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sergeyleschev/README.md

Sergey Leschev | Team Lead | CTO

Swift (L6+) | TypeScript (L6+) | Design Patterns (L6+) | System Architect (L7+)

Google Engineering Level: L7+


🏆 Awards

Ranking #Dev: Global TOP 200 (Certificate)

Sergey Leschev

Sergey Leschev

Languages: Swift, TypeScript, Shell, Database (T-SQL, PL/SQL, MySQL).

Algorithms: linked lists, binary search, hash table, queue/stack, dfs/bfs, sort, heap/hash, two pointers, sliding window, tree, greedy problems etc.

🚀 Developer Roadmap

  • S.Leschev iOS Developer (Google Engineering Level: L6+) Roadmap.
  • S.Leschev FullStack Developer (Google Engineering Level: L6+) Roadmap.
  • S.Leschev React Custom Hooks (Google Engineering Level: L6+) Roadmap.
  • S.Leschev Responsive Email Design (Google Engineering Level: L6+) Roadmap.
  • S.Leschev Design Patterns (Google Engineering Level: L6+) Roadmap.
  • S.Leschev System Architect (Google Engineering Level: L7+) Roadmap.

💻 Technologies

Tech Stack (L7+)

Swift [4, 5+, UIKit, MVP/VIPER/MVVM, Autolayout, UIKitPlus, GCD/Operations/Concurrency 5.5+, Alamofire, ObjectMapper, SwiftLint, SwiftGen, FP, pre/after-main opt], SwiftUI [iOS, watchOS, Widgets, App Clips], Apple TV/AirPlay [Composition, Secondary Display], Realm, Lottie, JWT, CryptoSwift, RxSwift, Vapor [4+] [API;Fluent;Migrations], SwiftNIO [2+], REST, Firebase, Java [7-8], PWA, Angular [2-6+], Ionic Framework [3-5+], React Native [Redux, MobX], JavaScript, React [Next.JS; Redux, Redux Tookit +Slice/Immer, Prime React], CSS [scss], Node.js [10x Express/SQL;14x NestJS 6;7;8+/TypeORM], TypeScript (+ESLint, Jest), C#, .Net Core [1-3+], MS SQL [2016+], SQL, Objective-C, MongoDB [3.6, 4.4, Config, Replication, Sharding], Elasticsearch, RabbitMQ, GraphQL [Schemas; Resolver; Request; Validation; Queries&Mutations; Apollo; Reactive], Apache Kafka, Mockapi, PostgreSQL, Redis, Memcached, Mac Os, iOS [10;12;13;14+], Android (Kotlin), OneSignal, Localization (Phrase/json/i18next), Zeplin, Figma, Sketch.

Analytics (L6+)

Tableau, Amplitude [SDK], AppsFlyer [SDK 5, 6+, Raw Data, Data Locker, Protect360, web-2-app, People-Based Attribution (PBA), Conversion Path, OneLink], Facebook for Business [SDK, Graph, Conversions Api, Pixel, Reports], Snapchat, TikTok, Google Tag Manager (GTM), Google Analytics [GA4;UA], Apple SKAd (+PCM), Qlik, Yandex, Hotjar, SplitMetrics, Apphud, Appfollow, A/B testing, Airflow, Airbyte, Qonversion.

Infra/DevOps (L6+)

Fastlane, CI/CD tools [XCode Cloud, Github Actions/DO, Jenkins, Codemagic, Gitlab, AWS CodeBuild], Git [+Flow], Chromium + Transporter, Instana, Freshworks, Docker [+compose], Kubernetes, Twilio, Zapier, Linux [+ssh, iptables, Ubuntu 16/18/20+, snap/apt/npm/yarn/brew], Amazon Web Services (AWS), Digital Ocean (DO), GRE, IPSEC, VPN, Cloudflare [DNS, CDN, SSL, Guard, Rules], Crashlytics, Grafana, Sentry, RayGun, Nginx, Let's Encrypt [SSL], Win Server [+PowerShell], IIS, Pingdom, UptimeRobot, Apache JMeter, PAW, Postman, Charles Proxy, Indigo Browser, Published Apps [Apple AppStore, Google Play, Amazon Appstore, Huawei AppGallery, Galaxy Store, Snapcraft].

