Samuel is available for hire
Hire SamuelSamuel Bohn
Verified Expert in Engineering
Full-stack Developer
Location
Strasbourg, France
Toptal Member Since
April 21, 2020
Samuel is passionate about open-source technologies and automation. He builds applications with a focus on maintainability, efficiency, and simplicity. With a technology-agnostic mindset, Samuel genuinely wants to understand his client's core business and solve their problems using the most relevant technologies.
Portfolio
Freelance
Rancher, GitLab, GraphQL, REST, PostgreSQL, Docker, React, Django...
Print Speak, subsidiary of MBE Worldwide
Ruby on Rails (RoR), PostgreSQL, Docker, ETL, JavaScript, Architecture
Early Staging Company in South East Asia ( NDA )
Python, Django, GraphQL, React, PostgreSQL
Experience
Availability
Part-time
Preferred Environment
Terminal, MacOS, Visual Studio Code (VS Code)
The most amazing...
...thing I've designed and developed is a real time multi level marketing and commission system.
Work Experience
Full-stack Engineer
2018 - PRESENT
Freelance
- Worked as a subcontractor for software development agencies providing time and cost-efficient software development services. The specific details of this project are covered by an NDA.
- Refactored strategic monolith features into REST microservices using Ruby, Python, and Go with JWT asymmetric encryption. An NDA covers the work for the product.
- Built a WebSocket micro-service twice using Go for real-time communication as a highly performant replacement to Ruby on Rails action cable before the gem AnyCable-Go existed. Additional details are covered under an NDA.
- Implemented CI pipelines and deployed applications to production.
- Fixed common problems such as performance issues due to N+1 queries, hidden bugs due to duplicated data, and security issues.
- Worked on new and existing projects, always striving for time and cost-efficient solutions regarding the existing codebase or infrastructure.
- Built and integrated interactive React components in several server-side rendered full-stack Ruby on Rails and Django applications.
- Constructed a corporate intranet application with internal web services integration using Rails API mode with a React SPA front-end (NDA).
- Performed maintenance work on existing Ruby on Rails applications, such as adding new features, fixing bugs and performance issues, and upgrading Ruby/Rails versions.
Technologies: Rancher, GitLab, GraphQL, REST, PostgreSQL, Docker, React, Django, Ruby on Rails (RoR), Ruby, Next.js, GitLab CI/CD, JavaScript, Full-stack, Go
Ruby on Rails Back-end Engineer
2020 - 2020
Print Speak, subsidiary of MBE Worldwide
- Designed the Print Speak CRM/BI commercial printing SaaS integration and customization with MBE Hub Logistic and fulfillment proprietary ERP solution deployed across a franchisee network of 3000+ locations in 50+ countries.
- Developed a POC validated by the board of MBE Worldwide by integrating specific sections of Print Speak.
- Enabled the start of a several-year product design and integration cycle whose success will multiply the Print Speak customer base by six by serving it directly to MBE Worldwide franchisees.
- Developed the ETL process for the MBE API using incremental atomic updates.
- Reduced the Ruby on Rails application technical debt, upgraded critical dependencies, increased test coverage, and performed targeted refactoring.
Technologies: Ruby on Rails (RoR), PostgreSQL, Docker, ETL, JavaScript, Architecture
Back-end Engineer
2019 - 2020
Early Staging Company in South East Asia ( NDA )
- Built several features as an individual contributor.
- Created a real-time atomic multilevel marketing commission system by leveraging native PostgreSQL recommended queuing features.
- Reviewed all migrations before deployment to production.
- Audited and secured the GraphQL API from data leaks and DDoS attacks.
- Mentored front-end, back-end, and mobile teams ensuring cross-team collaboration in a cross-cultural and international environment.
Technologies: Python, Django, GraphQL, React, PostgreSQL
Full-stack Developer
2016 - 2017
Strasbourg University
- Maintained and added new features to a document management system and an onboarding platform to track several universities' apprentices reporting requirements.
- Designed, developed, and deployed a poll application integrated with existing systems.
- Built, designed, and deployed a collaborative grade management system integrated with existing systems and used until today by thousands of daily users.
- Fixed long-term issues by doing targeted refactoring and adhering to SSOT.
- Communicated directly with various stakeholders, including Strasbourg University and the representative of another public institution.
- Implemented the Agile methodology by working in sprints, communicating with the client in the development process, prioritizing features, and meeting deadlines.
Technologies: WebSockets, jQuery, Symfony, Django, Django Channels, Bootstrap, JavaScript, MySQL, PostgreSQL
Ruby on Rails Full-stack Developer
2015 - 2015
Idéematic Web Agency
- Built a cooptation-only professional Ruby on Rails social network targeting a specific audience; this was a startup MVP.
