Essential API Terminology for Software Professionals

APIs are everywhere, and so is the need for solid API testing skills. But all the jargon can be confusing. This glossary unpacks essential API terminology, making even complex API terms crystal clear. Whether you're a developer, tester, or just curious about APIs, this API testing glossary is your guide. We'll cover everything from basic API calls to advanced concepts, giving you the confidence to work with APIs effectively. This API glossary is your key to success in the world of software development.

Despite this trend, not everyone gets the opportunity to work with APIs. Few organizations are focused on front-end automation. But as a Tester, we should be versatile, right? There are a lot of materials available online to get started. But, of course, finding the right one is always challenging. 

How do we start this journey? How can we help you? 

We created an API testing glossary that defines the technical jargon used in API Testing. This covers some basic API terms as well. 

Keep in mind the basics are a must. They help you to build stronger APIs. So why wait? Let’s get started.

Essential API Testing Terms You Need to Know

API: Application Programming Interface, a set of functions that allows an application to interact with external applications, operating systems, microservices, or data.

API-First: A development approach that considers application programming interfaces (APIs) before anything else. It ensures that all of the platform/application functionalities are accessible through the APIs.

API Testing: Checking whether the API meets expectations in terms of functionality, reliability, performance, and security.

API Orchestration: The unification/merging of different APIs into a single front-end. It is now a central component of creating and designing enterprise workflows. API orchestration layer is an abstraction layer that collects data from one or more services and prepares them in favor of client applications.

API Version: Similar to document versioning, API versioning tracks changes in the API. Proper versioning supports maintenance and tracking. A new API version is created when major changes to the endpoints/payload are made.

API Gateway: A single entry point for all clients. It helps balance the load to the endpoints received from different clients. It also helps in handling the API traffic. 

API Security: Focused strategies that protect APIs from attacks. Any security breach will lead to data leakage and become a serious threat.

API Design: Developing the APIs as per the business process and requirements. This serves as a single source of truth for the API. Good API design helps to minimize the problems. The Design-First approach helps in developing stable APIs that meet expectations. 

API Deprecation: In some situations, the API is deprecated (no longer used). Various factors contribute to the deprecation of the APIs: project requirement changes, insecure APIs, inefficiency, or replacement, to name a few. 

API Keys: The unique code used for authentication of the API. One of the authorization methods to access the API. Some APIs use the keys in the params, and some use them in the headers. 

API Request: API request is the set of details needed to submit to the server to understand and respond properly. 

API Response: After sending the details as a request, the server interprets and sends the response back to the client. 

API Virtualization: API Virtualization is the process of mirroring your production APIs that promotes testing efficiency. It helps to test the team with realistic test data.

API Documentation: The complete set of technical information and capabilities of the API. It carries all the sufficient information to work with that API. 

BaseURI: Base Uniform Resource Identifier is the complete path used to locate a specific resource (Base URL, which is the application URL + path)

Contract: An agreement details what the consumer can expect from the API. It details how the API works. It is the same as API documentation. 

Content API: These APIs provide or transfer the contents. Not just a mere communication mode, it also helps to retrieve or collect important content.

CORS:  Cross-Origin Resource Sharing (CORS) is an HTTP-header-based mechanism that allows a server to indicate any origins (domain, scheme, or port) other than its own from which a browser should permit loading resources. Additional HTTP headers are used to instruct the browsers. 

cURL (Client URL): a cURL is a command-line tool for transferring data from or to a server designed to work without user interaction. cURL helps get information from APIs, download web pages, or submit data to an API.

Composite APIs: Composite APIs are the combined APIs that help us access several endpoints through a single API call.

GraphQL: GraphQL is an application-level query language and runtime for APIs. It is a more efficient, flexible, and powerful way of working with APIs when compared to REST. 

gRPC (Google Remote Procedure Call): A modern open-source RPC architecture framework designed by Google that can run in any environment. It is robust, scalable, and fast.

HTTP methods: An HTTP (HyperText Transfer Protocol) request is an action to be performed on a resource identified by a given Request-URL. Request methods are case-sensitive. The most common ones are: GET, POST, PUT, and DELETE.

