Wael Almattar, Developer in New York, NY, United States
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Wael Almattar

Verified Expert  in Engineering

Architect and Developer

Location
New York, NY, United States
Toptal Member Since
October 1, 2020

Wael is a senior software engineer and back-end and blockchain developer with 10 years of experience in architecture, back-end services, APIs, and decentralized apps in the Web3 space. He pays special attention to performance, scalability, and architecture design. Thanks to a proactive attitude, an open mind, and an entrepreneurial spirit, Wael has managed international and distributed teams to deliver products on time and within budget.

Back-end DevelopmentBack-endNode.jsJavaScriptAmazon Web Services (AWS)ReactTypeScriptKoaGoAmazon DynamoDBGraphQLMicroservicesComputer ScienceAlgorithmsWeb ProgrammingIntercom

Portfolio

Klarna
Node.js, TypeScript, Amazon Web Services (AWS), Microservices, Apache Kafka...
Zalando
Node.js, TypeScript, Amazon Web Services (AWS), NPM, Microservices, Storybook...
Anheuser-Busch
Node.js, TypeScript, React, GRAPH, REST APIs, Apache Kafka, Microservices...

Experience

Node.js - 6 yearsAPI Integration - 5 yearsGo - 4 yearsTypeScript - 4 yearsMicroservices - 3 yearsGraphQL - 3 yearsBlockchain - 1 yearCosmos SDK - 1 year

Availability

Part-time

Preferred Environment

Amazon Web Services (AWS), SQL, TypeScript, REST APIs, Microservices, Node.js, Go, Ethereum Smart Contracts, Solidity, Cosmos SDK

The most amazing...

...project I've done was designing and implementing a platform that serves more than 12,000 companies and 100,000 users.

Work Experience

Senior Back-end Engineer

2021 - 2022
Klarna
  • Worked in a team of eight people to develop and maintain browsers within the Klarna application.
  • Took responsibility for the back-end infrastructure of the back-end facing front-end layer and internal service to serve Klarna users.
  • Used Node.js and TypeScript to develop and maintain back-end services that handle more than 10 million daily requests.
  • Wrote testable, documented code that was highly maintainable.
  • Ensured maximum performance, compatibility, and world-class user experience across devices and form factors.
  • Stayed up to date on emerging technologies and frameworks.
Technologies: Node.js, TypeScript, Amazon Web Services (AWS), Microservices, Apache Kafka, Redis, Axios, Back-end Development, Solution Architecture, Go, Mobile Back-end, eCommerce APIs, Amazon DynamoDB, Terraform

Senior JavaScript Engineer

2020 - 2020
Zalando
  • Used modern web technologies and frameworks to develop front-end distribution systems for components and libraries across the whole retail center.
  • Wrote testable, documented code that was highly maintainable.
  • Developed for maximum performance, compatibility, and a world-class user experience across all devices and form factors.
  • Collaborated with UI/UX designers to improve usability and accessibility.
  • Automated repetitive tasks when possible, using customized scripts.
Technologies: Node.js, TypeScript, Amazon Web Services (AWS), NPM, Microservices, Storybook, Antd, GraphQL, Back-end Development

Lead Software Engineer and Architect

2019 - 2020
Anheuser-Busch
  • Spearheaded the back-end infrastructure development for a new payment service in the Southern American region with an expected 1 million daily users.
  • Designed the overall back-end framework, specifically security, documentation, deployment, testing, etc.
  • Implemented an e-wallet, single-page application with React and Webhooks.
  • Created checkout components for external usage by customers and published them to the npm library.
  • Collaborated with a team of ten developers to implement back-end services by GraphQL.
  • Worked with the rest of the squad and external service providers to ensure the back-end services needed in each iteration were delivered.
  • Ensured that the pace of delivery was protected by applying best engineering practices.
  • Offered a strategic direction on best design practices.
  • Provided updates to date documentation at every stage of development.
Technologies: Node.js, TypeScript, React, GRAPH, REST APIs, Apache Kafka, Microservices, Azure, Azure Cloud Services, Kubernetes, NoSQL, MongoDB, Payment APIs, Payment Processing, Fintech, PostgreSQL, Architecture, Back-end Development, Solution Architecture, IT Product Management, Back-end Architecture, Cloud Architecture, IT, AWS Lambda, Amazon DynamoDB, Terraform

