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Luca Nioi
Verified Expert in Engineering
Software Developer
Barcelona, Spain
Toptal member since May 19, 2022
Bio
Luca is a seasoned senior engineer and consultant with vast experience in startups and enterprises. He has mastered everything from Rails monoliths to Go microservices, supporting projects from small-scale to 30+ million monthly users. Proficient in Ruby, JavaScript, and Go, Luca writes clean, maintainable code for sustainable development. As a technical consultant for various startups, his deep understanding of code and business needs makes him an invaluable asset.
Portfolio
Skylark Travel Group, INC
Ruby, Ruby on Rails (RoR), PostgreSQL, Hotwire, Ruby on Rails 8, Stimulus...
Sempi Technology GmbH
Ruby on Rails (RoR), REST APIs, PostgreSQL, Amazon Web Services (AWS), DevOps...
Eleos Health
Python, Node.js, JavaScript, HubSpot, Salesforce, Salesforce Sales Cloud...
Experience
- Scalability - 6 years
- Optimization - 6 years
- Ruby on Rails (RoR) - 6 years
- Ruby - 6 years
- Node.js - 6 years
- Test-driven Development (TDD) - 4 years
- Agile - 4 years
- Go - 2 years
Preferred Environment
Node.js, Ruby, Agile, Go
The most amazing...
...thing I've done is design a cost-effective event-driven messaging system for handling large quantities of user data.
Work Experience
Ruby Developer
2025 - 2025
Skylark Travel Group, INC
- Simplified drastically a messy, over-engineered back-end system involving multiple services written in different languages to a unified Ruby on Rails back end.
- Oversaw the entire engineering department as an acting engineering manager once after my first month, serving the company as its senior-most technical staff member.
- Worked directly with the CEO and the managing partner to steer the company towards success.
Technologies: Ruby, Ruby on Rails (RoR), PostgreSQL, Hotwire, Ruby on Rails 8, Stimulus, Turbo, User Experience (UX), User Interface (UI), Front-end, Performance Optimization
Ruby on Rails Developer
2024 - 2025
Sempi Technology GmbH
- Architected a flexible data transformation pipeline that converts platform-agnostic product descriptions into platform-specific formats.
- Leveraged LLMs to extract and categorize product attributes from user-generated content, ensuring accurate mapping to Vinted's taxonomy.
- Implemented seamless error handling and validation to maintain listing quality across platforms.
- Reduced manual effort in cross-platform listing management while maintaining high accuracy in product categorization.
Technologies: Ruby on Rails (RoR), REST APIs, PostgreSQL, Amazon Web Services (AWS), DevOps, Orchestration, Large Language Models (LLMs), User Experience (UX), User Interface (UI), Front-end
Technical Consultant
2024 - 2025
Eleos Health
- Inherited a Mongo database containing data on prospective clients and restructured it to fit the needs of sales operations.
- Advised the client on data management strategy for the next six months, advocating for lean approaches and quick results that add value to their sales operations.
- Helped integrate HubSpot and Salesforce with the Mongo database.
Technologies: Python, Node.js, JavaScript, HubSpot, Salesforce, Salesforce Sales Cloud, HubSpot CRM, MongoDB, MongoDB Atlas, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), GitHub, API Design, Observability Tools, User Experience (UX), User Interface (UI)
Technical Consultant
2022 - 2025
Badi
- Assisted the client in maintaining and scaling down an application built on Ruby on Rails.
- Helped cut costs by reviewing the infrastructure, identifying redundancies, and eliminating them where possible.
- Laid out the maintenance strategy for the legacy back-end software to ensure long-term stability.
- Identified and recruited qualified engineers with the necessary experience and qualifications.
- Prioritized bug fixes to ensure optimal performance and user experience.
