Frequently asked questions about CodeKairo
Short, plain-language answers about accounts, the problem workbench, bug hunts, pair rooms, mock interviews, rating, XP and streaks.
CodeKairo
- What is CodeKairo?
- CodeKairo is a web-based coding practice and interview-preparation platform for college students and early-career software engineers. It provides DSA problems judged by hidden tests in 13 languages, a DSA roadmap, a daily contest, bug hunts on real code, Java, JavaScript, C++, Python and SQL study plans, AI-led mock interviews, aptitude practice, placement mock tests, a resume ATS analyzer, coding duels, pair-programming rooms, a community feed and one rating, XP and streak system.
- Who is CodeKairo for?
- Students preparing for campus placements and coding rounds, and working developers preparing for technical interviews. Prices are in rupees and the product calendar runs on Indian Standard Time.
- What can I do on CodeKairo without an account?
- Read any problem, bug hunt, study lesson, aptitude question or placement-test pattern, the roadmap, the leaderboard, the pricing page, the community feed, and the duel, pair-room and mock-interview pages. Running or submitting code, recording an aptitude attempt, starting a test, an interview or a duel, enrolling in a plan, posting, and uploading a resume need a free account.
- How does CodeKairo help with coding interview preparation?
- Practise the problems and the DSA roadmap, rehearse the exact round with a mock interview built from the role, round and depth, pair with a friend in a live room, and get your resume past the ATS filter — all on one profile that records what you have actually solved.
- How can students prepare for placements on CodeKairo?
- The aptitude bank covers every section a placement paper draws from with worked solutions; the placement tests are full-length timed mocks on 26 company patterns with a review afterwards; the challenges and roadmap cover the coding round; and the resume analyzer scores a CV against the job description.
Account
- How do I sign up?
- Email and password, Google, or GitHub. A username is chosen at registration and can be changed from your profile later, as long as the new one is free.
- Is it free?
- A free account is free forever, with no trial period and no card on file, and covers problem solving, duels, study plans, aptitude practice and bug hunts without limits, plus a placement mock test every 10 days and a resume analysis a week. Pro, from ₹83 a month, raises those limits. Until 1 January 2027 everything on CodeKairo is free for every account: every plan's limits are lifted — unlimited mock interviews, 30-minute voice rounds and unlimited bug hunts — so no plan is needed until then.
- Does it work on a phone?
- The dashboard, lists and profile do. The workbench is built for a keyboard and a wide screen; it works on a tablet, but you'll want a laptop for real sessions.
- Is there a dark mode?
- Yes, and a light one. The toggle is in the top bar; your choice is remembered and applied before the page paints, so there's no flash on reload.
Challenges
- Which languages can I use?
- JavaScript, TypeScript, Python, Java, C++, C, C#, Go, Kotlin, Swift, Rust, PHP and Ruby — with starter code per language.
- Run vs Submit?
- Run executes against the visible samples plus your custom cases and shows per-case output. Submit runs the hidden tests and produces the recorded verdict.
- Can I customise the workspace?
- Layout presets (standard, mirrored, three-column, vertical), resizable panels, five editor themes, timer mode, auto-pause, sounds and visual alerts. It's all in the settings drawer inside the workbench.
- What if I lose my draft?
- Drafts autosave per problem and language. Timer state is saved too, so a reload picks up where you were.
- Can I bookmark problems or see what I've solved?
- The Challenges list shows solved and attempting status per problem, and you can filter by it. Your full submission history is on the problem's Submissions tab and on your profile.
Bug hunts
- What do I get when I open a hunt?
- The bug report and the code. No line numbers, no hint about where — finding it is the exercise.
- How is a fix judged?
- Hidden tests. A partial fix shows a partial pass count; a complete fix awards 50 XP and counts as an active day.
Pair mode
- How do people join a room?
- With the invite code. Collaborative rooms also let signed-in users join directly up to the participant limit the host set.
- Is there audio?
- Yes, inside the room, alongside chat and typing indicators.
- What happens if the host's tab dies?
