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Start DEVCOR Practice Quiz →DEVCOR APIs Question Bank (21 Questions)
Browse all 21 practice questions covering Using APIs for the DEVCOR certification exam. Each question includes the full answer and a detailed explanation to help you understand the concepts.
- Question 1Using APIs
Which API pagination approach uses a cursor/token to fetch the next page of results?
Show Answer & Explanation
Correct Answer: BExplanation:Cursor-based pagination uses an opaque cursor/token (often the last item's ID) to fetch the next page. It's more efficient than offset-based for large datasets because it doesn't skip rows and handles real-time data changes better.
- Question 2Using APIs
What advantage does GraphQL provide over traditional REST APIs?
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Correct Answer: BExplanation:GraphQL allows clients to request exactly the data they need in a single query, avoiding over-fetching (getting unnecessary fields) and under-fetching (needing multiple requests). The schema defines available types and relationships.
- Question 3Using APIs
What is API rate limiting and how should clients handle HTTP 429 responses?
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Correct Answer: BExplanation:Rate limiting restricts the number of API requests a client can make per time window (e.g., 100 requests/minute). HTTP 429 (Too Many Requests) signals the limit is exceeded; clients should use exponential backoff with jitter before retrying.
- Question 4Using APIs
Which HTTP method is idempotent and used to update an entire resource?
Show Answer & Explanation
Correct Answer: BExplanation:PUT is idempotent — calling it multiple times with the same data produces the same result. It replaces the entire resource at the specified URI. PATCH partially updates a resource; POST creates a new resource (not idempotent).
- Question 5Using APIs
What is pagination in REST APIs?
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Correct Answer: BExplanation:Pagination strategies: offset-based (?page=2&per_page=25), cursor-based (after=eyJpZCI6MTB9), keyset-based (after_id=100). Include total count, next/prev links. Cursor-based is preferred for large/changing datasets.
- Question 6Using APIs
How do webhooks differ from polling for receiving event notifications from an API?
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Correct Answer: BExplanation:Webhooks use a push model — the server sends HTTP POST requests to a registered callback URL when events occur. This is more efficient than polling (repeatedly checking for changes), reducing latency and unnecessary API calls.
- Question 7Using APIs
What does HATEOAS (Hypermedia as the Engine of Application State) add to a REST API?
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Correct Answer: BExplanation:HATEOAS includes hypermedia links in API responses that tell clients what actions are available and how to navigate the API. This makes APIs self-descriptive and loosely coupled — clients don't need hardcoded URLs.
- Question 8Using APIs
Which HTTP status code range indicates client-side errors in a REST API?
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Correct Answer: BExplanation:4xx status codes indicate client errors: 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found, 409 Conflict, 422 Unprocessable Entity, 429 Too Many Requests. 5xx codes indicate server errors; 2xx indicates success.
- Question 9Cisco Platforms
Which Cisco security platform provides REST APIs for managing firewall rules, access policies, and intrusion detection?
Show Answer & Explanation
Correct Answer: BExplanation:Cisco FMC provides REST APIs for programmatically managing Firepower Threat Defense (FTD) devices — creating/modifying access control policies, intrusion rules, network objects, NAT rules, and retrieving security event data.
- Question 10Using APIs
What are key differences between REST and SOAP APIs?
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Correct Answer: BExplanation:REST uses standard HTTP methods (GET/POST/PUT/DELETE) with flexible formats (JSON preferred). SOAP uses XML envelopes, WSDL contracts, and supports WS-Security, WS-ReliableMessaging. REST is simpler; SOAP is more enterprise/transactional.
- Question 11Using APIs
What is the relationship between YANG models and RESTCONF/NETCONF APIs on network devices?
Show Answer & Explanation
Correct Answer: BExplanation:YANG defines the data model (structure, constraints, types). NETCONF (XML/SSH) and RESTCONF (JSON or XML/HTTPS) are protocols that use YANG models to read/write configuration and operational data on network devices.
- Question 12Using APIs
What is the purpose of API rate limiting?
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Correct Answer: BExplanation:Rate limiting controls how many API requests a client can make within a time window, protecting the API from abuse, DDoS, and ensuring fair resource allocation across consumers.
- Question 13Using APIs
What is pagination in API responses used for?