Technologies: Amazon RDS, AWS ELB, Amazon S3 (AWS S3), AWS Lambda, Amazon API Gateway, Elasticsearch, Ruby on Rails (RoR), Node.js, React, Amazon Web Services (AWS), Amazon EC2, Amazon CloudWatch, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), Sidekiq, Redis, Technical Architecture, RSpec, Full-stack Development, Back-end, Front-end, Payment Gateways, Payment Processing, Card Payments, Docker, API Integration, Express.js, Git, Scalability, Performance, Amazon EKS, Webhooks, Stripe Payments, Design Principles, CI/CD Pipelines, Microservices, APIs, Stripe API, Stripe, Web Development, HTML5, Architecture, Software Design, Technical Leadership, Kubernetes, Real Estate, Optimization, Business Requirements, Technical Requirements, Requirements Analysis, Software Architecture, Databases, Ruby on Rails 7, HTML Email, Email Marketing, DevOps, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), Auth0, Amazon Cognito, GitHub, API Design, Microservices Architecture, Observability Tools, User Experience (UX), User Interface (UI), Performance Optimization
Ruby on Rails Developer
2024 - 2024
Limma, LLC
- Architected and implemented a Rails 7 back-end system from scratch.
- Integrated third-party applications (Google Workspace, GitHub, and Slack) using OAuth authentication, enabling seamless data synchronization across platforms.
- Led feature prioritization and refinement efforts to develop a focused MVP that balanced essential functionality with efficient delivery.
Technologies: Ruby on Rails (RoR), ActiveRecord, Docker, ClickHouse, PostgreSQL, Tailwind CSS, Multi-factor Authentication (MFA), GitHub, API Design, Observability Tools, User Experience (UX), User Interface (UI), Front-end
Full-stack Developer
2023 - 2023
WebStreet, LLC
- Helped maintain the platform during the handover from one team to an external agency.
- Developed multiple features on a standalone Ruby on Rails application and advised the client on product and technical strategies.
- Helped select the agency taking over the project, participating in multiple interviews with candidates and aiding with the final decision.
Technologies: JavaScript, Ruby on Rails (RoR), jQuery, HTML, CSS, Bitbucket, PostgreSQL, Heroku, RSpec, ActiveAdmin, Git, Full-stack, Scalability, Performance, Sidekiq, Webhooks, Design Principles, CI/CD Pipelines, APIs, Web Development, HTML5, Architecture, Software Design, Technical Leadership, Business Requirements, Technical Requirements, Requirements Analysis, Software Architecture, Databases, Ruby on Rails 7, Intuit QuickBooks, HubSpot, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), Auth0, GitHub, API Design, Observability Tools, Hotwire, Ruby on Rails 8, Stimulus, Turbo, User Experience (UX), User Interface (UI), Front-end
Senior Go Engineer
2023 - 2023
Invopop S.L.
- Worked in a fast-paced Y Combinator startup company wearing many hats, including programmer, system architect, client liaison, and project manager.
- Designed and implemented Go services that integrate with local tax agencies to submit electronic invoices.
- Worked directly with customers, including a large hotel management system provider, to address local e-invoicing needs, which may be challenging for companies to comply with.
- Contributed to an open-source GOBL project, writing a library extension that converts e-invoices in the GOBL JSON format into local XML formats. One example is FatturaPA, Italy's electronic invoicing format.
Technologies: Go, NATS, CouchDB, Google Cloud Platform (GCP), Microservices Architecture, Event-driven Architecture, GOBL, XML, Back-end, Front-end, Docker, API Integration, Git, Full-stack, Scalability, Performance, Webhooks, Design Principles, CI/CD Pipelines, Microservices, APIs, Web Development, HTML5, Architecture, Software Design, Kubernetes, Business Requirements, Technical Requirements, Requirements Analysis, Software Architecture, Databases, DigitalOcean, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), Auth0, GitHub, API Design, Observability Tools, User Experience (UX), User Interface (UI)
Back-end Developer
2022 - 2023
Popular Pays Inc
- Improved the slow Ruby on Rails API endpoints by optimizing the database, refactoring the code, consolidating redundant requests, and reducing the response time by up to 60%.
- Added new features to the application by working as a full-stack developer.
- Worked with a team spread across the world in various time zones, making appropriate use of synchronous and asynchronous communication channels.