- If the host is gone for 20 seconds, the longest-seated participant becomes host and the session carries on; the old host comes back as a guest. A room closes once it has been empty for a minute.
Mock interviews
- What do I configure?
- Role (39), round (16), depth (3), seniority, interview style, stack and focus areas. Save it as a template and rerun it any time.
- Is the session timed?
- Yes. Depth sets the expected length — roughly 25, 40 or 55 minutes — and the session runs against the clock.
Progress
- What moves my rating?
- Accepted submissions. Everyone starts as a Novice at zero; the ranks sit at 100 (Apprentice), 400 (Adept), 900 (Expert) and 1,500 (Master).
- What's XP for?
- Volume. Problems pay by difficulty, bug fixes pay 50 each, and it only ever goes up.
- What breaks a streak?
- A day with no accepted solution — challenge or bug hunt. Runs and failed submissions don't keep it alive.
- Can I see how I compare?
- The leaderboard: three boards — combined XP, problems solved and bugs fixed — each showing the top ten, with your own rank beside it once you have XP on that board.
DSA roadmap
- What is on the road?
- Four tiers — Foundations, Core techniques, Advanced and Mastery — holding 19 stages: Arrays 101, Hashing, Strings, Two Pointers, Sliding Window, Prefix Sums, Stacks, Binary Search, Sorting & Greedy, Intervals, Heaps, Matrix & Grids, Bit Manipulation, Recursion & Backtracking, two Graphs stages, two Dynamic Programming stages and a Capstone. About 150 problems in all.
- How does a stage unlock?
- By clearing the one before it. A stage is cleared once you have accepted submissions on its required number of problems — usually 6 of 8. Progress is derived from your real submissions: a solve made from the catalogue, a duel, the daily contest or a pair room counts too.
- What is in a chest?
- Every tier ends in one. It opens the moment every stage in the tier is cleared and pays, once, the tier's XP (30, 50, 80 or 100) to both XP and rating, plus one to three bonus mock-interview sessions that never expire. Each opened chest is a badge on your profile and a frame around your avatar.
- Is there a certificate?
- Yes, once the last chest is open: an A4 certificate naming you, the completion date and the date each tier was cleared, exported as a PNG from the site.
- Does the roadmap teach the topics too?
- Yes. Every stage has its lessons — about 35 tutorials such as Two Pointers Technique, Sliding Window, Binary Search, Greedy Algorithms, Dijkstra's Algorithm and Dynamic Programming. Each explains the idea and why it works, traces an example step by step, and shows runnable code in C++, Java, Python and JavaScript. Lessons are free, need no account and are never locked.
Study plans
- Which languages have a plan?
- Java (20 modules, 138 lessons, 292 programs), JavaScript (16 modules, 96 lessons, 208 programs), C++ (20 modules, 131 lessons, 281 programs) and Python (20 modules, 134 lessons, 288 programs).
- What does a lesson look like?
- Ten to sixteen minutes of reading, usually two whole-program exercises that run on a real runtime — OpenJDK 18, Node 16, Clang 18 with C++20 or CPython 3.11 — against hidden test cases, and a server-graded quiz with explanations. The last lesson of every module is a checkpoint: 10–15 questions and three programs, cleared at 70%.
- How does the pace work?
- Pick 30, 60 or 90 days when you start. The plan then tells you whether you are on track, ahead or behind, with your projected finish date. It never locks anything — any lesson can be opened at any time.
- Is it free?
- Yes, on every plan, with no daily cap. Finishing a track pays +100 XP and unlocks a certificate, and every module can be downloaded as a PDF to read offline.
Daily contest
- When does the problem change?
- Once per UTC day — 05:30 in India. Difficulty follows the weekday: easy on Monday and Wednesday, medium on Tuesday, Thursday and Friday, hard on Saturday and Sunday. Everyone gets the same problem, and a problem is not reused for a year.
- How is the day's board ranked?
- By your time from opening the problem to the accepted submission, plus five minutes for every wrong submission before it — a compile error costs nothing. Ties go to whoever finished first.