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Correct Answer: BExplanation:Pagination splits large datasets into pages (using offset/limit or cursor-based approaches), reducing response payload size and server load while improving client performance.
- Question 14Using APIs
What is the purpose of API pagination?
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Correct Answer: BExplanation:Pagination divides large datasets into pages (offset/limit, cursor-based, or keyset), reducing response payload, server memory, and improving client-side rendering performance.
- Question 15Using APIs
What is GraphQL and how does it differ from REST?
Show Answer & Explanation
Correct Answer: BExplanation:GraphQL lets clients request exactly the data needed with typed schemas, solving REST's over-fetching (getting too much data) and under-fetching (needing multiple endpoints) problems.
- Question 16Using APIs
What is API rate limiting and why is it important?
Show Answer & Explanation
Correct Answer: BExplanation:Rate limiting caps requests per client per time window (e.g., 1000/hour), preventing DoS attacks, ensuring fair usage across clients, and protecting backend services from overload.
- Question 17Using APIs
What is rate limiting in APIs?
Show Answer & Explanation
Correct Answer: BExplanation:Rate limiting protects APIs: token bucket/sliding window algorithms, communicated via headers (X-RateLimit-Remaining, Retry-After). Prevents abuse, ensures fair usage, and protects backend resources.
- Question 18Application Deployment and Security
How does a JSON Web Token (JWT) work for API authentication?
Show Answer & Explanation
Correct Answer: BExplanation:JWT is a self-contained token with three parts: header (algorithm), payload (claims like user ID, roles, expiry), and signature. The server verifies the signature to authenticate requests without maintaining server-side session state.
- Question 19Software Development and Design
What is the purpose of a REST API's idempotent methods?
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Correct Answer: BExplanation:Idempotent methods (GET, PUT, DELETE) produce the same result regardless of how many times they're called, making APIs resilient to retries and network issues.
- Question 20Using APIs
Which authentication mechanism uses tokens obtained after initial authentication to authorize subsequent API requests?
Show Answer & Explanation
Correct Answer: BExplanation:OAuth 2.0 Bearer Tokens are obtained through an authorization flow and included in subsequent API request headers, providing secure, scalable authentication without resending credentials.
- Question 21Using APIs
Which data format is MOST commonly used for REST API request and response bodies?
Show Answer & Explanation
Correct Answer: BExplanation:JSON is the de facto standard for REST APIs due to its lightweight structure, readability, native JavaScript support, and broad library support across all programming languages.
Key APIs Concepts for DEVCOR
DEVCOR APIs Exam Tips
Using APIs questions in DEVCOR are typically scenario-based. Focus on service-level decision making aligned to official exam objectives. Priority concepts: rest, api, graphql, webhook, pagination, rate limit.
What DEVCOR Expects
- Anchor your answer in select the most practical, secure, and scalable answer for the stated scenario.
- APIs scenarios for DEVCOR are frequently mapped to Domain 2 (20%), so read the objective carefully before picking controls or architecture.
- Expect multi-service scenarios where APIs interacts with IAM, networking, storage, or observability patterns rather than appearing as an isolated service question.
- When two options are both technically valid, prefer the choice that best aligns with the exam's operational scope (Professional) and managed-service best practices.
High-Value APIs Concepts
- Know the core APIs building blocks cold: rest, api, graphql, webhook.
- Review the edge-case features and limits for pagination, rate limit; these details are commonly used to differentiate answer choices.
- Practice service-integration reasoning: how APIs pairs with Software Design, Cisco Platforms in real deployment patterns.
- For DEVCOR, explain why the chosen APIs design meets reliability, security, and cost expectations better than the alternatives.
Common DEVCOR Traps
- Watch for answers that partially solve the requirement but miss operational constraints.
- Questions in Using APIs often include distractors that look correct for APIs but violate least-privilege, durability, or availability requirements.
- Avoid picking options purely by feature name; validate data path, failure handling, and governance impact before answering.
- If the prompt hints at automation or repeatability, eliminate manual-only operational answers first.
Fast Review Checklist
- Can you compare at least two APIs implementation paths and justify which one best fits the scenario?
- Can you map the chosen answer back to Using APIs (20%) outcomes for DEVCOR?
- Can you explain security and access boundaries for APIs without relying on default-open assumptions?
- Can you describe how APIs integrates with Software Design and Cisco Platforms during failure, scaling, and monitoring events?