https://interviewready.io/learn/system-design-course/how-do-i-use-this-course/what-do-we-offer https://cdn.interviewready.io/lesson-videos/v1/802213760/poster.jpg What do we offer? Walkthrough of the System Design Simplified course structure, covering the machine coding, high level design and fundamentals sections, recorded live sessions, and platform features such as notes and quizzes. https://cdn.interviewready.io/lesson-videos/v1/802213760/720p.mp4 189 2022-07-13T00:43:26.442Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/1-what-is-system-design https://cdn.interviewready.io/lesson-videos/v1/1027797698/poster.jpg #1: What is System Design? Introduces system design through an e-commerce example: a T-shirt seller outgrows Shopify's payment and delivery integrations, leading to custom pages, a server and simple JSON APIs. https://cdn.interviewready.io/lesson-videos/v1/1027797698/720p.mp4 500 2024-11-08T20:33:04.129Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/2-hosting-the-application-servers https://cdn.interviewready.io/lesson-videos/v1/1027797823/poster.jpg #2: A star-tup is born! Compares self-hosting on a spare computer with renting cloud compute, then weighs managed servers against serverless for a small e-commerce startup and explains why serverless is chosen. https://cdn.interviewready.io/lesson-videos/v1/1027797823/720p.mp4 267 2024-11-09T13:36:35.200Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/3-webpages-and-cdn https://cdn.interviewready.io/lesson-videos/v1/1027806031/poster.jpg #3: Where are the pages? Explains serving static pages from a CDN such as CloudFront with S3 as the source, keeping dynamic data on the server, resolving a custom domain through DNS and Route 53, and choosing a startup database. https://cdn.interviewready.io/lesson-videos/v1/1027806031/720p.mp4 580 2024-11-09T13:35:05.340Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/4-debugging-in-the-trenches https://cdn.interviewready.io/lesson-videos/v1/1027839958/poster.jpg #4: Debugging in the trenches Shows how request-level logging with CloudWatch and dashboards such as Google Analytics speed up debugging, then identifies single points of failure in the store's architecture and how to handle them. https://cdn.interviewready.io/lesson-videos/v1/1027839958/720p.mp4 445 2024-11-15T13:11:42.585Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/4-1-hard-questions-harder-answers https://cdn.interviewready.io/lesson-videos/v1/1027840206/poster.jpg #4.1: Hard questions, harder answers Covers how a tech lead answers founder questions on microservices and language choice, estimates the cost of a virtual try-on feature and its storage, and why API contracts matter. https://cdn.interviewready.io/lesson-videos/v1/1027840206/720p.mp4 424 2024-11-15T13:16:37.076Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/5-serverless-or-server-more https://cdn.interviewready.io/lesson-videos/v1/1027840409/poster.jpg #5: Serverless or Server-More? Follows the store from serverless to a reserved AWS instance, through vertical scaling to a fleet of servers behind Elastic Load Balancing, covering round robin, least connections and geo-based DNS load balancing. https://cdn.interviewready.io/lesson-videos/v1/1027840409/720p.mp4 894 2024-11-22T16:51:53.871Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/6-database-like-memory-cache-like-recall https://cdn.interviewready.io/lesson-videos/v1/1034566624/poster.jpg #6: Database-like Memory, Cache-like Recall Explains caching for a slow products page, compares in-memory and global caches, then covers sharding with hash-mod routing and consistent hashing with virtual points to cut cache warm-up time. https://cdn.interviewready.io/lesson-videos/v1/1034566624/720p.mp4 1197 2024-11-29T16:01:19.816Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/7-the-case-of-the-expensive-cache https://cdn.interviewready.io/lesson-videos/v1/1035494994/poster.jpg #7: The case of the Expensive Cache Diagnoses an expensive Redis setup that queried the database on every read and stored heavy objects, then explains cache expiry, write-through, write-behind, look-aside caching and LRU