Get Hired / Interview / Technical Interview 26 chapters · 1 free
Backend Technical Interview Questions The largest section here, because this is where offers are won and lost. Not trivia definitions — the second and third questions, the ones that find out whether you have actually run this in production.
16 Before We Begin Free Welcome to technical interview section. Let's talk what you can find here 17 Try to talk about the problems of the system instead of the advantages General advice: always mention the pitfalls, trade-offs, and limitations of the system. Not just the problems it solves — the problems it creates. Some… 18 What is Concurrency Yes, I know that you know what concurrency is. But knowing it and being able to explain it in a way that impresses an interviewer are two different… 19 ACID ACID in one big speculation. Let me explain. 20 Isolation levels And Common Sense Dirty read, read committed, dirty write, write skew, repeatable read, SSI, MVCC, two-phase locking Ugh, this topic is overloaded with terminology. Let's… 21 Isolation levels And The Twist Three isolation levels is what we have seen already: No isolation — chaos, everyone reads and writes whatever, wherever, whenever. Full isolation — serial… 22 Optimistic and Pessimistic locks Ultra popular question. Basically, the question is always somewhere around: "You have 2 users updating one account simultaneously. How do you make this… 23 A Bit More About Locks Couple of cool things you can put your lock to 24 Indexes, Part 1: Main Types Index is very popular topic which for sure will appear on your interview. Without going into much detail, I have gathered information, which you need to… 25 Indexes, Part 2: Composite index Composite Indexes and the Leftmost-Prefix Rule Say you create an index on . That's not two indexes glued together — it's one sorted structure, sorted by… 26 Indexes, Part 3: Clustered vs Non-Clustered Honestly, nobody has ever asked me "What's the difference between a clustered and non-clustered index?" But it's an important definition to know for… 27 Indexes, Part 4: Geospatial 28 SQL traps, Part 1 Question This is a real question I have received in an interview. Let me copy paste it here and let's talk about SQL traps. 29 SQL traps, Part 2 Joins The next overall feature/problem of SQL is joins. It was one of the reasons NoSQL emerged. Because imagine if you have quadzillions of pieces of… 30 SQL traps, Part 3 Other SQL traps which are worth mentioning 31 How to improve a slow database This is a super frequent question. Let's go through the main things you can do to improve database speed with some show-off methods. 32 Problems with ORMs There is a big probability that they will ask you about JPA and Hibernate if this is Java or another ORM for other language. I will not teach you the… 33 Troubles with distributed systems Modern software engineering is all about distributed systems. Basically, when a program works on more than one computer. It means that the conversation on… 34 Monolith vs Microservices Intro When this topic comes up, most candidates start something like: Monolith bad 👎 Microservices good 👍 I'm not going to write another "Differences… 35 gRPC vs HTTP There are two main styles in modern software engineering for how one application calls another: REST or RPC (most commonly gRPC). Both typically run over… 36 RabbitMQ and Kafka When the interviewer starts talking about RabbitMQ and Kafka, you can always pick the one you know better. Normally, I honestly say something like: I know… 37 How do you deal with traffic Here's the thing — everyone gives the same answer to this question. Autoscaling, caching, load testing, blah blah blah. If you just recite the checklist,… 38 Kubernetes: Part 1, Recap 39 Kubernetes: Part 2, Interview In this part, we will talk about Kubernetes-related interview questions. On purpose, I will not use any kubectl commands, because I want you to build… 40 Kubernetes: Part 3, GitOps By this point, an interviewer can see that you know your way around Kubernetes. You can deploy components to a cluster. If something goes wrong, you can… 41 The Problem with Open Source Companies love open source solutions. Mostly because these solutions are free. But are they really as good?