DNS — Domain Name System: maps domain names to IP addresses
JWT — JSON Web Token: signed token for authentication; header.payload.signature
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A job description states: "You will design and maintain REST APIs consumed by web and mobile clients." What does REST stand for, and what is a REST API?
REST = Representational State Transfer. An architectural style for building web APIs, defined by Roy Fielding in 2000. "RESTful" APIs follow REST constraints and are the dominant style for web services today.
Key REST constraints: • Stateless — each request contains all information needed; the server holds no client session state • Uniform interface — standard HTTP methods: GET (read), POST (create), PUT/PATCH (update), DELETE (remove) • Resource-based — URLs represent resources, not actions: /users/42 not /getUser?id=42 • JSON — the standard data format for REST APIs today (though not required by REST itself)
REST vs. the alternatives: • REST — simple, widely understood, HTTP-based • GraphQL — client specifies exactly what data it needs; Facebook invented it • gRPC — Google's binary protocol over HTTP/2; fast for microservices • SOAP — XML-based, older enterprise standard; much more verbose than REST • WebSocket — persistent bidirectional connection; used for real-time (chat, live feeds)
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A DevOps engineer references a CI/CD pipeline. A colleague asks what CI/CD means. Which answer is correct?
Continuous Integration (CI): Every time a developer commits code, an automated pipeline runs: build → unit tests → integration tests → code quality checks. Goal: catch problems immediately, never let the main branch break. "The CI pipeline failed on the authentication tests."
Continuous Delivery (CD): The software is always in a releasable state after passing CI. Deploying to production requires a human approval button. "We use CD — every Thursday we press the button to ship."
Continuous Deployment (also CD): Every commit that passes all automated tests is automatically deployed to production — no human button. Used by companies like Netflix, Etsy, Amazon. "We do continuous deployment — if tests pass, it goes live."
An interviewer asks: "Can you explain OOP and name the four pillars?" What does OOP stand for, and which option correctly lists the four pillars?
OOP = Object-Oriented Programming. A programming paradigm that organises code around objects — data structures that combine state (fields/properties) and behaviour (methods).
The four pillars:
1. Encapsulation — bundling data and methods together; hiding internal implementation details. A class exposes a public interface but hides how it works internally. "The User class encapsulates the password hashing logic."
2. Inheritance — a class inherits properties and methods from a parent class. Enables code reuse and hierarchical relationships. "AdminUser extends User — AdminUser inherits all User methods plus adds admin-specific ones."
3. Polymorphism — objects of different classes can be treated as instances of a common parent class. The same interface behaves differently based on the actual object. "shape.draw() behaves differently for Circle, Square, and Triangle."
4. Abstraction — exposing only necessary details; hiding complexity. A developer uses a Database class without knowing how connection pooling works internally.
A backend developer says: "We need to set up DNS records before the domain goes live — specifically an A record and a CNAME." What does DNS stand for and what does it do?
DNS = Domain Name System. The distributed system that maps domain names to IP addresses — the internet's phone book. Without DNS, you'd need to remember 93.184.216.34 instead of example.com.
Common DNS record types: • A record — maps a domain to an IPv4 address: example.com → 93.184.216.34 • AAAA record — maps to IPv6 address • CNAME — Canonical Name; alias one hostname to another: www.example.com → example.com • MX record — Mail Exchange; routes email: directs @example.com to a mail server • TXT record — text values; used for domain verification, SPF (email spam prevention), and DKIM • NS record — Name Server; identifies which DNS servers are authoritative for the domain
DNS TTL (Time to Live): how long DNS resolvers cache a record before re-querying. A low TTL (60s) means changes propagate quickly. A high TTL (86400s = 24h) is efficient but slow to update.
DNS propagation: after changing DNS settings, it can take minutes to 48 hours for the change to reach all resolvers worldwide.
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A developer posts a PR description: "Authentication is handled using JWT tokens. The token is signed with RS256 and expires after 15 minutes." What does JWT stand for and what is it?
JWT = JSON Web Token (pronounced "jot"). A compact, self-contained token for securely passing information between parties. Defined in RFC 7519.
