Interview preparation roadmap · Technology
Low-level C, microcontrollers, RTOS and concurrency, and debugging on real hardware.
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- 01Interview foundations
- 02Coding
- 03Firmware core
- 04Role-specific
- 05Practice
- 06Company & final prep
01Interview foundations
What every interviewer sees first.
01.1Resume
A one-page resume you can defend line by line.
What this covers
- One-page format — Reverse-chronological, clean fonts, no photos or tables that confuse parsers.
- Project bullets — Action + what you built + a number (users, speed, accuracy).
- Skills section — Only skills you can answer questions on for two minutes.
- ATS readability — Export a text-based PDF and check it with a parser.
- Working links — GitHub, LinkedIn and a live project link that open.
- Tailoring — Reorder bullets to match the job description.
What to practise
- Run your PDF through a parser test
- Rewrite each bullet as action + result
- Remove any skill you can't explain for 2 minutes
Common questions
- Walk me through your resume.
- Which project here are you most proud of, and why?
- Why is this skill on your resume?
Free resources
- OpenResume — Free ATS-friendly resume builder and parser test (Free)
- Jake's Resume (Overleaf) — The LaTeX resume template most SDE freshers use (Free)
- Resume Worded — Resume and LinkedIn scoring (Free plan)
- Jobscan — Match your resume against a job description (Free plan)
Free courses
- Professional Resume Writing — Alison (Free course)
- Resume, Networking, and Interview Skills — Fullbridge (Free to audit)
01.2Tell me about yourself
A 60–90 second answer: present, past, why this role.
What this covers
- Present — Who you are now: degree, year, focus.
- Past — One or two proof points: a project, internship or result.
- Future — Why this role and this company next.
- Length — 60–90 seconds; stop before you list everything.
- Delivery — Calm pace and eye contact, not a memorised script.
What to practise
- Write it, then say it out loud 5 times
- Record yourself and cut anything over 90 seconds
Common questions
- Tell me about yourself.
- Why should we hire you?
- Where do you see yourself in a few years?
Free resources
- Google Interview Warmup — Free spoken mock interview that prints your transcript (Free)
- BBC Learning English — Structured free English lessons and podcasts (Free)
Free courses
- English@Work: Basic Job Interview Skills — The Hong Kong Polytechnic University (Free to audit)
- Job Interview Preparation For Tech Professionals — University of Cape Town (Free to audit)
01.3Behavioral & STAR
Stories about teamwork, conflict and failure, told with STAR.
What this covers
- STAR structure — Situation, task, action, result. Spend most of the time on action.
- Story bank — 6–8 real stories you can reuse across questions.
- Teamwork & conflict — Disagreeing respectfully and what you changed.
- Failure & weakness — A real one, what you learned, what you do now.
- Ownership — Times you took initiative without being asked.
- Common HR questions — Why us, why you, strengths, relocation.
What to practise
- Write 6 stories in STAR form
- Map each story to 2–3 common questions
- Practise one story with a friend
Common questions
- Tell me about a time you failed.
- Describe a conflict in a team and what you did.
- What is your biggest weakness?
Free resources
- Tech Interview Handbook — Free guide to coding and behavioral interviews (Free)
- Google Interview Warmup — Free spoken mock interview that prints your transcript (Free)
- Pramp / Exponent peer mocks — Free peer-to-peer mock interviews (Free plan)
Free courses
- Master Behavioral Interviews (for Software Engineers) — freeCodeCamp (Free video)
- Behavioral Interview Practice for Computer Science Students — CodeSignal (Free to audit)
- Soft Skills For Tech Professionals — University of Cape Town (Free to audit)
02Coding
C and problem solving.
02.1Programming fundamentals
One language you know well: syntax, memory, complexity.
What this covers
- One language deeply — C++, Java or Python: syntax, standard library, quirks.
- Time & space complexity — Big-O of loops, recursion and common operations.
- Recursion — Base cases, the call stack, when it overflows.
- Memory basics — Stack vs heap, references vs values, garbage collection.
- Strings & arrays — Immutability, copying and slicing costs in your language.
- Debugging — Reading errors, dry runs, using a debugger.
What to practise
- Solve 10 easy problems without an IDE's help
- Explain the complexity of each solution aloud
Common questions
- What is the time complexity of your solution?