Lead Back-end Developer

2018 - 2019
Yara
  • Worked with engineering managers to construct the new team to build a new platform used by the Yara sales team in more than ten countries.
  • Constructed a project with TypeScript, GraphQL, and caching, using Redis on the back end and React with hooks and Material-UI on the front end.
  • Consulted the business team to draw a reliable roadmap.
  • Worked mainly as a back-end developer during my time here.
  • Interviewed candidates for permanent roles to continue working on the project.
  • Worked with the SRE team to ship deployments with CircleCI, Docker, and Kubernetes.
Technologies: Amazon Web Services (AWS), Unit Testing, Auth0, SQL, Kubernetes, Docker, Material UI, Elastic, Redis, GraphQL, TypeScript, Node.js, Back-end Development, IT Project Management, AWS Lambda

Lead Back-end and Microservices Engineer

2017 - 2019
Techloop
  • Developed the back end for a platform that serves 100,000 users and 12,000 companies.
  • Took responsibility as a lead programmer for the whole back-end infrastructure, including microservices and RESTful APIs.
  • Proposed a simplified but scalable system architecture that is being used at the moment in the production environment.
  • Introduced GraphQL to the platform and worked with the front-end team to integrate it.
  • Used automated solutions to accelerate the development process.
  • Extended the existing API with more features and functionalities.
  • Tracked tasks, features, and bugs with Jira and Asana.
  • Implemented a data-driven approach to support the marketing and sales teams.
  • Created a one-page application using React and custom components on top of MUI v4.
  • Worked with the business development manager on breaking down new business models into realistic technical tasks with a clear roadmap.
Technologies: Auth0, SQL, PostgreSQL, RESTful Development, REST APIs, APIs, Cron, Git, Koa, AMQP, RabbitMQ, React, GraphQL, Microservices, Go, Node.js, Google Ads API

React Developer

2017 - 2017
International Committee of the Red Cross (via Iosbar Blue Infinity)
  • Developed a custom CRM system for the International Committee Red Cross.
  • Tracked features and fixed bugs using Microsofts TFS platform and Microsoft PBI. The platform has been launched successfully and has been in production used internally by ICRC.
  • Provided full unit testing and clear documentation.
Technologies: Git, Amazon Web Services (AWS), Jest, TypeScript, Node.js, React

Full-stack Developer

2017 - 2017
Dether.io
  • Implemented a single-page, live-map platform to show users and shops.
  • Extended the API for the Dether.io platform with a couple of endpoints.
  • Formulated and documented technical architecture, components, and strategies for mitigating technical challenges.
Technologies: Git, React Native, Google Maps, Mapbox, Redux Form, Jest, Redux, React, Node.js

Full-stack Developer

2016 - 2017
VariSolutions
  • Worked part-time with the core team to grow the main back-end server using Node.js.
  • Implemented new features and pages using React for A/B testing software.
  • Wrote unit, end-to-end, and integration tests using Mocha and Jest.
  • Optimized the performance by moving aggregated data to Redis server storage.
  • Implemented an A/B testing solution to determine the better-performing variations.
Technologies: Mocha, Git, Heroku, Redux, Testing, Jest, Express.js, Redis, Node.js, React

Software Engineer

2015 - 2016
Globe IT
  • Designed a complete tracking system for GPS tracking devices with a live real-time dashboard using Node.js, Socket.IO, and AngularJS.
  • Created and designed a decoder server to handle a GPS binary device’s data and send commands.
  • Optimized a web application's speed and data structures by combining Memcached and MySQL databases.
  • Led the API development of a new eCommerce/digital platform (PHP and Node.js).
  • Designed a dashboard along with a complete solution for a chat module for an eCommerce project using PHP and AngularJS.
  • Maintained existing eCommerce and digital applications to meet the ever-evolving demands of the business (PHP).
  • Implemented an online payment system for eCommerce services.
  • Developed from scratch an interactive web conference video platform that hosted video rooms with text and voice capabilities using WebRTC, Socket.IO, and jQuery.
  • Used AngularJS as the development framework to build a dashboard, a single-page application, and a more interactive front end.
  • Developed a web-scraping application along with the entire server-side application using Python.
Technologies: SQL, Git, C++, Loopback, WebRTC, Python, MySQL, Zend Framework, jQuery, CSS, PHP, Redis, Express.js, Socket.IO, AngularJS, Node.js, Back-end

