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Mahmoud Sayed
Verified Expert in Engineering
Software Developer
Cairo, Cairo Governorate, Egypt
Toptal member since June 1, 2021
Bio
Mahmoud is a senior software engineer and former competitive programmer with a bronze ACM medal. Since 2016, he has focused on building scalable, maintainable applications. His expertise covers Ruby on Rails, C++, Laravel, AWS, Terraform, PostgreSQL, Citus, Kafka, OpenTelemetry, and ECS. A tech-agnostic engineer, Mahmoud enjoys learning new tools and has a solid understanding of distributed systems, with experience in event-driven architectures.
Portfolio
Accredible
Ruby, Ruby on Rails (RoR), Elasticsearch, PostgreSQL, Sidekiq...
Egomotion OpCo Corp. dba Zeus Living Inc.
Ruby, Ruby on Rails (RoR), GraphQL, Agile, PostgreSQL, Ruby on Rails 7, Linux...
Corsair Gaming - Main
Ruby on Rails (RoR), PostgreSQL, AngularJS, Heroku, HTML, Sass, Scrum...
Experience
- Ruby on Rails (RoR) - 7 years
- Sidekiq - 7 years
- Ruby - 7 years
- Terraform - 2 years
- Elasticsearch - 2 years
- Amazon Web Services (AWS) - 2 years
- Citus - 2 years
- Amazon Elastic Container Service (ECS) - 1 year
Work Experience
Senior Back-end Engineer
2021 - PRESENT
Accredible
- Worked with the insights team to deliver a fast and reliable analytics dashboard with a distributed PostgreSQL database using the open-source Citus extension to build reliable rollup tables.
- Performed an optimization round for some of our services and APIs; made a CSV export service run 11x faster and three endpoints (EPs) run 2x more quickly.
- Designed and implemented a system that distributed a billing credit allowance between multiple organizations of the billing account to allow customized distribution of the credits.
- Designed and implemented the first consumers of our Kafka cluster along with the first monolith modular component in the Rails monorepo.
- Built a standardized system to integrate our solution easily and efficiently with any platform supporting LTI 1.3.
Technologies: Ruby, Ruby on Rails (RoR), Elasticsearch, PostgreSQL, Sidekiq, Amazon Web Services (AWS), Docker, Amazon OpenSearch, Apache Kafka, Amazon Kinesis, AWS Lambda, Amazon Elastic Container Registry (ECR), Amazon Elastic Container Service (ECS), Amazon RDS, Amazon Aurora, Amazon CloudWatch, AWS Elastic Beanstalk, Amazon S3 (AWS S3), Amazon MSK, Terraform, Citus, Amazon Simple Notification Service (SNS), Identity & Access Management (IAM), AWS WAF, Learning Tools Interoperability (LTI), APIs, Redis, Git, SQL, API Design, API Development, GitHub, Agile, Code Review, Redis Cache, Source Code Review, Back-end, CI/CD Pipelines, Distributed Systems, Event-driven Design (EDD), REST APIs, API Integration, Stripe API, Figma, Third-party APIs, Leadership, Technical Leadership, Ruby on Rails 7, DevOps, Linux, Python, Web Development, ActiveRecord, Object-relational Mapping (ORM)
Back-end (RoR) Developer
2021 - 2022
Egomotion OpCo Corp. dba Zeus Living Inc.
- Worked on a ClickUp integration to manage tasks, folders, and dependencies from within our web app.
- Made changes to the Auth implementation to improve it and integrated Devise Omniauth.
- Made changes to their GraphQL API and schemas by adding more attributes and queries.
- Helped to have more test coverage by adding both unit and request specs.
Technologies: Ruby, Ruby on Rails (RoR), GraphQL, Agile, PostgreSQL, Ruby on Rails 7, Linux, Web Development, ActiveRecord, Object-relational Mapping (ORM)
Ruby on Rails and PostgreSQL Developer
2021 - 2021
Corsair Gaming - Main
- Fixed multiple bugs that improved user experience.
- Added new features on the front and back end.
- Improved the performance and response time of existing endpoints.
Technologies: Ruby on Rails (RoR), PostgreSQL, AngularJS, Heroku, HTML, Sass, Scrum, Ruby on Rails 7, Linux, HTML5, Web Development, ActiveRecord, Object-relational Mapping (ORM)
Back-end Engineer
2019 - 2020
Iubenda
- Enhanced the response time to load help posts four times faster.
- Automated internal cache purging processes for fragment cache keys.
- Made pages load 10x faster by optimizing SQL queries and using cache.
- Built and implemented the back end of many features, such as the licensing system and multi-user accessibilities.
- Maintained integrations of 3rd-party billing gateways like PayPal and Braintree.
- Refactored multiple back-end parts, fixed bugs, and reviewed dozens of features and PRs.