- What are the points?
- Easy 3, medium 4, hard 5, on the contest's own ladder with monthly and all-time standings, separate from XP.
- Does the daily contest pay XP?
- Yes, when the day closes at midnight UTC (05:30 in India) and the next problem is set: 20 XP to everyone who solved it that day, plus 15 to the fastest on the day's board and 10 to the second fastest. Each solver gets a notification saying what they earned and why. It comes on top of the problem's normal first-solve XP.
- Does a problem I solved earlier count?
- No — you have to submit it again on the day. Consecutive days solved build a contest streak, separate from the solving streak, and the calendar shows every day as solved, attempted or missed.
Duels
- How are opponents matched?
- In the public queue you are seated in the first waiting duel of the same mode within ±200 rating; the band widens by 100 every ten seconds until someone fits. Private rooms use a six-character code and start once everyone has pressed Ready.
- What decides the winner?
- The first accepted submission on the problem or bug hunt, wherever it was made. There is no time limit, so a hard problem can take as long as it takes. If your opponent leaves and does not come back within two minutes, you can claim the win.
- What about cheating?
- The clipboard is locked, switching tabs or apps hides the board, and screenshot shortcuts are refused. Each attempt is a strike; being away for more than three seconds is a strike; the third strike disqualifies you and the other side wins.
- What does a win pay?
- In a duel from the public queue: easy 40, medium 60 or hard 90 XP to the winning side, and a third of that to rating. The losing side keeps 25% as consolation. Walking away hands the other side 50%. Private rooms pay no XP or rating — they are for playing friends, not for the ladder. Duels are unlimited on every plan.
Aptitude
- What topics are covered?
- Quantitative aptitude (number system, percentages, profit and loss, ratio, averages, ages, time and work, time–speed–distance, interest, permutations and combinations, probability, mixtures, mensuration), logical reasoning (series, coding–decoding, blood relations, direction sense, syllogisms, seating and puzzles, analogies), verbal ability (synonyms and antonyms, sentence correction, fill-ins and para jumbles, reading comprehension), data interpretation (tables, charts, caselets) and programming MCQs (pseudocode, fundamentals, DSA, OS/DBMS/networks).
- Are the solutions shown?
- After an attempt — a correct answer, a wrong one, or asking to see the solution, which is recorded as an incorrect attempt. Each question has a time target, up to four hints, a worked solution and an approach note.
- How is progress tracked?
- Per topic: questions solved, attempted and your accuracy, with every question marked new, attempted or solved. Aptitude practice pays no XP and does not touch the streak — it is its own track.
- Is it free?
- Yes — unlimited on every plan, including Free.
Placement tests
- Which company patterns are included?
- 26. IT services: TCS NQT (Foundation, Foundation + Advanced, Advanced Coding), Infosys SE/DSE aptitude and SP/DSE coding, Wipro NLTH aptitude and programming, Accenture, Cognizant GenC, Capgemini, HCLTech and Tech Mahindra. Product companies: Amazon SDE online assessment, Google, Microsoft, Meta, Apple, Flipkart, Salesforce, Goldman Sachs, Deloitte, Adobe, ZS Associates, Morgan Stanley, Oracle and Zoho. Plus 3 CodeKairo practice papers, 29 in all. Each is modelled on the published pattern; none is affiliated with the company.
- Is every sitting the same paper?
- No. A pattern is a blueprint — sections, timings, marks and what each section draws from. Every sitting draws a fresh paper from the aptitude bank and the problem catalogue, so no two sittings are alike.
- How realistic is the timing?
- Sectional patterns run each section on its own clock, in order: when the time ends the next section starts, and a finished section cannot be reopened. Free-timing patterns let you move between sections until the paper's clock ends. The server owns the clock — reloading or closing the tab buys no time. Negative marking applies only where the real test has it.
- What do I get at the end?
- Score and percentage, correct, wrong and skipped, per-section scores, your weakest topics first, and a full review of every question with the answer, the worked solution and the approach. Coding problems show your code, verdict and cases passed — 10 marks each, with partial credit per test case.
