David Gasana Manzi

Summary

David is a full-stack software engineer and the Managing Director at One World Coders Rwanda Ltd. With nearly 5 years of professional experience, David excels in developing high-quality, maintainable code for complex web applications. He is passionate about clean code, cultural intelligence, and agile methodologies. David is committed to continuous learning and professional growth, making him an asset to any team/project he is engaged in.

Availability

Immediately

Education

• 2016 - Bachelors, Computer & Software Engineering, University of Rwanda - College of Science & Technology
• 2021 - Apprenticeship at One World Coders with Li-Hsuan Lung

Programming Languages

• Ruby(Practicing)
• Python(Practicing)
• Javascript(Practicing)
• C#(Practicing)
• Golang(Learning)

Framework Experience

• Ruby on Rails(practicing)
• Reactjs(Practicing)
• Node.js(Practicing)
• ExpressJs(Practicing)
• Django(Practicing)
• Angular(Practicing)
• React Native(Practicing)
• Flutter(Practicing)
• Vue.js(Practicing)
• Django(Practicing)
• Next.js(Practicing)
• NestJs(Learning)

Database Experience

• PostgreSQL(Practicing)
• MySQL(Practicing)
• MongoDB(Practicing)
• Redis (Practicing)

DevOps Experience

• Docker(Practicing)
• Heroku(Practicing)
• AWS(Practicing)
• Azure(Practicing)
• Circle CI(practicing)
• Travis CI(Practicing)
• Github Actions (Practicing)

Project Experience

Online Marketing Publication

It is a tool for publishing online magazines and have clients select offers the feel like need

• I worked on contenarization of the legacy code with docker
• Putting the legacy project under Continous Integration with Github actions

US-based Food Distributor

• Used Turnip a Gherkin extension of RSpec to write higher level (acceptance) tests
• Led multi-generation Rails upgrades (4 → 5 → 6) and Heroku stack upgrades to keep the platform on supported versions
• Built a homepage display mode toggle allowing admins to switch between postcard and product grid layouts
• Implemented a full-CRUD banner management feature for promotional content at the top of the page
• Configured AWS S3 via Active Storage for product image upload and randomized homepage display
• Added region-based signup restrictions and customer-type segmentation controlling brand and product visibility for direct customers
• Debugged silent order checkout failures by adding structured logging and propagating invoice creation errors correctly

Learning Outcome Matrix App

• It is an internal tool for managing the learning outcome matrices of apprentices at One World Coders
• Using Ruby on Rails to build the API functionality of the app
• Using good ol’ Capistrano to automate deployment on AWS EC2
• Using React library for the frontend side of the APP
• Using Redux for state management
• Using Jest and Enzyme for testing of the frontend

Artists Digital Portfolio Platform

• Contributed to the backend and frontend of a platform used by artists to create and manage their portfolios.
• Ensured seamless user experiences across the platform.
• Ensured SSL certifications of artist websites

Manufacturing Asset Marketplace

A full-stack platform for a manufacturing industry client — covering the public-facing inventory site (Rails), a .NET/C# REST API, and two Umbraco CMS deployments.

• Built the responsive inventory and asset-detail pages from Figma designs, including image zoom, breadcrumbs, and Markdown rendering
• Implemented catalog PDF generation and an asset quote flow with reCAPTCHA integration
• Built an AMP (Accelerated Mobile Pages) version of the inventory with full-text search
• Developed a consigner portal with admin CRUD, Azure Blob Storage for logo images, and MongoDB-backed data storage
• Added Brotli and Gzip compression, lazy-loaded images, and resolved WCAG accessibility issues
• Upgraded Ruby to 3.2.2 and resolved dependency conflicts introduced by the upgrade
• Fixed AMP consigner category pages returning 404 by adding a canonical tag bypass for categories outside the public index
• Built C# API endpoints for featured assets, catalog generation, consigner filtering, and PDF-based asset quotes
• Replaced a third-party HTML-to-PDF service with PuppeteerSharp (headless Chrome); diagnosed a WebSocket incompatibility between .NET Framework 4.8 and modern Chrome on Azure, then migrated to Gotenberg to fully resolve the issue
• Upgraded an Umbraco CMS from v7.4.0 to v7.15.11, resolving cascading dependency conflicts and CI pipeline failures
• Scaffolded a new Umbraco 13 CMS instance with Azure Blob Storage for media persistence and SQL-backed audit logging

Pastoral Resources Platform

A Rails-based platform for managing pastoral resources, ministry leads, and subscriber outreach.

• Led a full-site redesign implementing responsive layouts and a video-based “Getting Started” feature
• Set up CI/CD with GitHub Actions, including a Dockerised test environment with PhantomJS for acceptance tests
• Upgraded Rails from 4.2 to 5 and Node.js from 13.8 to 14; migrated the encryption gem to resolve security vulnerabilities
• Added CSV export for advertised lead data and fixed association query bugs using distinct

Survey and Reporting Tool

• Integrated Redux Toolkit for state management in a survey display and reporting application
• Added pie chart interactivity and refined report wording based on feedback