200-901 Understanding and Using APIs Practice Question
This 200-901 practice question tests your understanding of understanding and using apis. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer is troubleshooting an API call to Cisco SD-WAN vManage. The request fails with HTTP 400 status and the response body: '{"error": "Bad Request", "details": "Invalid JSON: unexpected token at position 42"}'. Which tool or technique should the developer use to quickly identify the syntax error?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use a JSON validator to check the request body.
The HTTP 400 status code indicates a client-side error, and the response body explicitly states 'Invalid JSON: unexpected token at position 42'. This means the request body contains malformed JSON. A JSON validator (e.g., jsonlint.com, jq, or a library like `json.loads()` in Python) will parse the JSON and pinpoint the exact syntax error (e.g., a missing comma, extra brace, or unescaped quote) at the specified position, allowing the developer to fix the request body quickly.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Use a JSON validator to check the request body.
Why this is correct
A JSON validator can identify syntax errors such as unexpected tokens.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase the timeout value for the HTTP request.
Why it's wrong here
Timeout does not cause a 400 error; it would cause a timeout error.
✗
Check the API key validity in the header.
Why it's wrong here
An invalid API key would return 401 Unauthorized, not a JSON parsing error.
✗
Review the API documentation for required fields.
Why it's wrong here
Missing required fields would cause a different error; this error is about malformed JSON.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the ability to map specific HTTP status codes and error messages to the correct troubleshooting tool, and the trap here is that candidates may confuse a JSON syntax error (400) with an authentication error (401/403) or a missing-field error (422), leading them to choose options like checking the API key or reviewing documentation instead of using a JSON validator.
Detailed technical explanation
How to think about this question
JSON parsing errors at a specific character position (like position 42) are typically caught by the server's JSON deserializer (e.g., Python's `json` module or Java's Jackson) before any business logic runs. Tools like `jq` can be used to validate and format JSON from the command line, and many IDEs (e.g., VS Code) have built-in JSON validation that highlights syntax errors in real time. In a real-world scenario, a developer might accidentally include a trailing comma or unescaped control character in a JSON string, which a validator would immediately flag.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 200-901 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Understanding and Using APIs — This question tests Understanding and Using APIs — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use a JSON validator to check the request body. — The HTTP 400 status code indicates a client-side error, and the response body explicitly states 'Invalid JSON: unexpected token at position 42'. This means the request body contains malformed JSON. A JSON validator (e.g., jsonlint.com, jq, or a library like `json.loads()` in Python) will parse the JSON and pinpoint the exact syntax error (e.g., a missing comma, extra brace, or unescaped quote) at the specified position, allowing the developer to fix the request body quickly.
What should I do if I get this 200-901 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.