Khaled Osman, Developer in Berlin, Germany
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Khaled Osman

Verified Expert  in Engineering

Full-stack Developer

Berlin, Germany
Toptal Member Since
December 29, 2021

Khaled is a software engineer specializing in technical leadership, architecture, mentorship, and everything concerning JavaScript development. He's been working in the industry for 8+ years with multiple startups as their first tech hire and has led teams and built many applications from scratch during that period. Khaled's main areas of expertise and preferences are software architecture, web performance, serverless, full-stack development, consulting, and mentorship.


Ruby, Ruby on Rails 4, GraphQL, React, TypeScript
NestJS, React, Node.js, Amazon Web Services (AWS), GraphQL, MongoDB, PostgreSQL...
Ionic, Vue, Vuex, Node.js, TypeScript, Amazon Web Services (AWS)




Preferred Environment

React, Vue, Stencil.js, Node.js, NestJS, GraphQL, Docker, MongoDB, Serverless, Amazon Web Services (AWS)

The most amazing...

...thing I take pride in is building software architecture and systems from scratch, teaching software engineering and automating things.

Work Experience

Senior Software Engineer

2022 - 2023
  • Worked and shipped three projects and managed to work cross-stack on both the back end and front end despite being hired as a back-end developer in the Shopify engineering culture that is strict discipline focused.
  • Developed the new self-serve returns feature allowing customers to initiate returns to merchants.
  • Established the latest structured return policies project allowing merchants to create and configure their return policy, determining which items are eligible for return and which aren't.
  • Worked on public APIs for returns allowing 3P apps and 3P developers to call Shopify APIs to create returns and dispositions.
Technologies: Ruby, Ruby on Rails 4, GraphQL, React, TypeScript

Lead Engineer

2021 - 2022
  • Screened, interviewed, and hired new team members to grow the team.
  • Migrated the company's microservices and different apps into a mono repository structure.
  • Set up all engineering-related processes for product and tech, and ensured the teams' needs were met, and feedback was heard.
  • Maintained code quality and learning environment through code reviews.
  • Turned product and design ideas into architecture diagrams and technical tickets for developers to understand and work on.
  • Set up versioning and release strategy throughout the product lifecycle.
  • Improved overall app performance through best practices and converted the application into an offline-first progressive web app that works offline and on slow internet connections.
Technologies: NestJS, React, Node.js, Amazon Web Services (AWS), GraphQL, MongoDB, PostgreSQL, Docker

Senior Full-stack Engineer

2020 - 2021
  • Maintained and added new features to their old app as the first hire on the team.
  • Implemented their new hybrid web and mobile app from scratch using Vue 3, Capacitor, and Ionic as a PWA.
  • Defined and implemented automated releases and versioning strategy along with their CI/CD pipelines.
  • Implemented biometric authentication for the app along with data visualisations that show the user's account balance over time.
Technologies: Ionic, Vue, Vuex, Node.js, TypeScript, Amazon Web Services (AWS)

Full-stack Engineer

2018 - 2020
  • Collaborated with the head of engineering to build customer projects as their first hire on the back-end team.
  • Joined weekly client meetings to gather requirements from clients and update them on the ongoing development progress.
  • Took over entire client projects from architecture, planning, and technology decisions all the way through implementation and delivery.
  • Wrote technical specifications for planned new features and managed external back-end development team for one of the projects to ensure quality and feature delivery.
  • Implemented and delivered eight different IoT client projects both for other startups as well as big companies.
Technologies: Node.js, React, Azure, Amazon Web Services (AWS), GraphQL, Serverless, TypeScript, Serverless Framework, Redux, Vue, Docker, PubNub, MongoDB, Redis, Stencil.js

Senior Software Engineer

2015 - 2018
  • Worked directly with the CTO to build their new software as their first hire in the Berlin dev team.
  • Built the new version of the product front end from scratch.
  • Made and implemented multiple customizable and configurable customer projects based on the main core product.
  • Ran internal workshops and presentations to showcase new technologies and teach new technologies to the development team.
  • Built multiple real-time, interactive, dynamic, and configurable visualizations using D3.js.
  • Implemented CLI to build, deploy, and undeploy any client projects and set up automated deployment, testing, and internal continuous integration project as a web app for easy one-click deployments as well as version and status monitoring.
  • Refactored and migrated the codebase into newer technologies and got rid of technical debt to ensure maintainability.
  • Implemented microservices and back-end APIs to recommend data to the users.
Technologies: D3.js, Gulp, Webpack, Angular, AngularJS, jQuery, React, GraphQL, Node.js, Docker, Serverless, MongoDB, RxJS, Amazon Web Services (AWS)

Vantik Card

A hybrid mobile and web app that automatically manages users' pension savings accounts along with a credit card that adds 1% cashback on every purchase to their savings accounts.

