System design resources, free first¶
Guides, official prep pages, books, channels, newsletters, engineering blogs and papers, each with one line on how to use it. Free comes first in every table; paid is marked. Prices and free tiers are as of Oct 2026.
If you only use five¶
- Hello Interview: System Design in a Hurry (freemium). Your main text and your problem set. Read the intro, delivery, core concepts and key technologies pages in week 1, then do one free breakdown a day.
- ByteByteGo System Design Interview (13 chapters free). Your second explanation of every classic problem. Read chapters on scale, estimation and the framework first.
- System Design Primer (free). Concepts index, latency tables, Anki decks and 8 solved designs. Read its topics section in order during week 1.
- Karan Pratap Singh: System Design (free). A readable free textbook. Use it for any concept Hello Interview keeps behind its paywall.
- Excalidraw plus System Design Lab (free). Draw every practice design in Excalidraw; run System Design Lab's failure simulations once a week.
Official company prep pages¶
Read your company's page first. On format, it overrides every third-party guide below.
| Company | Page | What it tells you |
|---|---|---|
| Meta | Full Loop prep page (download the Full Loop guide PDF) | Design is 45 minutes, Systems Design or Product Architectural Design, graded on problem navigation, solution design, technical excellence and technical communication. Practice on paper in about 30 minutes per question. Learn Excalidraw. No AI tools or outside help |
| Amazon | SDE II interview prep and software development topics | SDE II: OA with 20 minutes of systems design scenarios; "at least one question on software systems design" in the loop. The topics page lists object-oriented design, databases and distributed computing, and hosts an official system design prep video |
| Atlassian | Engineering interviews, with candidate PDFs for backend and fullstack | Coding in two parts (Data Structures, Code Design, including an AI-enabled Code Design round), then a 60-minute system design round whose questions ladder up or down |
| Flipkart | SDE prep doc | Machine coding block of 120 minutes; design is either system design ("Design Twitter") or OOD ("Design a Parking Lot") |
| SRE Workbook: Non-Abstract Large System Design | Not an interview guide, but Google's own method for turning a whiteboard design into resource estimates. Read before SRE or infra loops |
Free guides and courses¶
| Resource | What it is | How to use it |
|---|---|---|
| System Design Primer | The standard open-source primer by Donne Martin: topic index, study guide, 4-step approach, solved designs, OOD notebooks, Anki decks | Read "System design topics" in order in week 1. Do 3 solved problems (Pastebin, Twitter, web crawler) after trying them yourself |
| Hello Interview: System Design in a Hurry (freemium) | Delivery framework, core concepts, key technologies, patterns, problem breakdowns with per-level expectations | Week 1: intro, delivery, core concepts, key technologies. Then one free breakdown a day: 25 to 30 minutes on Excalidraw first, then read |
| Hello Interview: How to prepare | Problems ranked Easy, Medium, Hard | Use it as your practice order (free Easy, then free Medium, then free Hard) |
| Hello Interview: System Design Course (freemium) | The same pages in a fixed order, with a quiz after each lesson | If you want a set path, follow it and swap each locked lesson for the matching Karan Pratap Singh chapter |
| ByteByteGo System Design Interview (freemium) | Alex Xu's books as a web course; 13 chapters open without login | Read the free chapters listed on Problems. Skip the login-gated ones unless you buy |
| Karan Pratap Singh: System Design | Free book covering networking, databases, caching, queues, consistency, plus 5 designs (repo) | One chapter an evening for anything that confuses you |
| AlgoMaster: 30 system design concepts | A one-post map of core concepts; the full AlgoMaster course is freemium (text free, videos paid) | Read on day 1 as a map, then use Fundamentals |
| interviewing.io: System design interview guide | A long guide written for seniors. Part 2 concepts, part 3 a 3-step framework, part 4 four worked problems | Read the section on who drives at mid-level vs senior. Use part 4 as extra worked examples |
| Tech Interview Handbook: System design | Short overview and resource picks by Yangshun Tay | Read once to calibrate when design is asked |
| awesome-system-design-resources | Curated free links per concept, plus interview problems | Use when you want a second explanation of one concept |
| ByteByteGo system-design-101 | One-page visual explainers (last updated April 2025) | Skim diagrams for protocols, caching and databases before mocks |
| awesome-scalability | A large list of real-world scaling articles by topic | Read only for one topic at a time. Do not try to read it all |
| InterviewReady system-design-resources | Gaurav Sen's list of papers and engineering posts | Pick 2 to 3 posts from the companies you interview with |
| Google SRE books | Google's site reliability books, free online | Read "Monitoring Distributed Systems" before any infra or SRE loop |
| Patterns of Distributed Systems (Unmesh Joshi) | A free catalog of patterns: write-ahead log, leader and followers, majority quorum, heartbeat, gossip, Lamport clock | Infra track: one pattern a day. It bridges interview-level concepts and DDIA |
| MIT Missing Semester and devops-exercises | Shell, git and tooling; DevOps interview questions | For infra and startup roles, per Jugal's startup post |
