101OneNoughtOne

Practice

Build, debug and explain your way to stronger skills.
All practice problemsCoding, design and hands-on challenges.Repository CodingHands-onFix bugs and build in a real codebase.Code ReviewHands-onFind risks and explain your verdict.Data structures & algorithmsCore patterns to advanced algorithms.Machine learningImplement ML and numerical methods.SQL & databasesQueries, data and analytical problems.HLD system designScalable architecture and tradeoffs.LLD system designObjects, interfaces and behavior.GATE papersBranch-wise previous year papers and worked solutions.AptitudeAptitude topics and exam practice.AI interview prepRehearse interviews with an AI tutor.Online compilerWrite and run code in your browser.

Learn

Follow a path, explore a concept or study at your own pace.
Learning pathsConnect lessons, visualizers and practical challenges.Algorithm visualizersStep through algorithms and see how they work.ReadingRead books, notes and research papers with AI.Daily current affairsUnderstand the news, save notes and revise the brief.Data structures & algorithmsLearn the foundations of efficient problem solving.Machine learningBuild mathematical intuition and explore ML concepts.SQL & databasesUnderstand data models, queries and transactions.System designStudy architecture, distributed systems and object design.
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ONENOUGHTONE / MEMBERSHIP

Invest in your next step.

A useful free account. Affordable plans when you want more.
Choose the space that fits what you're working towards.

USD prices exclude applicable taxes; your final total is shown at checkout. Annual plans are paid upfront.

A place to begin

Free

Start learning. Build a daily habit.

$0/ forever

No card needed. Supported by ads.

Create free account
  • Full core lessons after sign-up
  • Jobs, resume tools and study essentials
  • 250 AI credits / month
  • Sample coding, ML and repo compute
See the included limits

Build your study routine

Study

For exams, aptitude and everyday study.

$19/ year

$36 in 12 monthly payments Save 47%

Works out to $1.58 / month

  • Current-affairs archive
  • 600 Aptitude & PYQ tests / month
  • A larger book and study workspace
  • Ad-free learning
  • 1,000 AI credits / month

Build your career

Career

For coding, engineering and your next role.

$49/ year

$84 in 12 monthly payments Save 42%

Works out to $4.08 / month

  • Complete technical editorials and solutions
  • Full visualizer traces
  • 30 repository coding sessions / month
  • 100 code reviews / month
  • More coding and ML practice
  • Ad-free learning
  • 3,000 AI credits / month

The complete combination

All Access

Study + Career, together in one plan.

$69/ year

$120 in 12 monthly payments Save 43%

Works out to $5.75 / month

  • Everything in Study and Career
  • Our largest included AI allowance
  • More room for books, notes and bookmarks
  • Ad-free learning
  • 5,000 AI credits / month

Every account includes core learning, progress, jobs and community. Paid plans add content, capacity and an ad-free experience. Compare the details below.

MORE TIME WITH ONO

Keep the conversation going.

Top up any verified account, including Free. Use credits across AI tools. Valid for 12 months.

5,000 AI credits$4.99 · one-time

THE DETAILS, CLEARLY

Know what's included.

Choose for your goals. Keep your existing notes, books and history if your plan changes.

Hover, focus or tap a ? for details.

Monthly limits and capabilities for each personal plan
What you getFreeStudyCareerAll Access
Lessons & learning pathsIncludedIncludedIncludedIncluded
Aptitude & PYQ practiceIncludedIncludedIncludedIncluded
Coding & ML problemsIncludedIncludedIncludedIncluded
Review & design practiceIncludedIncludedIncludedIncluded
Design solutionsPreviewPreviewIncludedIncluded
Visualizer walkthroughsPreviewPreviewIncludedIncluded
Community & progressIncludedIncludedIncludedIncluded
Practice insightsIncludedIncludedIncludedIncluded
Ad-free accessAds on FreeIncludedIncludedIncluded
Editorials & solutionsPreviewPreviewIncludedIncluded
Current affairsRecent 7 daysIncludedRecent 7 daysIncluded
AI credits / month2501,0003,0005,000
Ask OnoUses AI creditsUses AI creditsUses AI creditsUses AI credits
AI tutor & mock interviewsUses AI creditsUses AI creditsUses AI creditsUses AI credits
Coding runs / day3060100150
Coding runs / month3006001,5003,000
ML runs / day22515
ML runs / month101060500
Repo coding / month113060
Code reviews / month55100200
Code visualizer / month20303001,000
Aptitude & PYQ / month1060010600
Jobs & Top MatchesIncludedIncludedIncludedIncluded
Application autofillIncludedIncludedIncludedIncluded
Job automationIncludedIncludedIncludedIncluded
AI application helpUses AI creditsUses AI creditsUses AI creditsUses AI credits
Application tracker2505002,0002,000
Saved resumes352525
Books3251025
PDF reading & highlightsIncludedIncludedIncludedIncluded
Book storage100 MiB500 MiB500 MiB1 GiB
Notes1001,0001,0002,000
Bookmarks2502,5002,5005,000