and LFU eviction. https://cdn.interviewready.io/lesson-videos/v1/1035494994/720p.mp4 822 2024-12-03T10:29:45.798Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/8-sale-day-jitters https://cdn.interviewready.io/lesson-videos/v1/1035495486/poster.jpg #8: Sale Day Jitters Follows a flash sale that fails under bot traffic, then covers load testing, web application firewalls, request priority, short-circuiting, back pressure, head-of-line blocking and token and leaky bucket rate limiting. https://cdn.interviewready.io/lesson-videos/v1/1035495486/720p.mp4 1451 2024-12-03T10:46:24.556Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/9-a-new-cto-is-born https://cdn.interviewready.io/lesson-videos/v1/1039211075/poster.jpg #9: A new CTO is born! As the startup's new CTO grows the team from 5 to 15 engineers, the lesson covers splitting a monolith into team-owned services, avoiding nano services, and managing API contracts with versioned client libraries. https://cdn.interviewready.io/lesson-videos/v1/1039211075/720p.mp4 998 2024-12-14T13:44:12.430Z yes https://interviewready.io/learn/system-design-course/building-an-ecommerce-app-1-to-1m/10-concluding-the-series https://cdn.interviewready.io/lesson-videos/v1/1040356186/poster.jpg #10: Concluding the series! The final part of the e-commerce series turns business complaints about slow data queries into a data warehouse design, comparing Kinesis and Athena with Kafka, HDFS or S3, and Spark. https://cdn.interviewready.io/lesson-videos/v1/1040356186/720p.mp4 585 2024-12-27T20:52:55.395Z yes https://interviewready.io/learn/system-design-course/databases-deep-dive/what-are-databases https://cdn.interviewready.io/lesson-videos/v1/889363495/poster.jpg What are Databases? An introduction to databases as structured, durable data stores, comparing them with application servers, file systems and in-memory databases. https://cdn.interviewready.io/lesson-videos/v1/889363495/720p.mp4 279 2023-11-29T20:54:21.121Z yes https://interviewready.io/learn/system-design-course/databases-deep-dive/storage-and-retrieval https://cdn.interviewready.io/lesson-videos/v1/889363273/poster.jpg Storage and Retrieval An overview of how databases store data using indexes such as B+ trees and hash tables, how typed tables sit on top of them, and how SQL queries are processed and optimized. https://cdn.interviewready.io/lesson-videos/v1/889363273/720p.mp4 264 2023-11-29T21:12:05.889Z yes https://interviewready.io/learn/system-design-course/consistency-in-distributed-systems/what-is-data-consistency https://cdn.interviewready.io/lesson-videos/v1/808266525/poster.jpg What is Data Consistency? Defines data consistency in distributed systems as a measure of how up to date a piece of data is, and explains why highly consistent systems are easier to reason about. https://cdn.interviewready.io/lesson-videos/v1/808266525/720p.mp4 90 2023-03-15T11:14:38.384Z yes https://interviewready.io/learn/system-design-course/system-design-tradeoffs/introduction-to-design-tradeoffs https://cdn.interviewready.io/lesson-videos/v1/835393237/poster.jpg Introduction to design tradeoffs Introduces design trade-offs through the non-functional requirements of uploading and viewing pictures on Instagram, showing how durability, quality and response time compete with cost. https://cdn.interviewready.io/lesson-videos/v1/835393237/720p.mp4 238 2023-06-15T10:16:05.720Z yes https://interviewready.io/learn/system-design-course/tao-graph-database-at-meta/1-usecases-and-data-schema https://cdn.interviewready.io/lesson-videos/v1/933674994/poster.jpg 1. Usecases and Data Schema A live walkthrough of Meta's TAO paper covering why a graph layer was built over memcache and MySQL, the objects and associations data model, its query APIs, sharding and inverse edge writes. https://cdn.interviewready.io/lesson-videos/v1/933674994/720p.mp4 4601 2024-04-12T11:43:55.155Z yes https://interviewready.io/learn/system-design-course/tao-graph-database-at-meta/tao-data-consistency-and-evictions https://cdn.interviewready.io/lesson-videos/v1/939089434/poster.jpg 2. Data Consistency and evictions A live walkthrough of Meta's TAO paper