Technologies: Ruby, Ruby on Rails (RoR), MySQL, Redis, Vue, Amazon Web Services (AWS), HTML, Docker, APIs, Sidekiq, Git, JavaScript, SQL, API Design, API Development, GitHub, GitLab, Agile, Code Review, Redis Cache, Amazon S3 (AWS S3), Amazon CloudWatch, Amazon Aurora, Amazon RDS, Source Code Review, Full-stack, Back-end, REST APIs, API Integration, PayPal API, Braintree SDK, Third-party APIs, Ruby on Rails 7, Bootstrap, Linux, jQuery, HTML5, Web Development, ActiveRecord, Object-relational Mapping (ORM)
Back-end Engineer
2018 - 2018
Femtodev
- Implemented the back end of ECare's API for caregivers.
- Implemented the back end of ECare's API for Alzheimer's patients.
- Managed the implementations and deployment for all back-end features.
Technologies: Ruby, Ruby on Rails (RoR), Heroku, HTML, APIs, Sidekiq, Git, SQL, API Design, API Development, GitHub, Code Review, Amazon S3 (AWS S3), Source Code Review, Back-end, REST APIs, API Integration, Ruby on Rails 7, Web Development, ActiveRecord, Object-relational Mapping (ORM)
Software Developer
2016 - 2017
Lifeblink
- Enhanced the database reads time by rewriting efficient queries and redesigning indexes what enhanced the application response time.
- Applied caching to the application so it can respond faster for the static views and the views visited before.
- Enhanced the application pagination by implementing infinite scrolling using Ajax instead of issuing another request and reloading the page.
- Designed and built the Life Group feature from scratch.
- Implemented the payment process for organizations. Used Active Merchant.
- Worked on the application API and enhanced its response time, enhancing DB queries and caching. Also, fixed multiple design and logic issues.
Technologies: Ruby, Ruby on Rails (RoR), Redis, CoffeeScript, JavaScript, Haml, MySQL, SCSS, CSS, HTML, APIs, Sidekiq, Heroku, Git, SQL, API Design, API Development, GitHub, Code Review, Redis Cache, Amazon S3 (AWS S3), Source Code Review, Full-stack, Back-end, REST APIs, API Integration, Ruby on Rails 7, Bootstrap, Linux, jQuery, HTML5, Web Development, ActiveRecord, Object-relational Mapping (ORM)
Project History
ECare
Developed a mobile application that eases the lives of patients suffering from chronic disease using technology. It notifies them of their doctor’s appointments and reminds them to take their medication. It also allows their caregivers to monitor their appointments and movements.
Accredible
https://accredible.com/A high-scale and distributed system application that issues digital certificates and badges for learners. I worked as a back-end engineer and have developed multiple features across various domains, contributing to the design, implementation, and maintenance of scalable and robust back-end systems. I also worked extensively with APIs, databases, and 3rd-party integrations to enhance the platform's functionality, ensuring reliability and performance. Additionally, my responsibilities included optimizing back-end processes, managing complex data models, and implementing new functionalities to support Accredible's mission of providing secure and verifiable credentials. I also collaborated with cross-functional teams to deliver high-quality solutions and continuously improve the platform's architecture.
Iubenda
https://www.iubenda.com/iubenda is a leading compliance automation platform where I worked as a back-end engineer. During my time there, I optimized the platform by improving the response time of help posts by 4x and automating internal cache purging processes. I significantly reduced page load times by 10x through query optimization and effective caching strategies. I played a key role in developing core features, such as the licensing system and multi-user accessibility, while maintaining third-party billing integrations with PayPal and Braintree. Additionally, I refactored back-end components, resolved critical bugs, and conducted thorough reviews of features and pull requests.
Education
2012 - 2017
Bachelor's Degree in Computer Engineering
Faculty of Engineering Shoubra, Benha University - Cairo, Egypt
Certifications
MAY 2017 - PRESENT
Certification of Achievement
ACM ICPC
JULY 2014 - PRESENT
Mobile Application Development
IBM
Skills
Libraries/APIs
Sidekiq, REST APIs, ActiveRecord, API Development, Vue, PayPal API, Stripe API, React, jQuery
Tools
Git, GitHub, GitLab, Amazon OpenSearch, Amazon Elastic Container Registry (ECR), Amazon Elastic Container Service (ECS), Amazon CloudWatch, Terraform, Citus, Amazon Simple Notification Service (SNS), Braintree SDK, Observability Tools, Capistrano, Figma
Languages
Ruby, HTML, JavaScript, SQL, HTML5, CoffeeScript, Haml, C++, GraphQL, SCSS, CSS, Sass, Python
Frameworks
Ruby on Rails (RoR), Ruby on Rails 7, Swagger, AngularJS, Bootstrap
Paradigms
Object-relational Mapping (ORM), Agile, Event-driven Design (EDD), Scrum, DevOps
Storage
MySQL, PostgreSQL, Redis, Elasticsearch, Amazon Aurora, Amazon S3 (AWS S3), Redis Cache
Platforms
Heroku, Amazon Web Services (AWS), AWS Lambda, Linux, Docker, Apache Kafka, AWS Elastic Beanstalk
Other
APIs, Code Review, Source Code Review, Back-end, API Integration, Web Development, Data Structures, API Design, Full-stack, CI/CD Pipelines, Third-party APIs, Amazon Kinesis, Amazon RDS, Amazon MSK, Identity & Access Management (IAM), AWS WAF, Learning Tools Interoperability (LTI), Distributed Systems, OpenTelemetry, Leadership, Technical Leadership
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