200-901 Understanding and Using APIs Practice Question
When using RESTCONF to configure a network device, which URL path prefix and content-type header should be used?
⚠ Common exam trap
200-901 often tests the exact RESTCONF media type; candidates pick 'application/json' because it looks familiar, but YANG data requires the '+json' suffix to be accepted by the device.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
/restconf/data/ and Content-Type: application/yang-data+json
RESTCONF uses the '/restconf/data/' path prefix to access configuration and state data modeled in YANG, and the standard media type for JSON-encoded YANG data is 'application/yang-data+json'. The '+json' suffix is required by RFC 8040 to distinguish YANG data from generic JSON. Using '/restconf/operations/' is for invoking RPCs, not for data configuration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
/restconf/operations/ and Content-Type: application/xml
Why it's wrong here
'/restconf/operations/' invokes RPC operations rather than configuring data resources, so it cannot set device configuration. XML is a valid RESTCONF media type, making this combination tempting, and it would be correct when triggering an action such as a route lookup instead of editing configuration data.
- ✓
/restconf/data/ and Content-Type: application/yang-data+json
Why this is correct
RESTCONF mandates the `/restconf/data/` prefix to address the datastore, satisfying the stem's URL path requirement. The `application/yang-data+json` media type correctly encodes YANG-modelled payloads in JSON, which RESTCONF requires for configuration bodies. Together they match the RFC 8040 conventions the device expects.
- ✗
/restconf/data/ and Content-Type: application/json
Why it's wrong here
RESTCONF's mandatory media type is `application/yang-data+json`; plain `application/json` is rejected by conforming servers, so the request fails. It tempts because JSON is the usual REST payload, and `application/json` would be right for a generic REST API rather than a YANG-modelled RESTCONF interface.
- ✗
/restconf/ and Content-Type: text/plain
Why it's wrong here
'text/plain' is not a media type RESTCONF accepts for configuration payloads, so the request is rejected regardless of path. The bare '/restconf/' prefix is tempting because it is the API root, but it exposes capability discovery, not configurable data resources.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-901 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 200-901 exam.