- Implemented core features of the Ruby on Rails application, including the business logic and social network features like follows, likes, timeline, friends, and a search engine using Sphinx.
- Performed small maintenance tasks on other projects.
- Mentored other interns regarding Git and Ruby on Rails usage and the project conventions.
Technologies: Git, Redmine, jQuery, Sass, Haml, Sphinx Search Engine, RSpec, Ruby on Rails (RoR), Ruby, JavaScript
Experience
Lean ERP Solution for Freelancers and Micro Enterprises
https://www.leany.io/A multi-tenant software as a service application with basic CRM, inventory management, and opportunity management capabilities targeting sole proprietorships, micro-enterprises, and emerging-market SMEs.
I am collaborating with industry professionals and entrepreneurs to automate their business flows. As the sole developer, I built a technological foundation to design industry-specific integrations starting with real estate. This foundation includes:
• custom domains
• tenant and domain-based data scoping
• field level authorization
• filters and order by generators
• custom GraphQL data loaders for one-to-many/many-to-many and polymorphic relations
• API caching
• dynamic forms generators
• different UI per integration based on the same app
• a multi-platform and brandable client with 100% code sharing using Next.js and PWA technology
• reusable React components following Atomic Design principles
This is an ongoing project.
I am collaborating with industry professionals and entrepreneurs to automate their business flows. As the sole developer, I built a technological foundation to design industry-specific integrations starting with real estate. This foundation includes:
• custom domains
• tenant and domain-based data scoping
• field level authorization
• filters and order by generators
• custom GraphQL data loaders for one-to-many/many-to-many and polymorphic relations
• API caching
• dynamic forms generators
• different UI per integration based on the same app
• a multi-platform and brandable client with 100% code sharing using Next.js and PWA technology
• reusable React components following Atomic Design principles
This is an ongoing project.
Deal Aggregation Platform
A Ruby on Rails and React web app I built in 2018 for showing deals aggregated from consumer marketplaces providing the user a feeling of walking around a store while searching for colored deals tags. After applying to several marketplace developer programs, I was accepted to eBay Partner Network. I designed a simple ETL process to synchronize prices every hour. I terminated the project after the API I was using had been deprecated.
Grade Management System
A Django and WebSocket-based app I built in 2017 to allow university professors to efficiently design and schedule exams according to yearly modeling legal requirements, proceed collaboratively on grade entry, and provide real-time grade average computation and other metrics. User information and modeling data are retrieved from a third-party internal API without duplicating any data. It simplifies the process for professors and allows students to have their grades in real-time.
Rails and Go Game Back-end
https://github.com/3pns/acrobatt-game-serverI built a Ruby on Rails and Go back-end as my final project for my bachelor's degree in 2016-2017, where my teammate worked on the front end. The user login and data are persisted through a Rails data REST API. The main lobby, game lobby, and real-time game communication are done through a Go WebSocket server using Go channels.
Skills
Frameworks
Ruby on Rails (RoR), Django, JSON Web Tokens (JWT), Next.js, Symfony, Unity, Redux, Unity3D, Bootstrap, Django Channels, Cypress, Material UI, Tailwind CSS
Libraries/APIs
React, Graphene-Django, jQuery, Sockets, Node.js
Other
Full-stack, WebSockets, APIs, Processing & Threading, Sagas, Architecture, Software Engineering, Distributed Systems, Progressive Web Applications (PWA), Cloudflare, Languages, Atomic Design
Languages
Ruby, Python, GraphQL, JavaScript, TypeScript, Go, Haml, Sass, C#, HTML5, CSS3, SCSS, HTML, SQL, CSS
Tools
Git, Sublime Text, Terminal, GitLab CI/CD, GitLab, RSpec, Redmine, Helm
Paradigms
REST, Agile, DRY, KISS, Requirements Analysis, Test-driven Development (TDD), ETL, DevOps
Storage
PostgreSQL, Sphinx Search Engine, Redis, MySQL, JSON
Platforms
Docker, Rancher, Linux, MacOS, Alpine Linux, Debian, Kubernetes, Google Cloud Platform (GCP), Visual Studio Code (VS Code)
Industry Expertise
Project Management
Education
2016 - 2017
Bachelor's Degree in Computer Science
University of Strasbourg - Strasbourg, France
2013 - 2016
Associate's Degree in Computer Science
University of Strasbourg - Strasbourg, France
2011 - 2013
Course in Japanese Language
Shinjuku Japanese Language Institute - Tokyo, Japan
Certifications
JANUARY 2015 - PRESENT
Japanese-Language Proficiency Test N3
The Japan Foundation
Collaboration That Works
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