Web Developer Intern

2014 - 2014
Mamania.pl
  • Worked on various projects where more experienced, senior developers guided me.
  • Integrated and tested an online payment system to the eCommerce platform.
  • Worked primarily as a full-stack developer as part of my bachelor's degree thesis.
Technologies: CSS, SQL, JavaScript, PHP, Zend Framework

Back-end Infrastructure for Two APIs and Six Microservices

https://techloop.io
As the lead back-end developer, I was responsible for rewriting one API and extending the features on the other one along with six microservices connected to third-party solutions. I introduced scalable, modern technologies implemented and used nowadays in production to serve more than 100,000 daily users.

Lead Back-end Consultation

I proposed and led the development of a back-end infrastructure of a nutrition plan generation platform used by the sales team at an $8-billion valued fertilizer producing company (a company that was established in 1905). The back end was integrated with an already existing agronomical engine and SSO authentication service.

GEO2 | Live Tracking System for Cars, People, or Animals

http://geo2.pl/
For this project, I first built a back-end server that decodes binary signals from geolocation devices. Then I implemented a single-page application to show real-time data on maps. The application was designed both for web and mobile devices. The platform supports multiple users per partner and also has an online payment system.

The devices and platform are used by more than 20 partner companies.

Languages

GraphQL, TypeScript, JavaScript, HTML, Go, C++, SQL, C, Python, PHP, CSS, Solidity

Frameworks

Koa, AngularJS, Express.js, Zend Framework, Loopback, Jest, Redux, React Native, Material UI, Angular, Tendermint

Libraries/APIs

Node.js, React, Slack API, Socket.IO, React Redux, Google Ads API, jQuery, WebRTC, Redux Form, Google Maps, AMQP, Objection.js, Segment.io, REST APIs, Antd

Paradigms

Microservices, Microservices Architecture, RESTful Development, Unit Testing, Automation, Management, Testing, Back-end Architecture

Platforms

Amazon Web Services (AWS), Algolia, HubSpot, AWS Lambda, Heroku, Mapbox, Docker, Kubernetes, Apache Kafka, Azure, Blockchain

Storage

Amazon DynamoDB, Redis, MySQL, PostgreSQL, Azure Cloud Services, NoSQL, MongoDB

Other

APIs, Back-end, Back-end Development, API Integration, Computer Science, Algorithms, Web Programming, Software Engineering, Data Structures, RESTful Microservices, Code Auditing, Cryptography, Machine Learning, Data Analytics, Mobile App Development, Space Dynamics, Communication, Custom Instruments, Space Physics, Artificial Intelligence (AI), Electronics, Astrophysics, Image Processing, Microcomputers, Intercom, Full-stack, GRAPH, Payment APIs, Payment Processing, Fintech, Storybook, Axios, Cosmos SDK, Architecture, Solution Architecture, Ethereum Smart Contracts, eCommerce, Mobile Back-end, eCommerce APIs, IT Product Management, Cloud Architecture, IT, IT Project Management

Tools

Git, RabbitMQ, Cron, CircleCI, Slack, Terraform, Elastic, Mocha, GIS, Auth0, NPM

2016 - 2017

Joint Master's Degree in Space Science and Technology

Université Paul Sabatier Toulouse III - Toulouse, France

2016 - 2016

Completed Credits Towards a Joint Master's Degree in Space Science and Technology

Luleå University of Technology - Kiruna, Sweden

2015 - 2016

Completed Credits Towards a Joint Master's Degree in Space Science and Technology

The Julius Maximilians University of Würzburg - Würzburg, Germany

2012 - 2015

Bachelor's Degree in Computer Science

Warsaw University of Technology - Warsaw, Poland

NOVEMBER 2012 - PRESENT

Fifth Place in a Collegiate Programming Contest

ACM

SEPTEMBER 2010 - PRESENT

Bronze Medal

International Olympiad in Informatics (IOI)

Collaboration That Works

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