Low-level designLast seen Sep 2026
Design a Cross-Exchange Arbitrage Engine
Maintain valid, fresh cross-exchange quotes, emit each executable price inversion once, and track paired orders through independent execution outcomes.
Open practiceJane Street interview practice
Jane Street online assessment and coding practice Start with verified evidence.
Practice from 11 Jane Street-tagged public coding problems, organized only by the stage, topic, difficulty, and recency metadata FastPrep can verify. The broader public catalog also includes 1 low-level-design exercise.
- Catalog
- 12 public practice assets (11 coding)
- Start here
- Use the stage named in your invitation
- Evidence
- OA · Phone · Onsite metadata, shown in context
OA practice path
Online Assessment
Build a timed implementation rhythm from prompt to edge cases. Problems are ranked by repeated public catalog sightings.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
JSJane Street | Cheating CodemakerArrayString | Medium | 1 public reportLast reported Mar 2026 | Practice |
JSJane Street | Transform StringStringStack | Medium | 1 public reportLast reported Jul 2024 | Practice |
Phone practice path
Phone Screen
Practice solving while explaining assumptions, tradeoffs, and complexity. Problems are ranked by repeated public catalog sightings.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
JSJane Street | Instrument Stack Language JumpsArrayPrefix Sum | Medium | 3 public reportsLast reported Oct 2026 | Practice |
JSJane Street | Run a Stack Language InterpreterStackSimulation | Medium | 2 public reportsLast reported Oct 2026 | Practice |
JSJane Street | Positive-Integer Expression EvaluationParsingRecursion | Medium | 1 public reportLast reported Oct 2026 | Practice |
Onsite practice path
Onsite
Practice complete solutions and defend the choices behind them. Problems are ranked by repeated public catalog sightings.
6 Jane Street-tagged Onsite problems available.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
JSJane Street | Code Editor FoldingStackString | Medium | 1 public reportLast reported Oct 2026 | Practice |
JSJane Street | Exact-Sixty Dice Game ValueArrayMath | Easy | 1 public reportLast reported Oct 2026 | Practice |
JSJane Street | Expected Value of Modified DiceArrayMath | Medium | 1 public reportLast reported Oct 2026 | Practice |
JSJane Street | Spaceship Equipment LoadoutArrayBacktracking | Medium | 1 public reportLast reported Oct 2026 | Practice |
JSJane Street | Two-Tower Strategy GameBacktrackingSimulation | Hard | 1 public reportLast reported Oct 2026 | Practice |
JSJane Street | Wizard Scroll Allocation StrategyArrayBacktracking | Medium | 1 public reportLast reported Oct 2026 | Practice |
01 · Preparation plan
Turn duplicate-aware simulation and stack cancellation into a deliberate practice loop.
Jane Street's two OA records support a deliberately narrow page: count exact and misplaced code colors without double use, then prove why local pair cancellation can be processed with a stack. Catalog labels guide practice but do not promise a current or universal hiring loop. This is a suggested practice sequence, not the employer's interview process. Your invitation and recruiter guidance remain the source of truth.
- 01
Practice Cheating Codemaker
Use Cheating Codemaker to rehearse duplicate-aware code feedback. Keep the exercise's published contract separate from assumptions about Jane Street's current interview process.
- Restate the exact input, output, and constraints for duplicate-aware code feedback.
- Explain the data structure and complexity before completing the implementation.
- Test a boundary case, a repeated-value case, and the smallest valid input.
- 02
Practice Transform String
Use Transform String to rehearse adjacent-pair cancellation with a stack. Keep the exercise's published contract separate from assumptions about Jane Street's current interview process.
- Restate the exact input, output, and constraints for adjacent-pair cancellation with a stack.
- Explain the data structure and complexity before completing the implementation.
- Test a boundary case, a repeated-value case, and the smallest valid input.
- 03
Connect duplicate-aware code feedback with adjacent-pair cancellation with a stack
Finish the Jane Street study block by comparing Cheating Codemaker with Transform String. Explain what changes between implementation-level correctness and the broader engineering tradeoff.
- Name the invariant shared by both exercises.
- Contrast their state, scale, and failure assumptions.
- Choose one follow-up and defend the next test you would run.
02 · Broader technical practice
Practice beyond standalone coding questions.
These public Jane Street-tagged exercises cover additional technical formats. They are included only when a verified catalog record and a crawlable practice page both exist.
03 · Evidence boundary
What “Jane Street interview questions” means here.
It means practicing transferable implementation, testing, and technical reasoning with public catalog assets FastPrep tags to Jane Street. It does not mean FastPrep has access to the company's assessments or any private interview bank.
Repeated public sightings and last-reported dates can help you prioritize practice, but they cannot predict the questions, format, or platform in a specific interview.
- Only Jane Street-tagged FastPrep catalog problems appear above.
- Stage labels and report dates remain visible as context.
- No official, private, leaked, or proprietary questions are claimed.
04 · Plain answers
Jane Street interview practice questions, answered plainly.
This page owns technical-practice intent for Jane Street. Hiring activity, timelines, and market signals remain on the separate hiring-insights page.
01What evidence supports this Jane Street interview practice page?
The launch review verified 2 coding exercises (2 total public practice items). The strongest reviewed themes are duplicate-aware code feedback, adjacent-pair cancellation with a stack. Counts and report labels can change, so use this as a focused practice library and follow your own invitation for the current format, timing, and permitted tools.
02Is FastPrep affiliated with Jane Street?
No. FastPrep is an independent interview-preparation product and is not affiliated with Jane Street. The page uses FastPrep's public practice catalog and does not claim official, private, leaked, or proprietary employer questions.
03How are Jane Street problems assigned to interview stages?
Stage labels come from FastPrep's public problem metadata. A problem can carry more than one reported stage, and hiring processes can change by role, level, location, and date. Treat the labels as preparation context, not a guarantee.
04Which Jane Street interview stage should I practice first?
Start with the stage named in your invitation or recruiter message. If no stage is known, use the largest available set to build general problem-solving fluency, then rehearse explanation and testing separately.
05Does this page predict the Jane Street interview process?
No. Public catalog counts, stage tags, and last-reported dates can help prioritize practice, but they cannot predict a specific interview's questions, sequence, timing, or platform.
Your next stage, made concrete
Pick a problem. Solve it end to end.
Start with the stage named in your invitation, then use public evidence as context—not as a promise of what you will be asked.
Open the practice set