Technologies: JavaScript, Ruby on Rails (RoR), Node.js, Ember.js, TypeScript, PostgreSQL, Technical Architecture, React, Heroku, RSpec, ActiveAdmin, Back-end, Front-end, Payment Gateways, Payment Processing, API Integration, Git, Scalability, Performance, Sidekiq, Webhooks, Stripe Payments, Design Principles, CI/CD Pipelines, APIs, Stripe API, Stripe, Web Development, HTML5, Architecture, Software Design, Optimization, Business Requirements, Technical Requirements, Requirements Analysis, Social Media Apps, Software Architecture, Databases, Ruby on Rails 7, Facebook API, Instagram API, HubSpot, HTML Email, Email Marketing, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), Auth0, GitHub, API Design, Observability Tools, User Experience (UX), User Interface (UI), Performance Optimization
Senior Back-end Engineer
2021 - 2021
Cleo
- Developed a robust Ruby on Rails API for handling subscription payments for a platform with 3 million users.
- Introduced a more comprehensive framework for testing features before deployment to production.
- Implemented the initiatives to improve software engineering principles and team processes to meet growing business needs.
Technologies: Ruby, Ruby on Rails (RoR), JavaScript, React Native, Heroku, User Interviews, SQL, Software Architecture, HTML, CSS, Amazon Web Services (AWS), Back-end Development, JSON Web Tokens (JWT), Back-end, APIs, TypeScript, MySQL, Technical Architecture, React, RSpec, jQuery, Payment Gateways, Payment Processing, Card Payments, API Integration, Git, Scalability, Performance, Sidekiq, Webhooks, Stripe Payments, Design Principles, CI/CD Pipelines, Stripe API, Stripe, Web Development, Asana, HTML5, Architecture, Software Design, Optimization, Business Requirements, Technical Requirements, Requirements Analysis, Databases, HTML Email, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), GitHub, API Design, Observability Tools, Bootstrap, User Experience (UX), User Interface (UI)
Back-end Engineer
2019 - 2021
Badi
- Worked on a room-rental platform with over 3 million users in a fast-paced startup environment built on Ruby on Rails.
- Led the effort to design and fully implement a recurring payments system integrated with Stripe.
- Proposed, designed, and implemented an event-driven messaging system for processing data streams using AWS SMS and Amazon SQS upon performing a cost-benefit analysis of different tools at disposal.
- Rewrote the legacy integration with third-party platforms into a scalable serverless AWS Lambda system.
- Oversaw the effort to remove internal bottlenecks by improving the integration between tools used by sales, marketing, customer experience, and finance departments.
- Designed and implemented an invoicing system for the application. The code generated sequential invoices sent to both the users and the tax authority through an integration with our accounting partner's system.
- Participated in the recruitment process as a technical screener.
- Collaborated closely with the performance marketing team as a growth engineer, building and overseeing the necessary technology for experiments to improve specific metrics like CTR and conversion rate.
Technologies: Ruby, JavaScript, HTML, CSS, Node.js, Ruby on Rails (RoR), Amazon EC2, Amazon RDS, Redis, AWS Lambda, AWS CloudFormation, Amazon Simple Queue Service (SQS), Amazon S3 (AWS S3), Stripe, Recurring Payments, GrapesJS, Sentry, Amazon CloudWatch, Continuous Delivery (CD), New Relic, Serverless, Interviewing, Amazon Simple Notification Service (SNS), SQL, Software Architecture, SCSS, Amazon Web Services (AWS), Back-end Development, OAuth, JSON Web Tokens (JWT), Back-end, APIs, Engineering, Growth, AWS Server Migration Service (SMS), TypeScript, Firebase, MySQL, PostgreSQL, Technical Architecture, React, RSpec, ActiveAdmin, Microsoft Dynamics, Full-stack Development, Front-end, Payment Gateways, Payment Processing, Card Payments, Docker, API Integration, Express.js, Git, Full-stack, Scalability, Performance, Amazon EKS, Sidekiq, Webhooks, Stripe Payments, Design Principles, CI/CD Pipelines, Microservices, Stripe API, Web Development, HTML5, Architecture, Software Design, Kubernetes, Real Estate, Optimization, Business Requirements, Technical Requirements, Requirements Analysis, Databases, HTML Email, Email Marketing, DevOps, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), Amazon Cognito, GitHub, API Design, Microservices Architecture, Observability Tools, Bootstrap, User Experience (UX), User Interface (UI)
Consultant | Software Developer
2018 - 2019
ThoughtWorks
- Worked with various clients in different industries as both a software developer and a consultant trained in Agile methodologies.
- Acted as a Swift developer building an iOS app for a marketplace company with over 30 million monthly users.
- Built and maintained a scalable back-end for the above app with Scala and Clojure deployed on AWS Lambda.