Practice tools and mock interviews¶
| Tool | What it is | How to use it |
|---|---|---|
| Excalidraw | Free browser whiteboard; Meta uses it for design rounds and it is the most popular choice at Amazon | Do every practice design in it so the tool is familiar on the day |
| System Design Lab | Free interactive simulations across LLD, HLD and distributed systems, no login | Jugal's three rules: start with the fundamentals track, run the simulations, say your reasoning out loud (post) |
| Aced Practice | Free peer mocks with monthly credits, including system design; Pramp sessions moved here in July 2024 | Book 2 peer system design mocks in your final week |
| interviewing.io AI Interviewer | Free AI mock interviewer | Use for extra reps between peer mocks |
| Codemia (freemium) | System design practice problems with feedback | Optional written practice |
| interviewing.io (paid mocks) | Anonymous mocks with engineers from big tech, including system design | One paid mock before an E4 or SDE II loop, if budget allows |
| Hello Interview Premium (paid) | Premium breakdowns plus AI Guided Practice for system design, LLD and AI coding. Live human mocks ended May 31, 2026 (notice) | Only after you finish the free problems |
Books¶
| Book | Free or paid | How to use it |
|---|---|---|
| Distributed Systems lecture notes (Martin Kleppmann, Cambridge) | Free | Short and rigorous. Read the replication and consensus sections instead of buying DDIA |
| Google SRE books | Free online | Monitoring and reliability chapters for infra roles |
| Machine Learning Interviews Book (Chip Huyen) | Free | Skim the ML system design and process chapters for ML roles |
| Machine Learning Systems Design booklet (Chip Huyen) | Free (repo last updated 2023) | Read the case studies and exercises |
| System Design Interview, Vol 1 and Vol 2 (Alex Xu; Vol 2 with Sahn Lam) | Paid; 13 chapters free online | Read the free chapters. Buy only if you want Vol 2 topics |
| Understanding Distributed Systems (Roberto Vitillo) | Paid | A shorter, cheaper alternative to DDIA for 1 to 3 years of experience |
| Designing Data-Intensive Applications, 2nd edition (Kleppmann, Riccomini; O'Reilly, March 2026; 670 pages) | Paid (book site) | Not a 4-week interview book. Read only the replication, partitioning, transactions or consistency chapter when a topic confuses you. Read the rest after you land the job |
| Designing Machine Learning Systems (Chip Huyen, 2022) | Paid (companion repo) | ML roles: data, features, deployment and monitoring chapters |
| AI Engineering (Chip Huyen, 2025) | Paid (resources repo) | AI engineer loops: evaluation, RAG, agents and inference chapters |
| Machine Learning System Design Interview (Ali Aminian, Alex Xu) | Paid | Pair each chapter with Hello Interview's free ML breakdown on the same topic |
| Generative AI System Design Interview (ByteByteGo) | Paid | Only for GenAI or AI engineer roles |
YouTube¶
| Channel or video | What it is | How to use it |
|---|---|---|
| ByteByteGo | Short animated explainers from the System Design Interview authors | Watch one 5 to 10 minute concept video before reading the matching chapter |
| Hello Interview | Full mock-style walkthroughs of Hello Interview problems | After reading a breakdown, watch the matching video at 1.25x and pause before each section to predict the next step |
| Gaurav Sen | Classic concept explainers (consistent hashing, sharding) and newer AI topics. Jugal lists it in his Amazon roadmap | Concept intuition in weeks 1 and 2 |
| Jordan has no life | Fast, distributed-systems-heavy design videos | For Meta E4 infra track or SDE II and up. Too much for week 1 |
| Arpit Bhayani | Systems internals and real architecture breakdowns; paid courses at arpitbhayani.me | Database and internals videos when an interviewer may push on how things work |
| Concept && Coding (Shrayansh Jain) | LLD and HLD channel widely used by India candidates | LLD pattern and problem videos during machine coding prep, after you attempt each problem |
| Harvard CS75: Scalability (David Malan, 2012) | One lecture on vertical and horizontal scaling, caching, load balancing, replication, partitioning | Watch once in week 1 |
| MIT 6.824 lectures (2020) | Robert Morris's distributed systems lectures | Optional: MapReduce, GFS, Raft and Spanner lectures for infra roles |
| How I cleared Amazon Technical Interview, DSA + System Design, 4 week plan (Jugal Bhatt) | Jugal's own Amazon prep plan | Watch before the 4-week plan |
Newsletters and blogs¶
| Newsletter | What it is | How to use it |
|---|---|---|
| ByteByteGo Newsletter (freemium) | Weekly system design posts by Alex Xu's team; Jugal lists it in his Amazon roadmap | Subscribe and read the free weekly issue. Search the archive by topic |
| AlgoMaster Newsletter (freemium) | System design and LLD articles, including SOLID with code | Read the LLD posts during LLD week |
| Hello Interview blog | Interview process updates and guides | Check before your loop for format changes |
| Hello Interview: In the Wild | Interview-focused digests of real engineering posts: Discord, Figma, Meta, Shopify, Slack, Spotify | Read one a week to learn how real systems make trade-offs |
| Ascend (Jugal's Substack) | Weekly posts on job search, interviews and AI careers | See the post table below and the full Substack index |
Engineering blogs by company¶
Read 2 posts from your target company's blog before the loop. They give you real trade-offs to mention and good questions to ask your interviewer.