Payment Providers (L6+)

Apple StoreKit [+Retention, Sales Reports], Stripe [nest-SDK, node-SDK, Stripe Checkout, Stripe Elements, Stripe Prebuilt Page, Stripe via iframe, Sigma SQL Financial Reports], PayPal [SDK], high-risk processing providers [Solid Payments, Recurly, SolidGate, Braintree], CloudPayments, DCB (fortumo), Paymentwall, SafeChange, CCBill, Klarna, Pikassa, Paymentwall, Exactly, Realisto, Cypix, Payselection.

DeFi

Web 3.0: Solidity, Javascript, Hardhat, REMIX, Ethers.js, Ganache, TypeScript (react.js, node.js). Solidity (Consensys, Alchemy), Metamask, SafePal, Launchpad, PancakeSwap (BNB), Uniswap (ETH), Dextools/PooCoin, Gas/gwei Optimization, Front-Runner Bots, Slippage Optimization, CEX/DEX, Binance Smart Chain (BNB), Ethereum (ETH), Polygon (Matic), Tokens List [Coinmarketcap;CoinGecko].

Auth Providers (L6+)

Apple ID, Google, Facebook (Meta), Fitbit.

Support Services (L6+)

Intercom, Hiver, ChargeBee, HelpShift, HelpCrunch, Freshchat.

Reports (L6+)

P&L, CF, Key metrics, Unit-economics [AARRR, RARRA], Cohort analysis.

PM Stack (L7+)

Agile [Scrum, Kanban, +V&E +ICE +RICE, PRINCE2], Driven Development [TDD, BDD/QUICK, DDD, FDD], ISTBQ, Clickup, Jira, Confluence, Notion, Asana, Team Foundation (TFS), Miro, diagrams.net/ERD, Microsoft Project, OmniPlan, UML [IBM Rational Rose, Visio], Reetro.

useArray useAsync useClickOutside useCookie useCopyToClipboard useDarkMode useDebounce useDebugInformation useDeepCompareEffect useEffectOnce useEventListener useFetch useGeolocation useHover useLongPress useMediaQuery useOnlineStatus useOnScreen usePrevious useRenderCount useScript useStateWithHistory useStateWithValidation useStorage useTimeout useToggle useTranslation useUpdateEffect useWindowSize

Behavioral Creational Structural
🐝 Chain Of Responsibility 🌰 Abstract Factory 🔌 Adapter
👫 Command 👷 Builder 🌉 Bridge
🎶 Interpreter 🏭 Factory Method 🌿 Composite
🍫 Iterator 🔂 Monostate 🍧 Decorator
💐 Mediator 🃏 Prototype 🎁 Facade
💾 Memento 💍 Singleton 🍃 Flyweight
👓 Observer ☔ Protection Proxy
🐉 State 🍬 Virtual Proxy
💡 Strategy
🏃 Visitor
📝 Template Method

Project Guidelines (L6+)

A set of best practices in my projects.


🏫 Education

Belarusian State University

2004 – 2009

Faculty of Applied Mathematics & Informatics.

Computer science / Mathematician-system programmer.


🏆 Awards

Golden Award for the Year of the Tiger Challenge

Sergey Leschev

Algorithmic skills: Dynamic programming, Greedy algorithms, Catepillar method, Binary search algorithm, Fibonacci numbers, Euclidean algorithm, Sieve of Eratosthenes, Prime and composite numbers, Maximum slice problem, Stack and Queues, Sorting, Time Complexity, Arrays, Prefix Sums, Leader, etc.

