What the round is
The architecture round — also known as system design, or distributed systems design — is an hour in which the candidate designs a system from a verbal description. T-Bank publishes the round’s brief word for word (in Russian): in an hour, “formalize the problem, design the system’s API, estimate the load and the required capacity, design the data models and data flows.” That list is the plan of the round.
Who gets it
The round is tied to seniority, and that is perhaps the most important thing to know about it: the very fact that it has been scheduled indicates which grade the candidate is being considered for. The companies word it differently, but the meaning is the same.
Yandex holds the architecture round “only for candidates with commercial experience designing high-load distributed systems” and allots an hour and a half to it — an hour for the solution and half an hour for logistics. Avito’s hiring playbook calls the design round optional and states its purpose outright: “the main differentiator for reaching level E5,” that is, one of the steps on the company’s internal grade ladder. At T-Bank the round is part of the standard loop for backend, Java, Go, Python, Scala, C++, .NET and team leads — and is absent from the JavaScript, QA and SRE pages.
How it is structured
An hour at an online whiteboard: T-Bank names Unidraw and Sketchboard and suggests getting used to the board’s interface in advance, before the interview. The problem is given verbally and deliberately incomplete. Avito has split its round into three phases, and the first is not about architecture at all: 5–10 minutes go to understanding the problem and defining the system’s boundaries, about 20 minutes to high-level design and load calculation, and about 30 minutes to details — technologies, client–server interaction, optimizations, metrics.
Half the time goes to details, but they can only be reached with a coherent overall picture by the twentieth minute. A candidate stuck on clarifying requirements never gets to that half of the round.
Load estimation
This is the step most often skipped as a formality. Yet it is part of the official requirements of both companies that publish such requirements. T-Bank phrases it as “estimate the load and the required capacity.” Yandex as “estimate the system’s performance and the amount of computing resources needed for it to run normally.” At Ozon, candidates describe direct questions of the same kind: “calculate in numbers the maximum disk write speed in this system.”
The point of the step is that architectural decisions grow out of the numbers. In a candidate’s report from February 2026, Yandex’s architecture round began with designing a photo-sharing service. The candidate assumed 500 million accounts; the interviewer raised the estimate to two billion. With one post every ten days, that gives around 200 million posts a day. From there the arithmetic is done in one’s head. 200 million a day is about 2,300 writes per second on average and three times that at peak, with reads an order of magnitude higher: so the feed will have to be assembled in advance rather than queried across subscriptions when it is opened. With an average photo of two megabytes, the daily total comes to around 400 terabytes: so files are not stored in the database — object storage and a CDN are needed. Both architectural decisions came out of two divisions done in one’s head.
Precision is not required here; what is required is the order of magnitude and assumptions stated out loud. A Yandex interviewer puts it directly: if the inputs are insufficient, “you can and should put forward reasoned hypotheses.”
What gets graded
Knowledge of fashionable technologies comes last. Avito lists its criteria openly: the ability to build a working architecture from the gathered requirements, to “weigh the pros and cons of the chosen solutions,” and to “identify and mitigate long-term risks.” The same source names the typical failure: the candidate “gets the assignment and doesn’t know where to start the design.”
The candidate leads the conversation in this round, and that too is stated explicitly. A write-up of Yandex’s architecture rounds (in Russian) says: “solving the assignment will involve a lot of talking, but we expect the candidate to be the main participant in the conversation.” A candidate who stays silent and waits for the interviewer to drive the discussion is marked down for it.
How directly this converts into a grade is shown by a public write-up from T-Bank (in Russian), which the company itself lists in its preparation materials. It concerns a candidate who designed the system only for the scenario in which everything goes as planned — what the industry calls the happy path. The wording leaves no room for interpretation: “if the candidate did nothing beyond the happy path, and from then on the interview looks like questioning the candidate with a pile of detailed questions about parts of the system, which the candidate answers, then that is already Junior level.” If the candidate finds and solves the problems on their own, and the interviewer only needs to highlight them, that is a bid for Middle. The same write-up lists readability as a separate criterion: if a diagram cannot be read without its author, that is a bad sign.
Problems by company
| Company | Format | What is asked | Who gets it |
|---|---|---|---|
| Yandex | Dedicated round, 1.5 hours: an hour for the solution, half an hour for logistics | Designing a photo-sharing service with a subscription feed; the scale is settled in the dialogue | Only candidates with commercial experience designing high-load distributed systems |
| T-Bank | 60 minutes, Unidraw or Sketchboard online whiteboard | Formalize the problem, design the API, estimate the load and capacity, design the data models and data flows | Backend, Java, Go, Python, Scala, C++, .NET, team leads. The round does not appear on the JavaScript, QA and SRE pages |
| Avito | Three phases: 5–10 minutes of questions, ~20 on high-level design, ~30 on details | “Let’s design Avito”, a widget builder on a JS framework, a backend for a notification service, PaaS | The round is optional and described as the main condition for moving up to level E5 |
| Ozon | Dedicated round; ends with a short conversation about team fit | The architecture of a large product; according to candidate reports, “they gave me Instagram,” with an emphasis on load calculations | — |
| VK | A design round appears in the track | A chat in which a streamer talks to subscribers; a news service with a top list | For mobile roles the company notes that the round is not suited to beginning developers |
What the companies themselves advise
The companies publish their own preparation materials for this round, and their lists overlap. Yandex and T-Bank both recommend the same source: System Design Primer. Yandex points to its appendix on the “numbers you definitely need to know” — the very orders of magnitude from which load is calculated. T-Bank adds Architectural Katas, its own article on preparing for the round, and recordings of two public system design interviews, noting that they resemble how the company conducts its interviews: they cover designing YouTube and a hotel booking system.
