Which term refers to a lightweight data-interchange format that is easy for humans to read and write, and easy for machines to parse and generate?
Drag a concept onto its matching description — or click a concept then click the description.
Lightweight structured data format often used in API responses
Data modeling language for network configuration and state
Architecture style that commonly uses HTTP methods such as GET and POST
Credential or value used to authorize API requests
⚠ Common exam trap
The trap is confusing data formats with API protocols. Many candidates mistakenly think XML or JSON are protocols because they are used with REST/SOAP, but they are formats. Remember: formats describe data structure; protocols define communication rules.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
JSON
JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is commonly used in REST APIs. XML (eXtensible Markup Language) is also a data format but it is more verbose and uses tags; it is typically associated with SOAP rather than being the best match for the description given. REST (Representational State Transfer) is an architectural style, not a data format, and SOAP (Simple Object Access Protocol) is a protocol, not a data format. Therefore, only JSON correctly matches the description of a lightweight data format.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
JSON
Why this is correct
JSON (JavaScript Object Notation) is a lightweight, language-independent data-interchange format that represents structured data as key-value pairs and ordered lists. It is human-readable and machine-parseable, making it the default payload format for modern REST APIs. Unlike protocols such as REST or SOAP, JSON is purely a data format with no transport or messaging semantics.
XML
Why it's wrong here
XML (eXtensible Markup Language) is a verbose, tree-structured data format that uses custom tags to define elements, with support for namespaces and schemas (XSD) to enforce data validation. While it can carry data in APIs, it is not an API protocol itself. Compared to JSON, XML is more heavyweight and harder for humans to read, yet it excels in document-centric use cases where metadata and extensibility are critical.
When this WOULD be correct
If the question asked 'Which data format uses tags like <name>value</name>?' or 'Which format is commonly used in SOAP web services?', then XML would be correct.
REST
Why it's wrong here
REST (Representational State Transfer) is an architectural style for designing distributed systems, not a data format. It leverages standard HTTP methods like GET, POST, PUT, and DELETE to manipulate resources identified by URLs, typically exchanging data in JSON or XML. Because REST dictates how clients and servers interact rather than how data is serialized, it belongs in the API protocol/architecture category.
When this WOULD be correct
REST would be correct in a question asking to match API architectural styles to their characteristics, such as 'Which API style uses standard HTTP methods and is stateless?'
SOAP
Why it's wrong here
SOAP (Simple Object Access Protocol) is a strict, standards-driven messaging protocol that encodes its messages exclusively as XML, often relying on WSDL and UDDI for service description and discovery. It is not a data format but a wire protocol that defines envelope, header, and body structures, along with rules for error handling and security. SOAP's rigid structure and overhead make it heavier than REST-based web services.
When this WOULD be correct
In a question asking to match API protocols to their characteristics, SOAP would be correct for 'uses XML-based messaging' or 'supports WS-Security'. For example, 'Match each API protocol to its primary messaging format: SOAP → XML'.
Option-by-option analysis
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
Why this is correct
JSON (JavaScript Object Notation) is a lightweight, language-independent data-interchange format that represents structured data as key-value pairs and ordered lists. It is human-readable and machine-parseable, making it the default payload format for modern REST APIs. Unlike protocols such as REST or SOAP, JSON is purely a data format with no transport or messaging semantics.
Why this is wrong here
XML is a data format, but the question asks for the best description of JSON. XML is more verbose and less commonly used in modern APIs compared to JSON.
★ When this WOULD be the correct answer
If the question asked 'Which data format uses tags like <name>value</name>?' or 'Which format is commonly used in SOAP web services?', then XML would be correct.
Why candidates choose this
Candidates may confuse XML with JSON as both are data interchange formats, or they might think XML is more 'standard' and thus the correct answer.
Why this is wrong here
The question asks to match data format or API terms to descriptions, and REST is an architectural style for designing networked applications, not a data format or API term like JSON, XML, or SOAP.
★ When this WOULD be the correct answer
REST would be correct in a question asking to match API architectural styles to their characteristics, such as 'Which API style uses standard HTTP methods and is stateless?'
Why candidates choose this
Candidates often confuse REST with a data format because it is commonly used with JSON in web APIs, leading them to think it is a data format itself.
Why this is wrong here
SOAP is a protocol for exchanging structured information, not a data format like JSON. The question asks for a data format or API term, and SOAP is an API protocol, but it is not a data format; JSON is the correct data format match.
★ When this WOULD be the correct answer
In a question asking to match API protocols to their characteristics, SOAP would be correct for 'uses XML-based messaging' or 'supports WS-Security'. For example, 'Match each API protocol to its primary messaging format: SOAP → XML'.
Why candidates choose this
Candidates may confuse SOAP with a data format because it uses XML, or they might think 'API term' includes SOAP as a valid option, overlooking that JSON is the only data format listed.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
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Agentic AI in Network Operations
Key term
XML
XML is a flexible text format used to store and transport data in a way that both humans and computers can read, using custom tags to describe the data's structure.
Key term
JSON
JSON is a lightweight, text-based format for storing and exchanging data that is easy for humans to read and write and easy for machines to parse and generate.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.