Contest: Algorithms, SQL, Data Structures, Bitwise operations (bit-ops), Frontend.


Licenses & certifications


🏆 Awards

Golden Award Muad'Dib's Challenge

Sergey Leschev

Algorithmic skills: Dynamic programming, Greedy algorithms, Binary search, Stack and Queues, Sorting, Time Complexity.

Contest: Algorithms, Data Structures.

Languages: Swift.


Favorite Book

My Favorite Book is Dale Carnegie "How to Win Friends & Influence People".

The principles of which I use in my life:

  1. Become genuinely interested in other people.
  2. Smile.
  3. Remember that a person's name is to that person the sweetest and most important sound in any language.
  4. Be a good listener.
  5. Talk in terms of the other person's interests.
  6. Make the other person feel important - and do it sincerely.

Contacts

I have a clear focus on time-to-market and don't prioritize technical debt. And I took part in the Pre-Sale/RFX activity as a System Architect, assessment efforts for Mobile (iOS-Swift, Android-Kotlin), Frontend (React-TypeScript) and Backend (NodeJS-.NET-PHP-Kafka-SQL-NoSQL). Moderator of DEV Community. And I also formed the work of Pre-Sale as a CTO from Opportunity to Proposal via knowledge transfer to Successful Delivery.

iOS Dev Skills. Performance Review. As a CTO, effective leadership goes beyond technical architecture. Conducting regular performance reviews is a crucial part of managing teams. I've compiled my insights on structuring the iOS development department, conducting performance reviews, and most importantly, emphasizing the significant distinctions between developers' levels based on well-defined criteria here.

🛩️ #startups #management #cto #swift #typescript #database

📧 Email: [email protected]

👋 LinkedIn: https://linkedin.com/in/sergeyleschev

👋 Twitter: https://twitter.com/sergeyleschev

👋 Github: https://github.com/sergeyleschev

🌎 Website: https://sergeyleschev.github.io

🌎 DEV Community (moderator): https://dev.to/sergeyleschev

🌎 Reddit: https://reddit.com/user/sergeyleschev

🌎 Quora: https://quora.com/sergey-leschev

🌎 Medium: https://medium.com/@sergeyleschev

🖨️ PDF: Download

ALT: SIARHEI LIASHCHOU

ALT: СЕРГЕЙ ЛЕЩЕВ

Pinned Loading

  1. react-custom-hooks react-custom-hooks Public

    React Custom Hooks @ S.Leschev: useArray useAsync useClickOutside useCookie useCopyToClipboard useDarkMode useDebounce useDebugInformation useDeepCompareEffect useEffectOnce useEventListener useFet…

    JavaScript 578 125

  2. leetcode-typescript leetcode-typescript Public

    TOP 200 #Dev 🏆 LeetCode, Solutions in TypeScript, Shell, Database (T-SQL, PL/SQL, MySQL), Concurrency (Python3). @ S. Leschev. Google Engineering Level: L6+

    TypeScript 13 2

  3. social-network social-network Public

     Social Network in SwiftUI with MVVM (Mobile + Back). Firebase for Login/Register. @ S. Leschev. Google Engineering Level: L6+

    Swift 61 7

  4. leetcode-swift leetcode-swift Public

    TOP 200 #Dev 🏆 LeetCode, Solutions in  Swift, Shell, Database (T-SQL, PL/SQL, MySQL), Concurrency (Python3). @ S. Leschev. Google Engineering Level: L6+

    Swift 63 13

  5. design-patterns design-patterns Public

     Design large-scale systems / 2022 / Design Patterns: Behavioral, Creational, Structural, etc. @ S.Leschev. Google Engineering Level: L6+

    Swift 39 7

  6. system-design system-design Public

    Design large-scale systems / 2022 / Amazon, Dropbox, Instagram, Facebook, Netflix, Pinterest, Twitter, Uber, Youtube architectures @ S.Leschev. L7+

    Jupyter Notebook 27 10