| Company | Blog | Read these first |
|---|---|---|
| Meta | Engineering at Meta | TAO and the life of a typeahead query |
| Netflix | Netflix TechBlog | Posts on streaming and data infrastructure |
| Uber | Uber Engineering | H3 geospatial index and dispatch posts |
| Stripe | Stripe engineering blog | Idempotency and rate limiters |
| LinkedIn Engineering | LinkedIn created Kafka; read its streaming and infrastructure posts | |
| Cloudflare | Cloudflare Blog | Networking, CDN and DDoS posts |
| Flipkart | Flipkart Tech Blog | Any 2 recent backend posts |
| Amazon | AWS Builders' Library, AWS Well-Architected | Timeouts, retries and backoff with jitter and the reliability pillar before SDE II |
| Discord | Discord engineering | How Discord stores trillions of messages before chat problems |
| Slack | Slack Engineering | Real-time messaging |
| Dropbox | Dropbox Tech | Storage and sync posts before Dropbox or Drive problems |
| Figma | Figma blog | How multiplayer editing works, before collaborative editing problems |
To find any other company's blog, search kilimchoi/engineering-blogs (last updated August 2024, so some links are stale) or the System Design Primer's company engineering blogs list.
Papers (optional, for infra roles)¶
New grads do not need these. Read them if your loop is infrastructure-heavy or you want depth behind a concept.
| Paper or course | What it teaches | How to use it |
|---|---|---|
| Dynamo (Amazon, 2007) | Consistent hashing, quorums and vector clocks in a key-value store | Read sections 4 and 5 after ByteByteGo's key-value store chapter |
| The Google File System | Distributed file system design | Optional; it is an MIT 6.5840 reading |
| Bigtable | Wide-column storage | Optional |
| MapReduce | Batch processing model | Pair with MIT Lab 1 |
| Spanner | A globally consistent database using synchronized clocks | Optional |
| Raft paper | Understandable consensus | Read with the visual walkthrough |
| Scaling Memcache at Facebook | Caching at very large scale: leases, thundering herd | Before distributed cache problems |
| TAO | Facebook's social graph store | Before Meta infra loops |
| MIT 6.5840 Distributed Systems | The course formerly called 6.824. Spring 2026 labs: MapReduce, key/value server, Raft, fault-tolerant key/value service, sharded key/value service | Infra candidates: do Lab 1 (MapReduce) |
| Papers We Love and awesome-distributed-systems | Paper indexes | Optional browsing |
Front-end and mobile system design¶
For front-end, fullstack and mobile roles (for example Meta Product Architecture or Atlassian fullstack).
| Resource | What it is | How to use it |
|---|---|---|
| GreatFrontEnd: Front End System Design Playbook (freemium) | A front-end design framework plus 20+ solved questions by Yangshun Tay. Most solved questions are premium as of Oct 2026 | Learn the framework pages, then attempt the free questions |
| mobile-system-design | A free framework for iOS and Android design rounds, with suggested timings | Use it in place of the backend framework for mobile loops |
ML and AI system design¶
Entry-level ML roles usually skip ML system design (Hello Interview). Use this list for mid-level ML loops and for LLM product design questions.