JWT structure — three base64-encoded parts separated by dots: header.payload.signature
• Header — algorithm type: {"alg":"RS256","typ":"JWT"} • Payload — the claims (data): {"sub":"user_42","role":"admin","exp":1742000000} • Signature — cryptographic proof the token hasn't been tampered with
Common JWT claims: • sub (subject) — usually a user ID • exp (expiry) — Unix timestamp when the token expires • iat (issued at) — when the token was created • role / scope — custom claims for authorisation
Signing algorithms: • HS256 — HMAC-SHA256 (symmetric: same secret to sign and verify) • RS256 — RSA-SHA256 (asymmetric: private key signs, public key verifies — more secure)
Security note: JWTs are signed (tamper-proof) but not encrypted by default. The payload is base64-encoded, not hidden. Never store secrets in JWT payloads.
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Sarah, a junior developer, received this Slack message from her senior: 'Fix the build pipeline – it's failing again! CI/CD needs to be more reliable.' What does CI/CD stand for in this context?
CI/CD stands for Continuous Integration / Continuous Delivery. It's a practice that automates the software development lifecycle, from code integration to deployment. The Slack message highlights the need for reliability in this automated process, meaning frequent integration and delivery cycles.
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During a standup meeting, Mark says, 'We're using OOP to design our new user interface components. We want to encapsulate the data and behavior related to each UI element.' What does OOP stand for in this scenario?
OOP stands for Object-Oriented Programming. This paradigm focuses on organizing code around 'objects,' which combine data and methods that operate on that data. Using OOP allows developers to model real-world entities more effectively and promotes reusability and maintainability of the UI components.
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Reviewing a pull request, David writes: 'I've implemented the API endpoint using REST principles. I'm returning JSON data formatted as a standard resource.' What does REST stand for in this context?
REST stands for Representational State Transfer. It's an architectural style for designing networked applications based on a set of constraints that make those applications scalable, flexible, and easy to understand. The JSON data formatted as a standard resource aligns with the core principles of RESTful APIs.
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Maria is configuring a new website. Her IT manager instructs her to 'set up DNS records for the domain.' What does DNS stand for?
DNS stands for Domain Name System. It's a hierarchical and distributed naming system that translates human-readable domain names (like `google.com`) into IP addresses, which computers use to locate each other on the internet. This is essential for websites to be accessible.
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During a sprint planning meeting, the team discusses using JWT tokens for user authentication. Liam asks, 'What does JWT stand for?' Which of the following best explains its meaning?
JWT stands for JSON Web Token. It's a compact, self-contained way to securely transmit information between parties as a JSON object. Crucially, it's *not* related to any specific programming language or toolkit; the 'JSON' part of the acronym is key.
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You are reviewing a code commit message: 'Implemented a new feature using OOP principles to create reusable and maintainable components.' What does OOP stand for in this context?
OOP stands for Object-Oriented Programming. This paradigm focuses on organizing code around 'objects' which combine data and methods that operate on that data. It's a fundamental approach to software design promoting modularity and reusability.
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A Slack message from the QA team reads: 'The API is returning 503 errors. We suspect a problem with our CDN – it's caching outdated responses.' What does CDN stand for in this scenario?
CDN stands for Content Delivery Network. It's a geographically distributed network of servers that caches static content (like images and JavaScript files) to deliver it quickly to users based on their location. This dramatically improves API response times.
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During a code review, you see the following comment: 'This endpoint uses RESTful principles for data retrieval and manipulation.' What does REST stand for in this context?
REST stands for Representational State Transfer. It's an architectural style for designing networked applications that uses standard HTTP methods (GET, POST, PUT, DELETE) to interact with resources identified by URLs. It emphasizes statelessness and uniform interfaces.
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A senior developer explains to a junior developer: 'We're using CI/CD to automate our build and deployment process.' What does CI/CD stand for in this context?
CI/CD stands for Continuous Integration/Continuous Delivery (or sometimes Continuous Deployment). It's a development practice that automates the stages of software development – from code integration to testing and deployment. The goal is faster feedback cycles and more reliable releases.
What does the "IT Acronyms & Abbreviations" vocabulary exercise cover?
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