Know basic application requests; no coding experience needed.
JSON objects, properties, and values
JSON represents structured data using objects, arrays, strings, numbers, booleans and null. Object keys and string values use double quotes. An array is an ordered list. The value true is a boolean; "true" is text. Standard JSON does not allow comments or trailing commas.
{"hostname":"R1","interfaces":[{"name":"Gi0/0","up":true}]}Sample data · edit it to explore the structure.
This example has a hostname and a list containing one interface. Parsing JSON checks its syntax. It does not prove the device exists or the reported state is accurate. A schema or application rule can check expected fields and types.
REST API requests and responses
An API is an interface used by software. REST-style APIs commonly use HTTP methods: GET reads a resource, POST submits data for processing or creation, PUT replaces a representation, PATCH applies a partial change and DELETE requests removal. The API’s documented contract determines the exact behaviour.
HTTP status codes indicate outcomes: 2xx success, 4xx client-side request problems and 5xx server-side failures. Authentication may use tokens or other mechanisms. Use HTTPS and protect credentials. The browser exercise here parses local sample data; it does not contact or reconfigure a router.
Practical exercise
Read the sample JSON. What is the type of interfaces, and what is the type of the value of up? Then use the practice tool to change up to false.
Show the answer and explanation
interfaces is an array. up is a boolean. Changing true to false is valid JSON; writing False with a capital F is not.
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Technical references checked on 25 October 2026. These are original teaching explanations, not official Cisco course material. See how content and lab validation are described.
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