covering cross-region replication with change data capture, the leader and follower model for writes, cache consistency and refill messages. https://cdn.interviewready.io/lesson-videos/v1/939089434/720p.mp4 4987 2024-04-25T12:43:31.000Z yes https://interviewready.io/learn/system-design-course/basics/horizontal_vs_vertical_scaling https://cdn.interviewready.io/lesson-videos/v1/674066094/poster.jpg Horizontal vs Vertical Scaling Starts from exposing code through an API and hosting it in the cloud, then compares vertical scaling (bigger machines) with horizontal scaling (more machines) across five trade-offs. https://cdn.interviewready.io/lesson-videos/v1/674066094/720p.mp4 472 2022-02-06T10:38:53.053Z yes https://interviewready.io/learn/system-design-course/basics/monoliths_vs_microservices https://cdn.interviewready.io/lesson-videos/v1/674065945/poster.jpg Monoliths vs Microservices Corrects common misconceptions about monoliths and microservices and compares the advantages and disadvantages of each architecture, including how to justify the choice in a system design interview. https://cdn.interviewready.io/lesson-videos/v1/674065945/720p.mp4 462 2022-02-06T10:37:23.769Z yes https://interviewready.io/learn/system-design-course/basics/sharding https://cdn.interviewready.io/lesson-videos/v1/669291525/poster.jpg Sharding An explanation of database sharding as horizontal partitioning by a key, covering shard key choice, expensive cross-shard joins, hierarchical sharding, indexes within shards and master-slave replication for failures. https://cdn.interviewready.io/lesson-videos/v1/669291525/720p.mp4 535 2022-06-24T08:42:07.202Z yes https://interviewready.io/learn/system-design-course/basics/single_point_of_failure https://cdn.interviewready.io/lesson-videos/v1/672326681/poster.jpg Single Point of Failure An explanation of single points of failure in system design and how to remove them layer by layer using redundant nodes, database replication, multiple load balancers behind DNS, and multi-region deployment. https://cdn.interviewready.io/lesson-videos/v1/672326681/720p.mp4 360 2022-02-06T09:37:26.853Z yes https://interviewready.io/learn/system-design-course/basics/capacity-planning-and-estimation-how-much-data-does-youtube-store-daily https://cdn.interviewready.io/lesson-videos/v1/791781471/poster.jpg Capacity Planning and Estimation: How much data does YouTube store daily? A worked capacity estimation example for YouTube: daily video storage with replication and multiple resolutions, cache sizing for thumbnails, and the number of processors needed for video processing. https://cdn.interviewready.io/lesson-videos/v1/791781471/720p.mp4 791 2023-01-23T06:49:30.361Z yes https://interviewready.io/learn/system-design-course/api_design/api_design_goals https://cdn.interviewready.io/lesson-videos/v1/674093792/poster.jpg API Design Goals Defines an API as a contract for external callers and works through naming, parameters, responses and error design with the example of fetching the admins of a WhatsApp group. https://cdn.interviewready.io/lesson-videos/v1/674093792/720p.mp4 381 2022-02-06T10:49:03.597Z yes https://interviewready.io/learn/system-design-course/api_design/api_design_in_practice https://cdn.interviewready.io/lesson-videos/v1/674094175/poster.jpg API Design in Practice Applies API design to HTTP endpoints using group admin and member APIs, covering routing, side effects and atomicity, pagination, fragmentation, consistency, caching and service degradation. https://cdn.interviewready.io/lesson-videos/v1/674094175/720p.mp4 536 2022-02-06T10:52:03.126Z yes https://interviewready.io/learn/system-design-course/consistency_vs_availability/distributed_data_consistency https://cdn.interviewready.io/lesson-videos/v1/674062717/poster.jpg Distributed data consistency An introduction to data consistency in distributed systems, using an early Facebook-style setup to show the single point of failure, vertical scaling limits and latency problems of a single server. https://cdn.interviewready.io/lesson-videos/v1/674062717/720p.mp4 358 2022-02-06T10:05:07.427Z yes