Shared capacity, short-term rate limits and per-session safety timeouts apply to every plan. AI tools use your credits. Extension features work on supported employer forms and follow your approved automation settings.

GROW TOGETHER

For campuses.
For hiring teams.

Agree seats, candidates and usage budgets before you launch. Your students and candidates get the access your organization funds.

Discuss a plan

A FEW THINGS TO KNOW

Good questions.
Clear answers.

What can I do for free?+

Create an account for full core lessons and learning paths, practice problems, jobs, resume tools, notes, bookmarks and progress. Free includes ads, 250 AI credits each month and sample compute allowances. Visitors can browse catalogues and public samples.

How do AI credits work?+

Credits pay for Ask Ono, tutoring, feedback, resume help and other AI tools. Ono is OneNoughtOne’s AI learning companion. Long prompts, outputs and reasoning can use more credits. Paid credits refresh on your monthly subscription anniversary, including on annual plans; Free credits refresh each UTC calendar month. Included credits do not roll over. When you change plans, credits already issued in the current window count towards your new allowance. Purchased top-ups expire after 12 months. A top-up adds AI credits; content, compute and ads follow your plan.

What counts as a run, test or session?+

Clicking Run, Submit or running code in the online compiler counts once towards your shared coding limit for DSA and SQL. Machine-learning runs and submissions have a separate limit. Starting an Aptitude & PYQ test or submitting a code review counts once; repository coding counts when a workspace is prepared. Each request has a safety timeout. Repository sessions last up to 30 minutes on Free, 30 on Study, 60 on Career and 60 on All Access, starting when the workspace first starts. Practice limits reset in UTC. Execution uses CPUs; GPUs are not included.

Are jobs and the browser extension included?+

Every account gets job search, profile-based Top Matches, application tracking and the Chrome extension for supported employer forms. Autofill and automation use answers you have approved, with safety and pacing limits. AI-enhanced matching, answer drafting and document polishing use your AI credits. Career and All Access give you more credits and a larger career workspace.

Can I change or cancel a plan?+

Manage your subscription from Billing. Canceling keeps access through the paid period. Contact support to change a plan while you have active access, so you do not pay for overlapping subscriptions.

Why does annual billing cost less?+

Annual payment helps us plan capacity and reduces payment overhead. The crossed-out comparison is exactly 12 monthly payments for the same plan. The annual total is charged upfront; AI credits are still issued monthly.

What about campuses and hiring teams?+

We arrange contracts directly, with agreed seats or candidate limits and prepaid AI and compute budgets. Invited candidates do not need a personal subscription. Contact us to discuss your expected usage.

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101OneNoughtOne

Built one step
at a time.

Learn a concept. Solve a problem. Build something real. Your next chapter starts here.

Find your next challenge Explore the curriculum

Learn

  • DSA
  • HLD System Design
  • LLD System Design
  • Machine Learning
  • SQL & Databases
  • Practice Problems
  • Full Curriculum
  • Aptitude
  • GATE papers & solutions

Resources

  • Algorithm Visualizers
  • Computer Networks
  • Operating Systems
  • Interview Prep
  • Learning Roadmap
  • Database Management
  • Repository Coding
  • Code Review

Company

  • Pricing
  • Contact
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  • Job Assistant
  • For Hiring Teams
  • For Institutions

Legal

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Online Compilers

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