- Worked closely with clients, helping not only with technical solutions but also by refining their business aims and translating broad objectives into actionable goals.
- Owned the entire lifecycle of software we wrote in the team, from planning and execution to building and maintaining the deployment infrastructure.
- Acted as a back-end Java and Scala developer for a client in the real estate industry with over 10 million monthly users.
- Developed applications in an environment where maintainability, security, and reliability were of utmost importance.
- Initiated and led a meetup centered around hardware experimentation with funding from the company.
- Took an active part in company councils and working groups like the environmental council, ThoughtWorks Arts initiatives, and recruiting process improvements.
- Interviewed candidates as a cultural fit screener.
Technologies: Scala, Swift, Java, JavaScript, Clojure, Ruby, Amazon S3 (AWS S3), Amazon EC2, Amazon API Gateway, AWS Lambda, Amazon Kinesis, Selenium, Jenkins, CircleCI, Continuous Delivery (CD), Pair Programming, Test-driven Development (TDD), Agile, Kanban, Scrum, Scrumban, IT Consulting, Quality Assurance (QA), Objectives & Key Results (OKRs), Event-driven Architecture, OWASP, Web Security, iOS, SQL, HTML, CSS, Amazon Web Services (AWS), Back-end Development, Node.js, Back-end, APIs, NoSQL, TypeScript, MySQL, PostgreSQL, MongoDB, Technical Architecture, RSpec, jQuery, Bitbucket, Go, Full-stack Development, Front-end, Payment Gateways, Payment Processing, Docker, API Integration, Express.js, Git, Full-stack, Scalability, Performance, Amazon EKS, Webhooks, Stripe Payments, Design Principles, CI/CD Pipelines, Microservices, Stripe API, Web Development, Architecture, Software Design, Business Requirements, Technical Requirements, Requirements Analysis, Databases, DevOps, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), Auth0, GitHub, API Design, Microservices Architecture, Observability Tools, User Experience (UX), User Interface (UI)
Ruby Developer
2017 - 2018
Workshare (acquired by Litera)
- Worked on an application that helped major law firms securely manage documents and perform legal transactions through a web platform.
- Rewrote legacy Java applications into more maintainable Ruby services.
- Worked with a back-end system comprising of a Rails monolith and numerous microservices communicating with each other via event streams and HTTP.
Technologies: Ruby, Ruby on Rails (RoR), Java, JavaScript, Kafka Streams, Jenkins, Amazon EC2, Amazon S3 (AWS S3), Event-driven Architecture, Microservices Architecture, Kanban, Test-driven Development (TDD), Capybara, SQL, HTML, CSS, SCSS, Amazon Web Services (AWS), Back-end Development, OAuth, Node.js, Back-end, APIs, NoSQL, MySQL, PostgreSQL, RSpec, jQuery, Docker, API Integration, Express.js, Git, Performance, Sidekiq, Webhooks, Design Principles, CI/CD Pipelines, Microservices, Web Development, HTML5, Software Design, Business Requirements, Technical Requirements, Requirements Analysis, Databases, REST APIs, API Development, OAuth 2, Multi-factor Authentication (MFA), GitHub, API Design, Observability Tools, Bootstrap, User Experience (UX), User Interface (UI)
Experience
Recurring Payments System Serving a Million Users
At Badi, I spearheaded the initiative to design and build a recurring payment system for users subscribed to premium plans. The system was integrated with Stripe Billing. The project's scope included full integration with existing back-end systems and internal tools used by finance and sales. I led a team of three engineers to complete this task, overseeing the project's entire lifecycle.
Designing an Event-driven Messaging System
At Badi, we struggled to maintain a complex integration between our back-end systems, over a dozen external partner platforms, and tools used internally like Salesforce and Zendesk. These intra-service communications were performed through conventional synchronous HTTP calls.
As a result, a decision was made to introduce an event-driven system, and I was tasked with researching, proposing, designing, and implementing a solution. I performed a cost-benefit analysis of different available tools. In addition, I chose a combination of AWS Simple Queue Service (SQS) and AWS Simple Notification System (SNS) based on the projected growth of the company, available budget, team capabilities, and current data load. With the help of two other engineers, I then developed an event bus that is still in use by the platform today.