https://interviewready.io/learn/system-design-course/consistency_vs_availability/data_consistency_across_continents https://cdn.interviewready.io/lesson-videos/v1/674062281/poster.jpg Data Consistency across Continents Using a Facebook-style example with Harvard and Oxford servers, this lesson compares caching remote data with replicating it across continents and introduces the problem of propagating updates consistently. https://cdn.interviewready.io/lesson-videos/v1/674062281/720p.mp4 314 2022-02-06T10:04:19.404Z yes https://interviewready.io/learn/system-design-course/consistency_vs_availability/leader-follower_architectures https://cdn.interviewready.io/lesson-videos/v1/674062152/poster.jpg Leader-follower architectures This lesson covers acknowledgements and retries when replicating updates across regions, the two generals problem, and how a leader-follower architecture forces a choice between consistency and availability. https://cdn.interviewready.io/lesson-videos/v1/674062152/720p.mp4 297 2022-02-06T10:01:14.014Z yes https://interviewready.io/learn/system-design-course/consistency_vs_availability/tradeoffs_-_2_phase_commit_protocol https://cdn.interviewready.io/lesson-videos/v1/674061938/poster.jpg Tradeoffs - 2 phase commit protocol A walkthrough of the two-phase commit protocol between a leader and its followers, covering prepare, commit, rollback, retries with transaction IDs, and the availability cost of strict consistency. https://cdn.interviewready.io/lesson-videos/v1/674061938/720p.mp4 571 2022-02-06T09:59:39.771Z yes https://interviewready.io/learn/system-design-course/messaging_and_event_handling/the-message-queue https://cdn.interviewready.io/lesson-videos/v1/672327775/poster.jpg The Message Queue: Problem Statement This lesson uses a pizza shop to introduce asynchronous processing with an order queue, and shows why an in-memory list fails when one outlet in a chain goes down. https://cdn.interviewready.io/lesson-videos/v1/672327775/720p.mp4 249 2022-02-06T09:41:11.215Z yes https://interviewready.io/learn/system-design-course/messaging_and_event_handling/asynchronous_processing_benefits https://cdn.interviewready.io/lesson-videos/v1/672327310/poster.jpg Asynchronous processing: benefits Using a pizza shop with several servers, this lesson shows how heartbeats, consistent hashing and persistence handle crashed servers, and how a message or task queue such as RabbitMQ bundles these features. https://cdn.interviewready.io/lesson-videos/v1/672327310/720p.mp4 334 2022-02-06T09:39:55.738Z yes https://interviewready.io/learn/system-design-course/messaging_and_event_handling/publisher_subscriber_models https://cdn.interviewready.io/lesson-videos/v1/672325416/poster.jpg Publisher Subscriber Models A comparison of request-response and publish-subscribe communication between microservices using a message broker such as Kafka or RabbitMQ, with a fund transfer example showing where pub-sub breaks consistency. https://cdn.interviewready.io/lesson-videos/v1/672325416/720p.mp4 680 2022-02-06T09:35:01.848Z yes https://interviewready.io/learn/system-design-course/no_sql_databases/difference_between_sql_and_no_sql https://cdn.interviewready.io/lesson-videos/v1/674064597/poster.jpg Difference between SQL and NoSQL Compares how a user record with an address is stored in a relational database and in a NoSQL document, then lists the main advantages and disadvantages of NoSQL and when to choose it. https://cdn.interviewready.io/lesson-videos/v1/674064597/720p.mp4 587 2022-02-06T10:21:30.338Z yes https://interviewready.io/learn/system-design-course/no_sql_databases/cassandra_internals https://cdn.interviewready.io/lesson-videos/v1/674064404/poster.jpg Cassandra Internals A walkthrough of a five-node Cassandra cluster: hashing request keys to nodes, handling a poor hash function with multi-level sharding, replicating data to neighbouring nodes, and the need for consensus. https://cdn.interviewready.io/lesson-videos/v1/674064404/720p.mp4 455 2022-02-06T10:23:34.926Z yes https://interviewready.io/learn/system-design-course/interview_tips/system_design_tips https://cdn.interviewready.io/lesson-videos/v1/674065775/poster.jpg System Design Tips Five dos