Skill tests
- Which skill tests are there?
- Twelve skills, each at Basic and Intermediate level: Java, Python, JavaScript, TypeScript, C++, C and Go; Problem Solving (DSA); and SQL, OOP, Operating Systems and Computer Networks. The language tests and Problem Solving pair multiple-choice questions with coding problems judged on hidden test cases; SQL, OOP, OS and networks are multiple choice, many of them worked scenarios.
- What does passing give me?
- A verifiable credential with its own ID and a public page at codekairo.com/verify/<id>, a certificate you can download, a button that fills in LinkedIn's Licenses & certifications form, and a frame round your profile picture. 60% passes; 85% passes with distinction. A credential is valid for two years.
- Are the answers shown afterwards?
- No — not during the test and not after it. Every sitting draws a fresh paper from a private bank, and keeping the answers private is what makes a credential mean the same for everyone who holds one. Your result breaks the score down by topic, weakest first, with a link to practise each.
- Can I retake a test?
- Yes, seven days after a sitting ends, whether you passed or not. Your best result stands: a better pass raises your credential (for example to distinction) without changing its ID.
- How are the tests kept fair?
- The server keeps the clock and sections are taken in order. A test runs full screen on a laptop or desktop with the webcam checked in your browser — nothing is recorded or uploaded. Leaving the test, or the camera seeing no one, someone else or a phone, is a warning, and the third ends the sitting. Pasting is off, and a sitting that looks assisted can be reviewed and its credential revoked.
Resume ATS
- Which files can I upload?
- A PDF or DOCX up to 5 MB. Older .doc files, scanned image PDFs and password-protected PDFs are refused with a message saying what to do instead. The file is read once for its text and layout and is not kept afterwards.
- How is the ATS score calculated?
- Out of 100 across eight categories: keyword match (25), required skills (20), experience relevance (20), resume structure (10), ATS compatibility (10), achievement quality (5), education and certifications (5) and job alignment (5). Six are computed directly from the resume, the job and the file's layout; two are the AI's judgement and are capped at 25 points together. Every category shows its score, its maximum, the reason and the evidence.
- Will it tell me to add skills I don't have?
- No. A missing skill is reported as asked for by the job and not shown in the resume — add it only if it's true. AI rewrites keep your facts: a number the resume doesn't contain becomes [add figure] for you to fill in, and a technology the resume never mentions is dropped or flagged. Nothing changes until you accept it.
- Do I need to sign up to check my resume?
- No. Upload a PDF or DOCX on the page, optionally name the role or paste the job description, and the ATS score with every reason, the missing keywords and the layout risks appears at once. Neither the file nor the report is stored. A free account adds the AI review, bullet rewrites, an editor that re-scores as you fix, versions and a PDF or DOCX export.
- Is it free?
- Yes. The check is free without an account, and the full analyzer is free on every plan. The limits are a dozen checks an hour from one network without an account, and twenty uploads and sixty AI requests an hour per account. You can export the result as a PDF or DOCX at any time.
Pricing
- Is everything free right now?
- Yes. Until 1 January 2027 everything on CodeKairo is free for every account: every plan's limits are lifted — unlimited mock interviews, 30-minute voice rounds and unlimited bug hunts — so no plan is needed until then. The plans on this page are what each will cost from 1 January 2027; a plan bought before that keeps its dates and resumes as bought.
- Is there a free plan?
- Yes, and it is free forever — no trial period, no card. DSA problems, bug hunts, SQL, the roadmap, study plans, CS notes, aptitude, the AI tutor, duels and pair rooms are unlimited; the metered features are a placement mock test 1 every 10 days, a resume analysis 1 a week, a written AI interview 1 a week, a voice AI interview 1 every 10 days and a company simulation 1 every 2 weeks, from 1 January 2027 — until then every limit is lifted.
- What does Pro cost?
- ₹149 for 1 month, ₹399 for 3 months, ₹999 for 12 months — ₹83 a month on the yearly plan. Or buy a pass: the Sprint Pass, ₹99 for 7 days, and the Placement Season Pass, ₹699 for 6 months. Every option gives the same Pro access for its time.