- What happens in memory when you call a function?
- Difference between an array and a linked list?
Free resources
- Harvard CS50x — The best first CS course there is (Free)
- HackerRank — Where many campus tests actually run (Free)
- GeeksforGeeks — Company-wise questions and theory (Free plan)
Free courses
- CS50's Introduction to Programming with Python (CS50P) 2022 — Harvard University (Free video)
- MIT 6.100L Introduction to CS and Programming using Python, Fall 2022 — Massachusetts Institute of Technology (Free video)
- Programming in Modern C++ — IIT Kharagpur (Free course)
02.2Data structures & algorithms
The core problem-solving topics commonly assessed in software interviews.
What this covers
- Arrays & hashing — Frequency maps, prefix sums, duplicates.
- Two pointers & sliding window — Pairs, subarrays and substrings in O(n).
- Stacks & queues — Brackets, monotonic stacks, BFS queues.
- Linked lists — Reversal, cycle detection, merging.
- Trees & BST — Traversals, height, LCA, validation.
- Graphs — BFS, DFS, topological sort, shortest paths.
- Binary search — On sorted arrays and on the answer.
- Dynamic programming — 1D and 2D DP, from climbing stairs to knapsack.
What to practise
- Follow one list end to end, not five
- Say the brute force first, then improve it
- One timed problem a day
Common questions
- What is the difference between BFS and DFS?
- How does a hash map handle collisions?
- Find the first non-repeating character in a string.
Free resources
- NeetCode 150 — A curated ordered list instead of 3000 random problems (Free)
- Striver's A2Z DSA sheet — India's most-followed DSA sheet (Free)
- LeetCode — The default interview practice set (Free plan)
- GeeksforGeeks — Company-wise questions and theory (Free plan)
Free courses
- Data Structures and Algorithms Design — IIT Kanpur (Free course)
- MIT 6.006 Introduction to Algorithms, Spring 2020 — Massachusetts Institute of Technology (Free video)
- Neetcode 150 Course - All Coding Interview Questions Solved — freeCodeCamp (Free video)
03Firmware core
The main rounds.
03.1Embedded C & microcontrollers
Low-level C and how code runs on microcontrollers.
What this covers
- Pointers & memory — Volatile, const, memory-mapped registers.
- Bit manipulation — Set, clear, toggle, masks.
- Interrupts — ISRs and keeping them short.
- Timers & GPIO — Driving pins and measuring time.
- RTOS basics — Tasks, scheduling, semaphores.
- Debugging — Debuggers, logic analysers, printf.
What to practise
- Blink and debounce a button on a microcontroller board
- Write bit-manipulation helpers and test them
Common questions
- What does volatile mean?
- How do you set a bit in a register?
- What is an interrupt?
Free resources
- Arduino documentation — Official Arduino guides and tutorials (Free)
- NPTEL — IIT/IISc course videos across engineering (Free)
- All About Circuits textbook — Free electronics and electrical textbook (Free)
Free courses
- Embedded Systems Design — IIT Kharagpur (Free course)
- Embedded System Design with ARM — IIT Kharagpur (Free course)
- ACM India Summer School on IoT and Embedded Systems — IIT Madras (Free course)
03.2Digital electronics & protocols
Electronics and communication protocols embedded roles expect.
What this covers
- Digital logic — Gates, flip-flops, counters.
- Analog basics — Voltage dividers, op-amps, ADC/DAC.
- Serial protocols — UART, SPI, I2C and when to use each.
- Power — Regulators, current limits, low-power modes.
- Reading datasheets — Finding pinouts, timing and limits.
What to practise
- Read a sensor over I2C and log values
- Compare UART, SPI and I2C in a table
Common questions
- Difference between SPI and I2C?
- What is a pull-up resistor for?
Free resources
- All About Circuits textbook — Free electronics and electrical textbook (Free)
- Arduino documentation — Official Arduino guides and tutorials (Free)
- NPTEL — IIT/IISc course videos across engineering (Free)
Free courses
- Digital Electronic Circuits — IIT Kharagpur (Free course)
- Digital System design with PLDs and FPGAs — IISc Bangalore (Free course)
- Digital Image Processing — IIT Kanpur (Free course)
03.3Operating systems
Processes, threads, scheduling, memory and deadlocks.
