 4) {\n console.log(this.responseText);\n }\n});\n\nxhr.open("POST", "https:\/\/api.ccbill.com\/payment-tokens\/merchant-only");\nxhr.setRequestHeader("Content-Type", "application\/json");\nxhr.setRequestHeader("Authorization", "Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.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.HRYXZFATkIcI2_LJ1W_xo67IfBnbN9atyYNzyHqseLxYUxzgwBsAV5rNqCixKemOrDIeQLBN4jrwRsBIHDpEvshwBC8XmTodDJzpGmMaU9s1r20RV68X0_d1yTgSDke_Of7VCrVmJRbSuDl7AgsfTqQ1J7nWyu9vcIaER93ms-vadser_Ot9Z68_HAmCJL3DCLpdIFq3PYtBMKKKqXbvhfhSZQZD3b6-aewAnBo0VzpvK6tREqw1rv9_73oAvYcW2aHAj79ILr8viWMM40LyDKMMYOYkneg3hJUQsUVeh9WzztYUJKzERYNXje9fYIGN-eofoLvX7OZJ3eXmIfkrfQ");\nxhr.setRequestHeader("Cache-Control", "no-cache");\n\nxhr.send(data);<\/code><\/pre>\n\n\n\nRPC<\/h3>\n\n\n\n
![\"A](\"https:\/\/ccbill.com\/kb\/wp-content\/uploads\/2022\/07\/rpc-api-type.png\")
<\/figure><\/div>\n\n\nSOAP<\/h3>\n\n\n\n