- What do I get with Pro?
- The Free plan is free forever, with no card: unlimited DSA problems, bug hunts, SQL, the roadmap, study plans, notes, the AI tutor, duels and pair rooms, plus resume analyses (1 a week), placement mock tests (1 every 10 days), written AI interviews (1 a week), voice AI interviews (1 every 10 days), company simulations (1 every 2 weeks). Pro raises those to resume analyses 1 a day, placement mock tests 1 every 2 days, written AI interviews unlimited, voice AI interviews 8 a month, company simulations 5 a month, and adds Intermediate skill tests, 20- and 30-minute voice rounds and the resume download. Pro costs ₹149 for 1 month, ₹399 for 3 months, ₹999 for 12 months (₹83 a month on the year), or buy a pass: Sprint Pass ₹99 for 7 days, Placement Season Pass ₹699 for 6 months. Pro Max, for heavier use, has resume analyses unlimited, placement mock tests unlimited, written AI interviews unlimited, voice AI interviews 12 a month, company simulations 10 a month, plus 50 bonus credits a month, for ₹399 for 1 month, ₹999 for 3 months, ₹2,999 for 12 months. Credit packs (₹99 for 100, ₹249 for 300, ₹499 for 700) pay for one more use after an allowance is spent. Every purchase is a one-time payment in rupees, GST included — nothing renews automatically.
- What are credits?
- Credits pay for one more use of a limited feature once its allowance is used — only when you choose to spend them. Packs: ₹99 for 100 credits, ₹249 for 300 credits, ₹499 for 700 credits. They never expire, and they work on Free and on Pro.
- Does a plan renew automatically?
- No. Every purchase is a one-time payment — by UPI, card or net banking — and runs for the time you bought. Buying again while Pro is running adds the new time to the end, so nothing is lost.
- How are payments handled?
- Through Cashfree, in Indian rupees. Card, UPI and bank details go to Cashfree directly and never reach CodeKairo; the site records the plan, the order reference, the amount and the payment status.
Community
- What can I post?
- A status with an optional topic chip (Shipping, Debugging, Learning, Idea, Milestone), a question — optionally pinned to a problem or bug hunt, whose asker can later accept one answer — a poll with two to four options, or an achievement share from a success screen. Posts run to 2,000 characters, take up to 8 #tags and 5 @mentions, and render code in ``` fences as a block.
- Are shared wins real?
- Yes. An achievement share is verified against the judge's records before it posts — a solved problem, a fixed bug hunt, an opened roadmap chest — so a share is always something the author actually did.
- Who sees my posts?
- Your choice per post: anyone on CodeKairo, your followers, or only you. A followers-only or private post is hidden from everyone else, including by direct link. The public feed can be read without an account; posting, respecting, commenting, saving and following need a free one.
- How is the For you feed ordered?
- By recency with a 24-hour half-life, engagement, your interest in the post's tags, whether you follow or are followed by the author, and a boost for shared wins — never more than two consecutive posts by one author. Following is strictly chronological, and older posts fill in below the ranked window.
Tournaments
- Can my college host a coding competition on CodeKairo?
- Yes, on CodeKairo Battles (battles.codekairo.com). Create an organization for your college, club or company, have it verified by CodeKairo, and run a 1v1 knockout or an ICPC-style team contest on this site's problem catalogue and judge, in all 13 languages. Entry can be limited by email domain, invite code or your approval. Hosting is free.
- Do tournament solves count on my CodeKairo profile?
- Yes. An accepted submission in a tournament is an ordinary CodeKairo submission: it counts toward your solved problems, heatmap, streak and roadmap stages and pays XP the first time you solve that problem. The problem is marked as solved in a tournament, and your profile lists every tournament with where you finished.
- Do I need a separate account for CodeKairo Battles?
- No. Battles uses your CodeKairo account; sign in there with email, Google or GitHub, or arrive already signed in from this site.