| Resource | What it is | How to use it |
|---|---|---|
| Hello Interview: ML System Design in a Hurry (early access, mostly free) | Interview types, delivery framework, core concepts | Read the intro and delivery pages, then the core concepts |
| Hello Interview ML breakdowns | Free: video recommendations, harmful content, bot detection | Do all three timed at 45 minutes before reading |
| AIMLInterviews | ML and AI interview guide with an ML system design template | Use its template and its list of common ML design questions |
| Stanford CS 329S | Course site for ML systems design with lecture notes | Optional depth |
| Eugene Yan: System design for recommendations and search | The offline and online, retrieval then ranking pattern | Read before any recommendation or feed ML design |
| Eugene Yan: Patterns for LLM systems | Evals, RAG, fine-tuning, caching, guardrails | Use as your LLM design checklist |
| Chip Huyen: Building a generative AI platform | An LLM app architecture built in five steps: context (RAG), guardrails, model router and gateway, cache, write actions; plus observability | Default skeleton for "design a RAG chatbot" or "design an LLM gateway" |
| Anthropic: Building effective agents | Workflows vs agents and common agent patterns | Learn the pattern names before any agent design question |
| Evidently AI: ML and LLM system design case studies | A database of 800 real case studies | Pick 3 from your target company and explain each in 2 minutes |
| eugeneyan/applied-ml | Papers and posts on ML in production, by company | Pick posts from your target company |
| Made With ML | Free MLOps and production ML lessons | Jugal's daily habit: one infra concept a day, two lines in your own words (post) |
Paid courses (only after the free stack)¶
| Course | Price (Oct 2026) | Notes |
|---|---|---|
| Hello Interview Premium | List: $59 for 1 month, $99 for 1 year, $349 lifetime. On sale Oct 4, 2026 for $47, $79 and $279. No plan auto-renews | Adds premium breakdowns, the 7 pattern pages, numbers-to-know and Guided Practice |
| ByteByteGo courses | Paid; free preview chapters; the FAQ says no refunds | System design, ML design, GenAI design, OOD and coding courses |
| Grokking System Design Interview (DesignGurus) | $148 on Oct 4, 2026 | DesignGurus calls it the original Grokking course. The free stack covers the same problems |
| Grokking System Design Interview: Patterns and Mock Interviews (Educative) | Subscription | A different course with the same brand. Jugal's Amazon roadmap calls it "Paid but worth it" |
| InterviewReady (Gaurav Sen) | Paid | System design and AI engineering courses |
| Aced (formerly Exponent) | Freemium | Read the free company guides (Google, Meta, Amazon, Uber, Microsoft) before paying for anything |
Jugal's posts that help with design rounds¶
| Post | Use it for |
|---|---|
| Amazon is still hiring after the biggest layoffs (his 6-week Amazon roadmap) | Scope of entry-level design (parking lot, not Netflix), the focus list, and twice-daily mocks in week 5 |
| The Definitive Guide for Meta and Amazon Engineering Interviews | Meta's design round is for E4 and up; E3 may get another coding round instead |
| How to Crack FAANG Interviews (Part 5) | Netflix: how much its loop weighs system design, even for IC roles |
| How to Crack FAANG Interviews (Part 4) | Apple: Jugal found his loop systems-heavy, with a focus on clarity of thought and edge cases |
| Want a Job in the Next 30 Days? Use these 5 websites | System Design Lab as week 3 of a 30-day plan |
| How I Got My First Startup Offer in 17 Days | Practical trade-offs startups test: S3 vs GCS, when to use SQS |
| How to Prepare for FAANG AI Engineer Internship Season | Defending design decisions from your own projects |
| How to become an AI engineer in 2026 | How to explain a project; include an architecture diagram with every project |
| AI Engineering 101 | The production habit: routing, caching and rate limiting for LLM apps |
| 7 videos on shipping ML to production | The README checklist, including "what breaks at scale" and "what you would monitor" |
| 7 videos to master RAG | RAG as a design building block; video 5 gives a whiteboard framing |
| Breaking into High-Frequency Trading (HFT) Firms | Low-latency design topics: multithreading, locks and mutexes; TCP vs UDP; kernel bypass (DPDK, RDMA) |
Skip these¶
- GitHub repos that copy paid "Grokking" course text. They appear to be unauthorized mirrors.
- The System Design Primer's "additional interview questions" table. Most of its links point to 2010 to 2014 sources. Use the primer for concepts and its own solved problems.
- Slow or stale repos as your main source: system-design-101 (last update April 2025), kilimchoi/engineering-blogs (August 2024), chiphuyen/machine-learning-systems-design (2023). Prefer the active ones above.
- Reading DDIA cover to cover inside a 4 to 6 week interview window.
- Any "AI copilot" that answers for you during a live interview. Standard rounds at Google ban AI tools; use AI only in rounds that say they allow it.
Next: Behavioral interviews