and don'ts for system design interviews, plus the three qualities interviews tend to assess: clarity of thought, flexibility and knowledge of existing solutions. https://cdn.interviewready.io/lesson-videos/v1/674065775/720p.mp4 457 2022-02-06T10:35:42.008Z yes https://interviewready.io/learn/system-design-course/interview_tips/dos_and_don'ts https://cdn.interviewready.io/lesson-videos/v1/674065589/poster.jpg Dos and Don'ts Covers five system design interview mistakes: a premeditated introduction, unneeded capacity estimation, ignoring network protocols, not knowing system internals, and skipping trade-offs, plus a bonus tip to stay on the core problem. https://cdn.interviewready.io/lesson-videos/v1/674065589/720p.mp4 394 2022-02-06T10:33:44.693Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/the_need_for_good_coding_practices https://cdn.interviewready.io/lesson-videos/v1/1037440844/poster.jpg What is Low Level Design? Defines low level design as a mix of design and coding and introduces readability, extensibility and correctness as the three measures of good code. https://cdn.interviewready.io/lesson-videos/v1/1037440844/720p.mp4 204 2023-12-15T23:23:45.304Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/introduction-to-low-level-design-series https://cdn.interviewready.io/lesson-videos/v1/895434873/poster.jpg Introduction to Low Level Design Series Introduces the low level design series, which covers guiding principles such as SOLID, inheritance and composition, and design patterns, through building a turn-based game AI engine. https://cdn.interviewready.io/lesson-videos/v1/895434873/720p.mp4 131 2023-12-17T03:38:43.639Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/setting_requirements_and_objects https://cdn.interviewready.io/lesson-videos/v1/891330733/poster.jpg Setting Requirements and Objects A turn-based game AI engine is written without any upfront design, defining start, move and isComplete APIs and a tic-tac-toe board whose win-checking logic grows into nested loops and conditions. https://cdn.interviewready.io/lesson-videos/v1/891330733/720p.mp4 784 2023-12-15T19:35:44.430Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/api_and_package_structuring https://cdn.interviewready.io/lesson-videos/v1/891331038/poster.jpg API and Package Structuring The tic-tac-toe game engine is refactored by moving classes into separate files and packages, turning the main class into a GameEngine API, and replacing direct array access with a getter. https://cdn.interviewready.io/lesson-videos/v1/891331038/720p.mp4 590 2023-12-15T19:36:10.321Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/parent_vs._base_class_functions https://cdn.interviewready.io/lesson-videos/v1/891331242/poster.jpg Parent vs. Base class functions The game engine refactor continues by placing getCell and setCell in TicTacToeBoard rather than the base Board class, adding a Cell class, and implementing start and move for tic-tac-toe. https://cdn.interviewready.io/lesson-videos/v1/891331242/720p.mp4 248 2023-12-15T19:36:25.146Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/setting_the_main_method https://cdn.interviewready.io/lesson-videos/v1/891331354/poster.jpg Setting the main method A Main class is written to play tic-tac-toe through the game engine, looping between user moves and a naive computer move that picks the first empty cell until the game is complete. https://cdn.interviewready.io/lesson-videos/v1/891331354/720p.mp4 202 2023-12-15T19:36:38.130Z yes https://interviewready.io/learn/low-level-design-course/building-a-game-engine/debugging_the_code https://cdn.interviewready.io/lesson-videos/v1/891331439/poster.jpg Debugging the code The tic-tac-toe engine is run and debugged, fixing null pointer exceptions, an incorrect diagonal check and a missing column break, then tested on rows, columns and both diagonals. https://cdn.interviewready.io/lesson-videos/v1/891331439/720p.mp4 573 2023-12-15T19:36:54.946Z yes https://interviewready.io/learn/low-level-design-course/low-level-design-payment-tracking-app-like-splitwise/problem_statement https://cdn.interviewready.io/lesson-videos/v1/559873634/poster.jpg