I was mainly responsible for web and mobile app development as the only person on the front-end team.

Carbon Emission Tracking for Businesses

A web application for businesses to calculate and analyze their Scope 3 carbon emissions hidden in their supply chain. I acted as an engineering lead on the project, maintaining the architecture, technical specifications, and code reviews.

Building Management

A web and mobile app that shows businesses the amount of air pollutants and air quality in each room of the building through IoT sensors, along with visualizations and historical data for the measurements over time.

I built both the back end and the front end for the app.

Ice Cream Vendors

An application that shows the user geographical locations of ice cream vendors moving on a bike nearby his location, using Google Maps capabilities and showing the direction and routes to get there.

I served as a full-stack engineer building both the back end and the web app.

Sports Game Tracking

A mobile app that allows users to see information and schedules of ongoing games for multiple sports such as NFL and NBA across multiple leagues, as well as real-time data information regarding live games such as scores, ball position, game clock, game period, ball possession, bets, and odds.

The app also had an "excitometer" that ranked games by how exciting each game was and sent notifications about ongoing game scores to users in real time, both as app notifications and via SMS, depending on user preferences.

I served as a back-end engineer setting up the infrastructure and architecture to gather all the related information from different APIs as well as another back-end API that publishes real-time data to the mobile app.

Portable Mobile Wifi Hotspot

A hardware and a mobile app that allows users to connect to the internet and take photos from anywhere over the world. I acted as a back-end and firmware engineer developing the back-end API that interacts with the firmware to connect or disconnect from the internet as well as take and save photos and upload them to Dropbox.

Smart Dishwasher Cleaning

Sensor-based hardware that can smartly dispense the needed amount of liquid for each wash cycle, depending on the configuration. It also shows information about the ongoing wash cycle, the estimated time left, and when you need to replenish the liquid.

I served as a back-end engineer creating the APIs both for the firmware needing to send and store device-related events as well as the mobile application where the user needs to see all related information and an activity stream facilitating the communication between both the mobile app and the hardware device.

Coffee Ordering App

A web app that allows users to order coffee from a nearby coffee shop and see real-time information regarding their order readiness so that they can pick it up once ready.

I served as a full-stack engineer building both the back-end API and the front-end app.

Innovation Management CMS Software

An application for businesses that digitalizes innovation management by adding their content, data about ongoing trends, technologies, markets, and any data relevant to their business industry through a custom-built CMS. It also enables collaboration on the data through sharing, rating, commenting, real-time interactive data visualizations, and technology radars to determine the business needed course of action or areas of interest.


GraphQL, TypeScript, JavaScript, HTML, Java, CSS, Ruby


Ionic, Serverless Framework, Angular, Express.js, Vanilla JS, NestJS, Redux, AngularJS, YARN, Next.js, Ruby on Rails 4


React, Vue, Node.js, Vuex, PubNub, D3.js, jQuery, RxJS, Google Maps, Socket.IO


Stencil.js, Webpack, NPM, Git, Amazon Elastic Container Service (Amazon ECS), Amazon Simple Queue Service (SQS), Amazon Simple Email Service (SES), AWS Simple Notification Service (SNS), Firebase Cloud Messaging (FCM), Gulp, Android Studio, Xcode, Lerna, Google Cloud Messaging


Offline-first Development


Docker, AWS Lambda, Amazon Web Services (AWS), Azure, Android, Azure Functions


MongoDB, Redis, Amazon S3 (AWS S3), Amazon DynamoDB, PostgreSQL, Azure Cosmos DB


Serverless, Progressive Web Applications (PWA), Mentorship & Coaching, Team Leadership, Technical Leadership, Performance Tuning, Front-end, Back-end, User Interface (UI), Architecture, System Architecture, Leadership, Full-stack Development, Internet of Things (IoT), Storybook

2009 - 2014

Bachelor's Degree in Computer Science and Engineering

German University Of Cairo - Cairo, Egypt