Rakuten Group, headquartered in Tokyo, runs Rakuten Ichiba, one of Japan's largest online marketplaces, alongside a mobile network, card, bank, travel and e-book businesses. English has been its official internal language since 2012, which makes it one of the more accessible Japanese employers for international engineers, though some candidates report a check of their Japanese. This page covers what Rakuten builds and who it hires, the process candidates commonly report, the technical depth the teams care about, representative problem types, what interviewers score, and a three-week prep plan.
What Rakuten builds and who it hires
Rakuten's engineering spans many businesses. Ichiba back-end postings ask for Java with Spring Boot, with Kotlin, Kubernetes, gRPC, GraphQL, Redis and Elasticsearch also listed, and a Kobo e-book team works in Java and Spring Boot on Oracle and PostgreSQL. Rakuten Mobile launched commercial service in April 2020 on what Rakuten described as the world's first fully virtualized, cloud-native mobile network, and Rakuten Symphony now sells that Open RAN approach to other operators. Other teams build Rakuten Travel, payments and the points program, advertising and data platforms.
- Back-end engineers: Ichiba marketplace, storefront and back-office services in Java and Spring Boot.
- Telecom and cloud engineers: Rakuten Mobile and Symphony's cloud-native network platform.
- Front-end and mobile engineers: shopping, travel and fintech apps.
- Data and machine learning engineers: search, recommendations, advertising and points.
What the process tends to look like
| Stage | What happens | How to prepare |
|---|---|---|
| Recruiter or HR screen | Background, motivation, visa and language | Be honest about your Japanese level |
| Online coding test | Candidates commonly describe an online test taken at home, with several reports naming Codility | Timed easy-to-medium problems with hidden edge cases |
| Technical interviews | Two or three video or in-person interviews, often with a more senior interviewer at each step, covering coding, your projects and design | Java depth and one marketplace design |
| Final interview | A senior manager or department head on fit and motivation | Why Rakuten and why Japan |
Processes differ by team, level and office and change over time, so treat this as the common shape candidates report and confirm the specifics with your recruiter.
Marketplace systems, Java and working in Japan
A marketplace of merchants. Ichiba is a mall of independent merchants rather than a single retailer, so design questions can involve shop-controlled storefronts and listings, search across many shops, and points earned and spent across Rakuten services.
Java and Spring. Back-end roles expect solid Java: collections, concurrency, Spring Boot, transactions and database design, and several postings mention Kubernetes. Our Java interview questions and Kubernetes interview questions help.
The coding test. Candidates describe the online test as the main early filter. Codility-style tests score correctness and performance on hidden cases, so test empty, single-element and very large inputs; our Codility test guide explains the format.
Language and location. English is Rakuten's official language, but some recent candidates report being asked about their Japanese, and team language varies. Our guide to interviewing in Japan covers local interview norms.
Representative problem types
These are the kinds of problems candidates describe, not a leaked question list. Practice the category, not the exact question.
- Easy and medium array, string and hash map problems with hidden performance tests.
- Design product search across many merchants' storefronts.
- Design a points system that is earned and spent across services.
- Design a campaign page that survives a large traffic spike.
- Rank products in a category by relevance and sales.
- Explain transaction isolation and a deadlock in a relational database.
- Implement an LRU cache or a rate limiter in Java.
What interviewers score
- Working code: a solution that runs, handles edge cases and is readable by the next engineer.
- Practical judgment: the trade-offs you name and the simplest design that meets the requirement.
- Product sense: understanding who the user is and what failure looks like for them.
- Ownership: examples where you shipped, measured and fixed things yourself.
The behavioral side
Technical rounds decide most outcomes, but every Rakuten loop also asks about how you work. Prepare a short story for each of these, with a result and what you learned:
- Something you shipped end to end. Cover the user problem, your decisions, what you measured and what you would change.
- A disagreement with a teammate. Show how you made the decision on evidence and kept the relationship.
- Why this company? Connect its product and engineering problems to the work you want to do next.
Structures and sample answers for the common questions are in our software engineer behavioral answers guide.
A three-week prep plan
- Week 1: Codility-style tests: ten timed easy-to-medium problems, each with your own edge-case and large-input tests; our Codility test guide has the scoring details.
- Week 2: Java and design: Spring Boot, transactions, concurrency and Kubernetes basics, then a merchant marketplace design and a points ledger design, each done aloud.
- Week 3: interviews: rehearse project walkthroughs for increasingly senior interviewers, prepare a clear answer to why Rakuten and why Japan, and do two mock interviews.
For practice lists, use LeetCode company-tagged questions; for design rounds, read system design building blocks; and compare Asian e-commerce loops at Shopee and Coupang.
Where CoPilot Interview fits
Most of a Rakuten loop is spoken: you explain an approach, defend a trade-off and talk through your past work. CoPilot Interview is an AI interview assistant whose free AI mock interview builds technical and behavioral questions from your résumé and the job description, reads them aloud and scores each spoken answer out of ten, so you can rehearse the explanation as well as the code. The free plan gives 15 minutes a day of live help in sessions of up to 15 minutes, with AI mock interviews included. Online assessments and many coding rounds forbid outside help, so practice beforehand and follow your employer's rules on the day.
Disclosure: CoPilot Interview is our product, so weigh what we say about it accordingly.
Frequently asked questions
What programming language should I use in a Rakuten interview?
Java is the most common back-end language, with Kotlin in some teams. Online tests usually let you choose; use Java if the role lists it and you are fluent.
Does Rakuten send an online assessment?
Most candidates report an online coding test early in the process, with several naming Codility. The rounds after it vary by business unit and level, so ask your recruiter.
Do I need to speak Japanese to work at Rakuten?
Not always. Rakuten made English its official internal language in 2012, and many engineering teams work in English. Some candidates still report a Japanese check, and domestic or customer-facing teams may need it, so read the posting and ask your recruiter.
How should I prepare for Rakuten coding questions?
Practice practical problems under time limits, build small features against an API in your interview language, and prepare one system design in Rakuten's domain. Explain every solution out loud, because follow-up questions about trade-offs matter as much as the first answer.
Can I use AI tools in a Rakuten interview?
Only if the instructions you receive say so. Online assessments and live coding rounds generally forbid outside help, and some companies now state their AI policy in the invitation. Use AI to practice beforehand, and follow your employer's rules.
Practice this interview before the real one
The AI mock interview builds questions from your resume and the job description, reads them aloud and scores each spoken answer out of 10. Included on the free plan.
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