Problem Statement Problem statement for the Splitwise low level design: adding, editing and settling expenses, group expenses with simplified debts, comments and an activity log, and which features to implement. https://cdn.interviewready.io/lesson-videos/v1/559873634/720p.mp4 219 2021-06-08T11:45:30.047Z yes https://interviewready.io/learn/low-level-design-course/machine-coding-a-cache/1_caching_engineering_requirements https://cdn.interviewready.io/lesson-videos/v1/558968127/poster.jpg #1: Caching: Engineering requirements The first lesson on machine coding a cache sets its requirements: reads, updates and evictions, the trade-off between write-back and write-through policies, and a read-your-own-writes guarantee. https://cdn.interviewready.io/lesson-videos/v1/558968127/720p.mp4 324 2021-06-07T12:07:32.884Z yes https://interviewready.io/learn/low-level-design-course/machine-coding-a-rate-limiter/what-will-you-learn https://cdn.interviewready.io/lesson-videos/v1/808690712/poster.jpg What will you learn Introduces the machine coding chapter on rate limiters: what a rate limiter is, its scope, options for handling rejected requests, and the back pressure, token bucket and timer wheel approaches. https://cdn.interviewready.io/lesson-videos/v1/808690712/720p.mp4 368 2023-03-18T11:55:31.857Z yes https://interviewready.io/learn/ai-engineering/who-is-this-course-for/course-intro https://cdn.interviewready.io/lesson-videos/v1/1087367958/poster.jpg Course Intro Course introduction covering the two main topics, large language models and vector databases, the intended audience of engineers and product leads, prerequisites, assignments and completion certificate. https://cdn.interviewready.io/lesson-videos/v1/1087367958/720p.mp4 120 2025-06-03T09:15:41.984Z yes https://interviewready.io/learn/ai-engineering/who-is-this-course-for/usecase https://cdn.interviewready.io/lesson-videos/v1/1085100515/poster.jpg Usecase Introduces the course's running use case: an e-commerce t-shirt store whose order and delivery queries are expensive to handle manually, leading to an AI chat assistant that escalates to humans. https://cdn.interviewready.io/lesson-videos/v1/1085100515/720p.mp4 107 2025-06-03T09:18:32.491Z yes https://interviewready.io/learn/ai-engineering/year-2025/retrieval-augmented-generation-july-2025 https://cdn.interviewready.io/lesson-videos/v1/1100946632/poster.jpg July 2025 - Retrieval Augmented Generation Recorded July 2025 live class on retrieval augmented generation: embeddings, vector search with HNSW, vector database options, RAG versus fine-tuning, and prompt structure, with participants sharing production experience. https://cdn.interviewready.io/lesson-videos/v1/1100946632/720p.mp4 3808 2025-07-17T00:46:37.617Z yes https://interviewready.io/learn/behavioural-interview-course/Behavioural-Intro/course-intro-behavioral https://cdn.interviewready.io/lesson-videos/v1/738139733/poster.jpg Course Intro Course introduction explaining why behavioural interviews feel subjective, which competencies such as teamwork, goal commitment and resilience they measure, and how competency-based interviewing works. https://cdn.interviewready.io/lesson-videos/v1/738139733/720p.mp4 115 2022-08-10T09:11:58.561Z yes https://interviewready.io/learn/behavioural-interview-course/STAR-pattern/Why-is-STAR-used https://cdn.interviewready.io/lesson-videos/v1/768504640/poster.jpg Why is STAR used? Explains why structured interviews such as the STAR technique are preferred over traditional interviews, and why competencies rather than IQ explain differences in job performance. https://cdn.interviewready.io/lesson-videos/v1/768504640/720p.mp4 164 2022-11-08T14:34:43.380Z yes https://interviewready.io/learn/behavioural-interview-course/STAR-pattern/What-is-the-STAR-pattern https://cdn.interviewready.io/lesson-videos/v1/768502693/poster.jpg What is the STAR pattern Explains the STAR technique for behavioural interviews, covering what an interviewer wants to learn from the situation, task, action and result in a candidate's story. https://cdn.interviewready.io/lesson-videos/v1/768502693/720p.mp4 244 2022-11-08T14:35:51.182Z yes