What this covers
- Processes & threads — Differences and context switching.
- CPU scheduling — FCFS, SJF, round robin, priority.
- Synchronisation — Race conditions, mutexes, semaphores.
- Deadlocks — The four conditions, prevention, avoidance.
- Memory management — Paging, segmentation, virtual memory.
- Page replacement — FIFO, LRU, optimal.
What to practise
- Draw the process state diagram from memory
- Explain a deadlock with a real example
Common questions
- Process vs thread?
- What are the four conditions for deadlock?
- What is virtual memory?
Free resources
- OSTEP (Operating Systems: Three Easy Pieces) — Free operating systems book, chapter by chapter (Free)
- GeeksforGeeks — Company-wise questions and theory (Free plan)
Free courses
- Introduction to Operating Systems — IIT Madras (Free course)
- Operating Systems Course for Beginners — freeCodeCamp (Free video)
- Operating System Fundamentals — IIT Kharagpur (Free course)
03.4Concurrency & multithreading
Threads, locks and async code; asked more in back-end and systems roles.
What this covers
- Threads vs processes — Costs, sharing and isolation.
- Race conditions — Shared state and how bugs appear.
- Locks & synchronisation — Mutex, semaphore, deadlock avoidance.
- Async & event loops — Non-blocking I/O models.
- Thread-safe collections — When to use them.
What to practise
- Write a producer–consumer program
- Find and fix a race condition in sample code
Common questions
- What is a deadlock and how do you avoid it?
- Difference between concurrency and parallelism?
Free resources
- OSTEP (Operating Systems: Three Easy Pieces) — Free operating systems book, chapter by chapter (Free)
- GeeksforGeeks — Company-wise questions and theory (Free plan)
04Role-specific
Hardware and tools.
04.1Projects & resume defense
Explaining what you built, why, and what you would change.
What this covers
- The problem — What it solves and for whom.
- Your role — Exactly what you built yourself.
- Architecture — A simple diagram: frontend, backend, database.
- Hardest bug — What broke and how you found it.
- Trade-offs — Why this stack; what you would change now.
- Scale questions — What happens with 10x the users.
What to practise
- Prepare a 2-minute walkthrough per project
- Be ready to draw its architecture
Common questions
- What was the hardest part of this project?
- Why did you choose this tech stack?
- How would it handle 10x more users?
Free resources
- Tech Interview Handbook — Free guide to coding and behavioral interviews (Free)
- Pramp / Exponent peer mocks — Free peer-to-peer mock interviews (Free plan)
Free courses
- Software Engineering Concepts — MIT OpenCourseWare (Free course)
- Build community-driven software projects on GitHub — Microsoft (Free course)
04.2Git & version control
Branches, merges and collaborating on code.
What this covers
- Commits & history — Small commits with clear messages.
- Branching — Feature branches and pull requests.
- Merge vs rebase — When to use which.
- Resolving conflicts — Reading and fixing conflict markers.
- Undoing safely — revert, reset and restore.
What to practise
- Contribute a small fix to an open-source repo
- Practise resolving a merge conflict
Common questions
- Difference between merge and rebase?
- How do you undo a pushed commit?
Free resources
- Pro Git book — The free official Git book (Free)
- GitHub — Where your projects live (Free)
- freeCodeCamp — Full curricula with projects, certificates at the end (Free)
Free courses
- Getting Started with Git and GitHub — IBM (Free course)
- HTML,CSS,JavaScript, Project, Git & GitHub — Apna College (Free video)
- Git & GitHub Tutorial for Beginners — The Net Ninja (Free video)
04.3Linux & the command line
Everyday commands, permissions and processes.
What this covers
- Navigation & files — ls, cd, find, grep, less.
- Permissions — chmod, chown, users and groups.
- Processes — ps, top, kill, background jobs.
- Networking tools — curl, ping, ss, dig.
- Shell scripting — Variables, loops, pipes, exit codes.
- Logs & services — journalctl, systemctl, tail -f.
What to practise
- Solve the first 15 levels of a command-line wargame
- Write a script that backs up a folder daily
Common questions
- How do you find which process uses a port?
- What does chmod 755 mean?