HTTP Headers: Headers are the additional but essential information sent as part of the request details from the client for the server to understand the client. 

JSON (JavaScript Object Notation): JSON is an open-standard file format or data interchange format in a human-readable style. It is language-independent and represents the data using a key/value pair.

Karate DSL: A framework for API automation testing, running on Java and using Apache HTTP client to perform HTTP connections. It can be integrated with the Gatling framework for performance testing.

Microservices: A modular software component that does one defined job. It is an architectural style that structures an application as a collection of small autonomous services modeled around a business domain. They are small, independent, and loosely coupled. 

Mock Servers: In some situations, the mock server behaves like a real server, but it responds with the same set of responses as mocked. It emulates the real server.

MQTT (Message Queuing Telemetry Transport): MQTT is the most commonly used messaging protocol for the Internet of Things (IoT). MQTT allows for messaging between devices to the cloud and the cloud to the device. 

OpenAPI: OpenAPI is a specification that describes, produces, consumes, and visualizes RESTful APIs and web services.

OAuth: OAuth is a delegated authorization framework used for REST/APIs. This is one of the efficient methods of authorizing, which restricts the improper usage of the APIs. For example, a user can sign in on one platform and then be authorized to perform actions and view data on another platform with OAuth.

OWASP (Open Web Application Security Project): A non-profit organization dedicated to improving web application security. All of its resources are free of charge.

Pagination of APIs: The pagination mechanism is used when the API returns a large data set. It is similar to how the Google search response is handled and split into pages. There are different types of Pagination:

• Offset Pagination: is the simplest method; “limit” and “offset” values are used here.
• Keyset Pagination: uses the filter values of the previous page to determine the next set of items.
• Seek Pagination: this is the enhanced version of keyset pagination. It helps filter the particular limit. 

Parameters: API Parameters are passed along with the endpoint URL, which helps filter resources. Path/Query params are the most frequently used ones.

Public APIs: An open or public API saves developers time by allowing them to connect their platform with previously existing tools, reducing the need to create entirely new functions. Most public APIs require no authorization.

Private APIs: Internal APIs are the opposite of open APIs in that they are inaccessible to external consumers and only available to an organization’s internal developers. Internal APIs can enable enterprise-wide initiatives from adopting DevOps and microservice architectures to legacy modernization and digital transformation. 

Payload: The actual body/content passed as part of the API request. It can be in different forms such as JSON, Text, HTML, XML, etc. 

Postman: Postman is a platform to build, test, design, modify, and document APIs. It is a simple Graphic User Interface for sending and viewing HTTP requests and responses.

RAML (RESTful API Modeling Language): RAML is a powerful YAML-based language used to define API contracts. RAML allows teams to define, build and collaborate on APIs rapidly and easily.

RapidQL: RapidQL is a JSON-like query language implemented in JavaScript. This essentially helps describe the various inputs used in your queries. 

REST (REpresentational State Transfer): REST is a software architectural style that defines a set of methods to build a web Application Programming Interface (API). REST is one of the most popular types of API due to its simplicity and client-friendly nature. Requests are sent via several formats: JSON, HTML, XML, plain text. JSON is the most commonly used format.

Rest Assured: REST Assured is a Java library used for testing and validating the REST APIs.

Schema: It defines the data format, including the data types. This schema validates the API requests. 

SOAP (Simple Object Access Protocol): SOAP is an XML-based protocol for accessing web services over HTTP. The SOAP message is nothing but an XML document with an envelope, header, and body.

Status Codes: The list of numeric codes followed by a message returned from the server to the client. Each response code tells a different story about the API response. 

SSL Certificates: SSL certificates create a foundation of trust by establishing a secure connection. It is a small data file that cryptographically establishes an encrypted link between a web server and a browser. It protects client-server communication from vulnerable attacks. 

Swagger: Swagger is an open-source set of rules, specifications, and tools for developing and describing RESTful APIs. Also, there is an open-source tool called Swagger, which is used to design, build, document, and use RESTful web services. 

