Software engineering guides: DSA, APIs, cloud and DevOps

These software engineering guides cover data structures and algorithms, APIs, containers, cloud, CI/CD, system design and the developer tools worth learning for 2027. Code samples are run before they are published, and the guides say what could not be run.

Last updated: 11 November 2026.

How do you learn DSA and Big O?

Time complexity and Big O notation for beginners: Big O notation for beginners: the classes from O(1) to O(2^n) with examples, how to read code, amortised cost, space complexity and the limits of Big O.
Sorting algorithms explained: bubble, merge and quick sort: Sorting algorithms explained with a worked pass on 5 elements, best, average and worst time, space and stability, and what Python and Java use.
Binary search explained with code in Python, C++ and JavaScript: Binary search explained with tested Python, C++ and JavaScript code: 20 steps for 1,000,000 items, the safe midpoint, lower bound and search on the answer.
Binary tree traversal: inorder, preorder, postorder and level order: Binary tree traversal on one 9-node example: inorder, preorder, postorder and level order, with recursive and iterative Python code and complexity.
Heap data structure and priority queue explained with examples: Heap data structure and priority queue explained with a 6-item trace, heapify in O(n), heap sort, and the Python, Java and C++ priority queue APIs.
Sliding window and two pointers: problem patterns with examples: Sliding window and two pointers explained with 6 tested Python problems, when each pattern applies, and how both cut O(n^2) brute force to O(n).

How do APIs, microservices and containers work?

REST API explained: methods, status codes and design basics: A REST API exposes resources at URLs and uses HTTP methods and status codes. See PUT vs PATCH, 401 vs 403 and a tested example, with RFC 9110 definitions.
GraphQL vs REST: differences, trade-offs and when to use each: GraphQL vs REST: endpoints, response shape, caching, versioning and errors compared, with a tested Node example. GraphQL spec edition: September 2025.
Microservices vs monolith: key differences and when to choose each: Microservices vs monolith compared on 6 criteria, including deployment, scaling and data, plus the modular monolith middle path and named write-ups.
Docker for beginners: images, containers and a first deployment: Docker for beginners: images vs containers, a 5-line Dockerfile for a Python app, key commands, ports, volumes and Compose, taken from Docker's own docs.
What is Kubernetes? Pods, deployments and services for beginners: What is Kubernetes? An open source platform for running containers at scale, explained with five manifests (Pod, Deployment, Service) checked against 1.37.
What is CI/CD? Pipelines explained with a GitHub Actions example: What is CI/CD? Continuous integration and delivery explained with the stages of a pipeline and a GitHub Actions workflow linted with actionlint 1.7.12.

What should you know about system design and cloud?

System design basics for freshers: a beginner framework with examples: System design basics for freshers: a 7-step framework, 5 core building blocks and a URL shortener designed with a tested estimate of 3858 reads per second.
AWS vs Azure vs Google Cloud: which cloud to learn first in 2027: AWS vs Azure vs Google Cloud for beginners: entry certifications, matching services, cloud roles and Q3 2026 market share, to help pick a first cloud.
Cloud engineer roadmap for 2027: skills, certifications and projects: A cloud engineer roadmap for 2027 in eight stages, from Linux and networking to infrastructure as code, with subnet and S3 scripts tested on Python 3.12.
DevOps engineer roadmap for 2027: skills, tools and projects: A DevOps roadmap for 2027 in ten stages, from Linux and Git to Kubernetes and Terraform, with DORA's five delivery metrics and a tested Python example.

Which developer tools and platforms help?

Best coding practice platforms in 2027 for interviews and contests: Coding practice platforms as of 11 November 2026: LeetCode (4110 problems), HackerRank, Codeforces, CodeChef, AtCoder, CSES and four more, with limits.
Best API testing tools in 2027: Postman, Bruno, Insomnia and more: API testing tools compared as of 11 November 2026: Postman, Bruno, Insomnia, Hoppscotch, curl, HTTPie, Swagger UI and k6, with storage and one limit each.
Best cybersecurity tools for beginners in 2027, and legal practice: Cybersecurity tools for beginners as of 11 November 2026: Wireshark, Nmap, Burp Suite, ZAP and more, plus legal practice labs and what India's IT Act says.
QA and software testing roadmap for 2027: manual to automation: A software testing roadmap for 2027: ISTQB test levels, bug reports, API tests, Playwright vs Selenium and CI, with a pytest suite run on Python 3.12.
Flutter vs React Native vs native: which mobile stack to learn in 2027: Flutter vs React Native vs native compared on language, rendering and iOS build needs, with releases as of 7 November 2026 and a first pick for beginners.
Full stack developer roadmap for 2027: what to learn and in what order: A full stack developer roadmap in nine stages, from HTML and JavaScript to APIs, databases, testing and deployment, with Stack Overflow 2026 survey data.
Coder vs programmer vs developer vs software engineer: Coder vs programmer vs developer vs software engineer compared using US O*NET and BLS definitions, India's NCO 2015 and Naukri Campus, with CV advice.

Forward Deployed Engineer cohort, Leap by Masai: Leap by Masai cohort for engineers: production Python, APIs, cloud deployment, LLMs, retrieval, agents and client engagement.
Certificate Programme in Cybersecurity and Ethical Hacking in the AI Era, IITM Pravartak: Online programme from IITM Pravartak: ethical hacking, security operations, cloud security, DevSecOps, AI security and a breach-response capstone.

Frequently asked questions

What should a fresher learn first in software engineering?

Start with one language, Big O notation, arrays and sorting and searching, then APIs. The DSA guides use runnable code, and the full-stack roadmap shows how the pieces fit into a first project.

What is the difference between REST and GraphQL?

REST exposes many endpoints that return fixed shapes, while GraphQL exposes one endpoint where the client asks for the fields it wants. The comparison guide has a table of trade-offs and a tested example.

Do beginners need Kubernetes?

Not at first. The Kubernetes guide explains pods, deployments and services and says when a cluster is unnecessary, and the Docker guide for beginners covers containers, which are the usual first step.