Free resources
- OverTheWire: Bandit — Command-line security games, level by level (Free)
- Professor Messer — Free networking and IT support video courses (Free)
- MIT OpenCourseWare — Real MIT course material, free (Free)
Free courses
- Command Line Hacking – Over The Wire Bandit Walkthrough (CTF Wargame) — freeCodeCamp (Free video)
- Linux for Absolute Beginners — Alison (Free course)
- Linux Basics: The Command Line Interface — Dartmouth College (Free to audit)
05Practice
Saying it out loud is a different skill.
05.1Technical mock interviews
At least two full coding mocks before the real one.
What this covers
- Thinking aloud — Narrate your approach before and while coding.
- Clarifying questions — Confirm inputs, scale and edge cases first.
- Handling hints — Take them gracefully and adapt.
- "I don't know" — Say what you do know and how you would find out.
- Review the recording — Fillers, pace, unclear explanations.
What to practise
- Do two peer mock interviews
- Record one spoken mock and listen back
Common questions
- Walk me through your approach before you code.
- How would you test this?
Free resources
- Pramp / Exponent peer mocks — Free peer-to-peer mock interviews (Free plan)
- Google Interview Warmup — Free spoken mock interview that prints your transcript (Free)
- Tech Interview Handbook — Free guide to coding and behavioral interviews (Free)
Free courses
- Software Engineering Job Interview – Full Mock Interview — freeCodeCamp (Free video)
05.2Technical communication
Explaining your thinking clearly in English.
What this covers
- Structure — Big picture first, then details.
- Plain words — Explain without jargon.
- Checking in — "Does that make sense so far?"
- Written English — Clear emails and follow-ups.
What to practise
- Explain one project to a non-CS friend
- Record a 2-minute explanation of your best project and listen back
Common questions
- Explain recursion to a 10-year-old.
Free resources
- BBC Learning English — Structured free English lessons and podcasts (Free)
- LanguageTool — Grammar checking that isn't Grammarly (Free plan)
Free courses
- Technical Communications for Engineers — IIT Roorkee (Free course)
06Company & final prep
The last 48 hours.
06.1Company research
The product, the role, the job description and recent news.
What this covers
- The business — What it sells and to whom.
- The role — What the job description really asks for.
- Recent news — Launches, results, announcements.
- Interview format — The rounds, if the company shares them.
- Your fit — Three reasons, matched to the job description.
What to practise
- Write 3 reasons you want this role
- Match 3 JD lines to your experience
Common questions
- Why do you want to work here?
- What do you know about our product?
Free resources
- GeeksforGeeks — Company-wise questions and theory (Free plan)
- Tech Interview Handbook — Free guide to coding and behavioral interviews (Free)
06.2Questions to ask
Two or three good questions for the end of the interview.
What this covers
- About the team — How work is planned and reviewed.
- About growth — Mentoring, learning, the first 90 days.
- About the product — What is hard right now.
- What to avoid — Questions a quick search answers.
What to practise
- Write 5 questions, keep the best 3
- Prepare one question about the team's own product
Common questions
- Do you have any questions for us?
Free resources
- Tech Interview Handbook — Free guide to coding and behavioral interviews (Free)
06.3Final checklist
Logistics, documents, setup and a calm night before.
What this covers
- Logistics — Time, timezone, link or address.
- Documents — Resume copies, ID, certificates if asked.
- Tech check — Camera, mic, internet, charger.
- Night before — Sleep, light revision, no new topics.
What to practise
- Do a 5-minute tech check the day before
- Lay out documents and clothes the night before
Free resources
- Google Interview Warmup — Free spoken mock interview that prints your transcript (Free)
06.4Job & interview safety
Spot fake offers, payment requests and fake interview links.
What this covers
- Payment requests — Real employers don't charge for jobs or training.
- Email domains — Check it matches the company's own site.
- OTPs & logins — Never share them with anyone.
- Fake interview links — Care with unknown chat apps and downloads.
- Reporting — The 1930 helpline and cybercrime.gov.in.
What to practise
- Check one recent offer against these rules
- Confirm the opening is listed on the company's own careers page
Free resources
- National Cyber Crime Portal — Report online fraud and job scams (Free)
- Have I Been Pwned — Check if your email appears in a data breach (Free)