YAML (Yet Another Markup Language): YAML is a data serialization format similar to XML and JSON. YAML is a case-sensitive, human-readable data format.

Webhook APIs: A webhook is a lightweight API that powers one-way data sharing triggered by events. Webhooks are also called reverse APIs. They help send messages, alerts, and notifications from the server to the client.

Web Scraping: Web scraping or web data extraction is data scraping used for extracting data from websites. The wanted content is segregated and separated from the list of long content. 

WebSockets: A WebSocket is a transport protocol defined by a persistent bi-directional communication channel between a client and the server. It was designed to overcome the limitations of HTTP’s basic request/response mechanism.

The list is huge, right? Still, they will be helpful to you. Once you understand this technical jargon, you can connect the dots during your API testing journey.

Happy API days!

Key Takeaways

• Mastering API terminology is fundamental for effective communication and collaboration. A shared understanding of terms like endpoints, HTTP methods, and status codes streamlines development and testing processes.
• A well-designed and thoroughly tested API is key to a successful application. Prioritizing API design and incorporating comprehensive testing from the start ensures reliability and reduces future issues.
• Protecting your API requires a multi-layered security approach. Implementing robust authentication, authorization, and access control mechanisms safeguards your data and prevents unauthorized access.

Core API Concepts

API Call (Request)

An API request is simply a set of instructions you send to a server. Think of it like ordering food at a restaurant—your order is the request, specifying what you want. This request includes details like the specific data you're asking for and the action you want the server to perform.

API Endpoint

The API endpoint is the specific location where you send your request. Using the restaurant analogy, it's like the kitchen door where your order goes. It's a specific URL that represents a resource or a function on the server.

HTTP Methods (GET, POST, PUT, PATCH, DELETE)

HTTP methods define the kind of action you want to perform. Common methods include GET (retrieve data), POST (send new data), PUT (update existing data), PATCH (partially update data), and DELETE (remove data). These methods provide a standardized way to interact with resources on the server.

Status Codes

After sending a request, the server sends back a status code. These codes indicate whether your request was successful (e.g., 200 OK) or if there was an issue (e.g., 404 Not Found). Understanding these codes helps you troubleshoot and debug your API interactions.

Data Formats (JSON, XML)

Data is typically exchanged in specific formats like JSON or XML. JSON is more common due to its readability and efficiency, making it easier for both humans and machines to parse and understand the data being exchanged.

CRUD Operations

CRUD stands for Create, Read, Update, and Delete. These are the fundamental operations you can perform on data through an API. Most APIs provide endpoints for performing these CRUD operations on the resources they manage.

API Architectures

Different API architectures exist, such as REST, SOAP, and GraphQL. Each has its own set of principles and benefits. Choosing the right architecture depends on the specific needs of your application and the complexity of the data being exchanged.

API Development Processes

API-First Development

API-first development prioritizes designing the API before building the application. This ensures a well-structured and consistent API, making it easier to integrate with other systems and reducing development time in the long run.

API Testing (Including Shift-Left Testing)

Thorough API testing is crucial for ensuring quality and reliability. Shift-left testing involves testing early and often in the development cycle, catching bugs sooner and reducing the cost of fixing them later. Comprehensive testing, like that offered by MuukTest, can significantly improve the reliability of your APIs.

API Mocking

API mocking involves creating simulated APIs for testing purposes, especially useful when the actual API isn't yet available. This allows developers and testers to continue their work without being blocked by dependencies.

API Collaboration

Effective API collaboration between developers and testers is essential for building robust and well-documented APIs. Clear communication and shared understanding of the API's functionality are key to successful collaboration.

API Security and Access

API Authentication

API authentication verifies the identity of the client making the request, often using API keys or tokens. This ensures that only authorized clients can access your API.

API Authorization

API authorization determines what actions an authenticated client is allowed to perform. This prevents unauthorized access to sensitive data or functionalities.

API Access Control

API access control involves implementing policies and mechanisms to restrict access to API resources and prevent unauthorized use. This adds another layer of security to your API, protecting it from potential threats.