As a result, a decision was made to introduce an event-driven system, and I was tasked with researching, proposing, designing, and implementing a solution. I performed a cost-benefit analysis of different available tools. In addition, I chose a combination of AWS Simple Queue Service (SQS) and AWS Simple Notification System (SNS) based on the projected growth of the company, available budget, team capabilities, and current data load. With the help of two other engineers, I then developed an event bus that is still in use by the platform today.
Optimizing the Performance of a Back-end API
Many of the client's website pages took a painfully long time to load and negatively impacted the users' workflow. I was tasked with optimizing the Ruby on Rails API. I implemented the following: database query optimizations, database index optimizations, code refactors, and consolidations of API requests from front-end applications, and introduced a more efficient data serialization library.
As a result, we were able to decrease the response time by more than half and achieve a significant reduction in memory allocation.
As a result, we were able to decrease the response time by more than half and achieve a significant reduction in memory allocation.
Open Source Contribution for Business Language Standardization
https://gobl.org/In my collaboration with Invopop, I played a crucial role in enhancing GOBL, a JSON-based document format designed to precisely represent business records like invoices and purchase orders across diverse international tax regimes. More than just a format, GOBL encompasses a toolkit, including a Go language library, which aids in calculating totals and taxes and ensures document compliance with local tax laws. This technology underpins Invopop's global invoicing platform. I led the initiative to adapt GOBL to the Italian tax system, which required a deep understanding of Italy's intricate invoicing regulations and their integration into GOBL.
Skills
Libraries/APIs
Node.js, Stripe, Sidekiq, Stripe API, REST APIs, API Development, jQuery, Facebook API, Instagram API, React, ActiveRecord
Tools
RSpec, Git, Auth0, Amazon Cognito, GitHub, Turbo, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), Bitbucket, Microsoft Dynamics, Observability Tools, Hotwire, Kafka Streams, Jenkins, CircleCI, AWS CloudFormation, Sentry, Amazon CloudWatch, Cron, AWS ELB, Amazon EKS, Asana, Salesforce Sales Cloud, MongoDB Atlas
Languages
Ruby, JavaScript, Go, SQL, HTML, CSS, TypeScript, HTML5, Java, Scala, Swift, Clojure, SCSS, XML, Python
Frameworks
Ruby on Rails (RoR), Ruby on Rails 7, OAuth 2, Stimulus, Express.js, Bootstrap, Capybara, Selenium, GrapesJS, React Native, JSON Web Tokens (JWT), Ember.js, Tailwind CSS
Paradigms
Microservices Architecture, Microservices, Requirements Analysis, Scrum, Test-driven Development (TDD), Agile, Refactoring, Event-driven Architecture, Kanban, Continuous Delivery (CD), Pair Programming, Objectives & Key Results (OKRs), DevOps
Platforms
HubSpot, AWS Lambda, Heroku, Amazon Web Services (AWS), Docker, DigitalOcean, Amazon EC2, iOS, New Relic, Firebase, Google Cloud Platform (GCP), Kubernetes, Salesforce
Storage
MySQL, PostgreSQL, Databases, RDBMS, NoSQL, Amazon S3 (AWS S3), Redis, MongoDB, Elasticsearch, CouchDB, JSON, ClickHouse
Other
Software Architecture, Back-end, APIs, Technical Architecture, ActiveAdmin, Payment Gateways, Payment Processing, API Integration, Full-stack, Scalability, Performance, Optimization, Webhooks, Stripe Payments, Design Principles, Web Development, Software Design, Business Requirements, Technical Requirements, HTML Email, Email Marketing, Multi-factor Authentication (MFA), API Design, Ruby on Rails 8, User Experience (UX), Performance Optimization, Web Security, Back-end Development, Full-stack Development, Front-end, Card Payments, CI/CD Pipelines, Architecture, Technical Leadership, Real Estate, Social Media Apps, Intuit QuickBooks, User Interface (UI), Amazon API Gateway, Amazon Kinesis, Scrumban, IT Consulting, Quality Assurance (QA), OWASP, Amazon RDS, AWS Server Migration Service (SMS), Recurring Payments, Serverless, Interviewing, User Interviews, OAuth, Engineering, Growth, NATS, GOBL, HubSpot CRM, Orchestration, Large Language Models (LLMs)
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