For books, both companies name roughly the same ones: Kleppmann’s “Designing Data-Intensive Applications”; Tanenbaum on distributed systems; Google’s SRE book. Yandex’s practical advice is the simplest: take a large sheet of paper or a whiteboard and try to design any well-known complex system.
AI in the round
Russian companies publish no rule specifically for the architecture round. At Yandex, the ban on Copilot, ChatGPT and Cursor is written into the coding-round sections; the description of the architecture round contains no rules at all on AI, the camera or screen sharing. T-Bank states a general rule for all technical rounds: “Try not to peek. When a candidate uses a phone, neural networks or a search engine, it shows.”
No company has called the round AI-proof, and claiming so would be an exaggeration. It is, however, set up so that prompting helps little: the conversation happens live at the whiteboard, the interviewer adjusts the difficulty on the fly depending on the answers, and the criteria include the readability of the diagram and the ability to lead the conversation. A neural network can draw the diagram. Answers to “why exactly this trade-off” and “what happens if a node goes down” the candidate will have to give themselves.
On the technical side — what does and doesn’t end up in a screen share — there is a separate breakdown: what is visible when sharing your screen.
FAQ
Who gets system design — only seniors?
The round is tied to seniority, but in different ways. Yandex holds the architecture round only with candidates who have commercial experience designing high-load distributed systems. At Avito it is optional and is explicitly called “the main differentiator for reaching level E5.” At T-Bank the system design round is part of the standard loop for backend, Java, Go, Python, Scala, C++, .NET and team leads — but it does not appear on the JavaScript, QA and SRE pages.
What should I do if the problem is vague?
It is vague on purpose, and that is exactly what the first phase of the round is about. Avito allots 5–10 minutes to understanding the problem and defining the system’s boundaries, and expects clarifying questions about functionality, audience and deadlines. An Avito interviewer names the typical failure plainly: the candidate “gets the assignment and doesn’t know where to start the design.” If the inputs are insufficient, a Yandex interviewer advises “putting forward reasoned hypotheses” — that is, stating an assumption out loud and moving on.
Do I need to know exact load figures?
What you need is the order of magnitude and assumptions stated out loud. Load estimation is an official requirement at both companies: T-Bank phrases it as “estimate the load and the required capacity,” Yandex as “estimate the system’s performance and the amount of computing resources needed for it to run normally.” At Ozon, candidates describe questions such as “calculate in numbers the maximum disk write speed in this system.”
Where do I draw the diagram?
On an online whiteboard, and it is worth getting used to it in advance. T-Bank names Unidraw and Sketchboard and separately suggests practicing on the board before the interview; for mobile roles the same pages name Excalidraw and Miro. The readability of the diagram is a criterion in its own right: T-Bank’s public write-up says that if a diagram cannot be read without its author, that is a bad sign.
Do I have to name specific technologies?
Yes, but each name should come with a justification and an alternative. Among its criteria Avito lists the ability to “weigh the pros and cons of the chosen solutions” and to “identify and mitigate long-term risks.” “Let’s use Kafka” with no answer to why not a queue in the database reads as a memorized list, not a decision.
Can I use AI in the architecture round?
Russian companies publish no rule specifically for the architecture round. At Yandex, the ban on Copilot, ChatGPT and Cursor is written into the coding-round sections, not the architecture one. T-Bank states a general rule for all IT rounds: “Try not to peek. When a candidate uses a phone, neural networks or a search engine, it shows.” In practice the round does not lend itself well to prompting: it is a dialogue at the whiteboard, the interviewer changes the difficulty on the fly, and the grading includes the readability of the diagram and the ability to lead the conversation.
Sources
- Yandex: the backend developer interview (in Russian) — the architecture round: the experience requirement, an hour and a half, grading criteria including the calculation of computing resources.
- Avito’s hiring playbook (in Russian) — the design round as the condition for moving up to level E5, sample problems.
- “Take the initiative”: preparing for the System Design Interview (in Russian) — August 2023, an Avito interviewer: the three phases of the round, criteria, typical mistakes.
- Interviews at Yandex and VK, backend, February 2026 (in Russian) — a candidate’s diary: architecture problems and how the two-billion-account scale emerged in the dialogue.
- A report on interviews at Ozon, T-Bank and other companies (in Russian) — July 2025: Ozon’s architecture round and load-estimation questions.
The other stages of the funnel are covered in the overview of developer interview stages. Neighboring rounds: algorithms and live coding.