CORS (Cross-Origin Resource Sharing)

CORS is a security mechanism that allows or restricts web pages from making requests to a different domain. This helps prevent malicious websites from accessing your API without permission.

API Tools and Platforms

API Clients

API clients like Postman simplify interacting with APIs, allowing you to send requests and view responses easily. These tools streamline the testing and debugging process.

API Gateways

API gateways act as a central point of entry for all API requests, managing traffic and enforcing security policies. They help improve performance and security by centralizing API management.

API Marketplaces

API marketplaces provide a platform for discovering and accessing publicly available APIs. This allows developers to easily integrate third-party services into their applications.

API Portals

API portals offer comprehensive documentation and resources for developers working with specific APIs. Good documentation is essential for understanding how to use an API effectively.

General API Information

API Economy

The API economy refers to the business ecosystem built around APIs, where companies leverage APIs to create new revenue streams and partnerships. APIs have become a crucial part of modern business, enabling integration and collaboration between different organizations.

API Lifecycle

The API lifecycle encompasses all stages of an API's existence, from design and development to deployment and retirement. Understanding the lifecycle helps manage APIs effectively throughout their lifespan.

Importance of Well-Designed APIs

Well-designed APIs are essential for usability, maintainability, and scalability. Good design minimizes integration issues and promotes wider adoption. Investing in good API design pays off in the long run by reducing development costs and improving the overall quality of your software.

API Fuzz Testing

API fuzz testing is a security testing technique that involves sending random or invalid input to an API to identify vulnerabilities. This helps uncover potential security flaws before they can be exploited by attackers.

Layered System

A layered system architecture promotes modularity and separation of concerns, making APIs easier to manage and update. This approach improves flexibility and maintainability.

Client-Server Architecture

Client-server architecture is the foundation of most APIs, where clients request services from a server. This fundamental concept underlies how APIs function.

Cacheability

Cacheability refers to the ability to store and reuse API responses, improving performance and reducing server load. Caching can significantly improve the responsiveness of your application.

Uniform Interface

A uniform interface simplifies interaction with an API by providing a consistent set of rules and conventions. This makes it easier for developers to understand and use your API.

Statelessness

Statelessness in APIs means that each request is treated independently, without relying on previous interactions. This improves scalability and reliability, as the server doesn't need to maintain state information between requests.

Related Articles

• API Terminology: The Ultimate Guide for Beginners
• The API Testing Glossary: Key Terms and Definitions
• API Testing Essentials
• REST API Testing: The Complete Guide
• API Automation Testing: Benefits, Challenges & Best Practices

Frequently Asked Questions

Why is API testing so important?

API testing is crucial because APIs serve as the backbone for many applications, connecting different systems and enabling communication. Testing ensures that these connections are reliable, secure, and perform as expected. A well-tested API leads to a more stable and robust application overall.

What are some common challenges in API testing?

Common challenges include ensuring comprehensive test coverage, managing different data formats, handling authentication and authorization, and keeping up with evolving API designs. Tools like MuukTest can help overcome these challenges by automating the testing process and providing comprehensive test coverage.

How can I get started with API testing?

Start by familiarizing yourself with basic API concepts like requests, endpoints, and HTTP methods. Then, explore different API testing tools like Postman or Rest Assured. There are many online resources and tutorials available to guide you through the process. Hands-on practice is key to mastering API testing.

What is the difference between REST and SOAP APIs?

REST (Representational State Transfer) and SOAP (Simple Object Access Protocol) are two different architectural styles for building APIs. REST is generally preferred for its simplicity and flexibility, using standard HTTP methods and lightweight data formats like JSON. SOAP is more complex, relying on XML and often requiring more overhead.

How does MuukTest help with API testing?

MuukTest offers AI-powered test automation services that can significantly enhance your API testing efforts. They provide comprehensive test coverage, integrate with CI/CD workflows, and offer scalable solutions tailored to your specific needs. Their expertise can help you achieve complete test coverage efficiently and cost-effectively, ensuring the quality and reliability of your APIs.