# Tweets From Alex Xu  ## Metadata - Author: [[@alexxubyte on Twitter]] - Full Title: Tweets From Alex Xu - Category: #tweets - URL: https://twitter.com/alexxubyte ## Highlights - /1 How do Visa 𝐝𝐢𝐬𝐩𝐮𝐭𝐞 and 𝐜𝐡𝐚𝐫𝐠𝐞𝐛𝐚𝐜𝐤 work? A dispute happens when a cardholder disagrees with a merchant’s charge. A chargeback is a process of reversing the charge. Sometimes, the two terms are used interchangeably. https://t.co/Zh9erFoO9J  ([View Tweet](https://twitter.com/alexxubyte/status/1616109271758016513)) - Top architectural styles In software development, architecture plays a crucial role in shaping the structure and behavior of software systems. It provides a blueprint for system design, detailing how components interact with each other to deliver specific functionality. They… https://t.co/0c4I9qHRkx https://t.co/7jWtYILIZN  ([View Tweet](https://twitter.com/alexxubyte/status/1678423147496996865)) - Tags: [[favorite]] - How do companies ship code to production? The method to download the high-resolution PDF is available at the end. The diagram below illustrates the typical workflow. Step 1: The process starts with a product owner creating user stories based on requirements. Step 2: The dev team picks up the user stories from the backlog and puts them into a sprint for a two-week dev cycle. Step 3: The developers commit source code into the code repository Git. Step 4: A build is triggered in Jenkins. The source code must pass unit tests, code coverage threshold, and gates in SonarQube. Step 5: Once the build is successful, the build is stored in artifactory. Then the build is deployed into the dev environment. Step 6: There might be multiple dev teams working on different features. The features need to be tested independently, so they are deployed to QA1 and QA2. Step 7: The QA team picks up the new QA environments and performs QA testing, regression testing, and performance testing. Steps 8: Once the QA builds pass the QA team’s verification, they are deployed to the UAT environment, where the QA team, dev team, and even the product owner perform UAT testing. Step 9: If the UAT testing is successful, the builds become release candidates and will be deployed to the production environment on schedule. Here we might not want to deploy to all the users in one go to mitigate the change risks, so some techniques like feature toggle, canary deployment can be used. Step 10: SRE (Site Reliability Engineering) team is responsible for prod monitoring. They leverage a bunch of log-analyzing tools and process-tracing tools like ELK stack, Prometheus, and Skywalking. They report production issues to QA and dev teams, and teams need to fix them based on defined priority. – Subscribe to our newsletter to download the 𝐡𝐢𝐠𝐡-𝐫𝐞𝐬𝐨𝐥𝐮𝐭𝐢𝐨𝐧 𝐏𝐃𝐅. After signing up, find the download link on the success page: https://t.co/0v29X0VLNt ([View Tweet](https://twitter.com/alexxubyte/status/1711767230642635130)) - Netflix's Tech Stack. This post is based on research from many Netflix engineering blogs and open-source projects. If you come across any inaccuracies, please feel free to inform us. Mobile and web: Netflix has adopted Swift and Kotlin to build native mobile apps. For its web application, it uses React. Frontend/server communication: GraphQL. Backend services: Netflix relies on ZUUL, Eureka, the Spring Boot framework, and other technologies. Databases: Netflix utilizes EV cache, Cassandra, CockroachDB, and other databases. Messaging/streaming: Netflix employs Apache Kafka and Fink for messaging and streaming purposes. Video storage: Netflix uses S3 and Open Connect for video storage. Data processing: Netflix utilizes Flink and Spark for data processing, which is then visualized using Tableau. Redshift is used for processing structured data warehouse information. CI/CD: Netflix employs various tools such as JIRA, Confluence, PagerDuty, Jenkins, Gradle, Chaos Monkey, Spinnaker, Altas, and more for CI/CD processes. –- Subscribe to our weekly newsletter to get a Free System Design PDF (158 pages): https://t.co/uc5M7CdXXC<img src='https://pbs.twimg.com/media/GBAE4FObIAAJYKS.jpg'/> ([View Tweet](https://twitter.com/alexxubyte/status/1733891233859473857))  ## New highlights added September 5, 2024 at 2:01 AM > The Ultimate Software Architect Knowledge Map >  ([View Tweet](https://twitter.com/alexxubyte/status/1831357838981234756))  ## New highlights added November 8, 2024 at 3:00 AM > How To Release A Mobile App >  ([View Tweet](https://twitter.com/alexxubyte/status/1853840972565889494))  ## New highlights added February 4, 2025 at 12:44 AM > How does Git work? https://t.co/Nz4zmiYQnP >  ([View Tweet](https://twitter.com/alexxubyte/status/1886095722795483287))