profile

Samuel Espinoza

Software Developer


Passionate and highly skilled Software Engineer with over 9 years of IT industry experience, specializing in building scalable applications. I have a strong Backend foundation and I can take DevOps tasks to automate and improve processes. I also have experience with Frontend technologies.

Contributed to projects both in Development and Tech leadership roles such as Tech Lead, Scrum Master.

My passion is in designing APIs and architecting microservices, with a deep understanding of Docker and CI/CD pipelines for deployment. My expertise includes the full software development lifecycle, from requirements gathering and software architecture to prototyping, testing, and deployment. I thrive in agile environments.


Experience

Senior Software Engineer — Cognizant

June 2025 – Present · 6 months · Vilnius, Lithuania

  • Worked in a Cognizant team for a financial compliance client focused on SEC filings.
  • Improved the codebase using TypeScript and Git Flow best practices.
  • Enhanced project structure by preparing migration to an Nx Monorepo.
  • Actively worked with GitHub CI/CD and Harness pipelines across multiple environments.
  • Gained experience in a large project with 200+ professionals across time zones, including 90 from Cognizant.
  • Performed Java project setup for local development environments.
  • Improved test quality and coverage using Jest for unit and integration tests.
  • Participated in exploratory testing sessions to enhance product quality.
  • Evaluated candidates through technical interviews for new projects.

Technical Lead — Cognizant

March 2025 – June 2025 · 4 months · Kaunas, Lithuania

  • Worked closely with a client on their MRO (supplies & industrial products) project.
  • Led a distributed team of 11 members across multiple time zones with Scrum practices.
  • Successfully offboarded the client and onboarded a new team with structured knowledge transfer.
  • Collaborated on task estimation, story points, and sprint capacity planning.
  • Developed backend features using TypeScript, Node.js microservices, and AWS.
  • Led deployment procedures and improved documentation for internal processes.
  • Performed monitoring activities using DataDog.
  • Acted as a communication bridge between the client, my team, and incoming team members.

Senior Full Stack Engineer — Togal.AI

October 2024 – January 2025 · 4 months · Lithuania

  • Collaborated remotely with an interdisciplinary agile team across time zones.
  • Enhanced PDF generation workflows using D3.js.
  • Designed and implemented test cases from scratch to improve code reliability.
  • Used Swagger for documentation and API structure communication.
  • Authored technical documentation to improve team productivity.

Software Engineer — Games Global

November 2021 – July 2024 · 2 years 9 months · Tallinn, Estonia

  • Designed a PUB/SUB event-driven architecture with Node.js microservices, improving video encoding speed by 43% via horizontal scaling.
  • Implemented solutions using Docker, RabbitMQ, TypeScript, PostgreSQL, Redis, and TDD with Mocha/Chai.
  • Speaker at Brown Bag Conference — “Horizontal Scaling with Publish/Subscriber Systems”.
  • Redesigned internal tools in React.js with Ant Design and Redux.
  • Built CI/CD integrations in GitLab for linting, testing, and deployment.
  • Managed static assets via AWS S3 and Akamai pipeline.
  • Created API documentation with Swagger.
  • Contributed to games including “Flipping Fortunes” (Vue + Godot) and “BlackJack RPG”.
  • Developed CLI tools to streamline CI/CD processes.
  • Wrote extensive documentation in Confluence.

Full Stack Engineer — Jooycar

April 2021 – October 2021 · 7 months · Santiago, Chile

  • Maintained Node.js microservices using Express, Ramda, and asynchronous RESTful patterns.
  • Used Docker, AWS S3, and Lambda for deployments.
  • Practiced TDD with Mocha, Chai, and Sinon.
  • Created API documentation with Swagger.
  • Built integrations with external SOAP and REST APIs.

Software Engineer — ZeroQ

September 2017 – March 2021 · 3 years 7 months · Santiago, Chile

  • Maintained the core real-time service built with Node.js, Express, Redux, Socket.IO, Ramda, and Axios.
  • Enhanced Rails API project for the statistical panel.
  • Maintained microservices in Node.js, Crystal, and Ruby.
  • Co-designed “zq”, a Crystal CLI tool for technical support automation.
  • Optimized Docker images using Alpine, reducing image size by 60%.
  • Migrated Docker registries and images to new server infrastructure.
  • Implemented automation scripts to boost operational efficiency.
  • Built SOAP/REST integrations for external services.
  • Created extensive documentation for internal and external use.

Software Developer — UTFSM (Infrastructure & Technology Unit)

January 2015 – March 2015 · 3 months · Valparaíso, Chile

  • Participated in the upgrade of the IT department’s intranet using Ruby Gems.

Education

Ingeniería en Ejecución Informática (Software Engineering)

Universidad Técnica Federico Santa María - Chile

Milestones

  • Designer of PESS (Post-Emergency Support System) – 2014
  • Presenter at the XXII Software Fair (2014)

Volunteering

Volunteer — Universidad Técnica Federico Santa María

April 2014 · 1 month · Valparaíso, Chile

  • Participated in debris removal efforts after the massive fire that struck the hills of Valparaíso, contributing to the restoration and safety of affected areas.

Co-founder of Digital Literacy Course — Presbiterian Church

April 2014 – April 2016 · 2 years 1 month · Viña del Mar, Chile

  • Co-founder and main instructor of a digital literacy program aimed at senior citizens in Viña del Mar.
  • Taught essential computer skills enabling attendees to improve their daily activities, communication, and overall quality of life.
  • Program was highly appreciated and adopted by multiple local groups.

Skills

Languages

JavaScript

JavaScript

TypeScript

TypeScript

Bash

Bash

Ruby

Ruby

Rust (learning)

Rust (learning)

Markup & Styling

HTML

HTML

CSS

CSS

Material UI

Material UI

Ant Design

Ant Design

Styled Components

Styled Components

Tailwind

Tailwind

Frameworks, Libraries & Others

Node.js

Node.js

Express

Express

Nest.js

Nest.js

React

React

Next.js

Next.js

Redux

Redux

Axios

Axios

Moment.js

Moment.js

Socket.IO

Socket.IO

Ramda

Ramda

Rails

Rails

Databases

PostgreSQL

PostgreSQL

MySQL

MySQL

SQLite

SQLite

Microsoft SQL Server

Microsoft SQL Server

MongoDB

MongoDB

Redis

Redis

Testing & Development

Jest

Jest

Mocha

Mocha

Chai

Chai

Cypress

Cypress

Nodemon

Nodemon

Sinon

Sinon

ESLint

ESLint

Prettier

Prettier

DevOps & Computer Software

AWS

AWS

Azure

Azure

Linux

Linux

MacOS

MacOS

Git

Git

Docker

Docker

Kubernetes (learning)

Kubernetes (learning)

GitLab

GitLab

GitHub

GitHub

BitBucket

BitBucket

New Relic

New Relic

Datadog

Datadog

Sentry

Sentry

Harness

Harness

Practices & Paradigms

Object Oriented Programming

Object Oriented Programming

Functional Programming

Functional Programming

Event‑driven architecture

Event‑driven architecture

Agile

Agile

Scrum

Scrum

Test Driven Development (TDD)

Test Driven Development (TDD)

CI/CD

CI/CD

Hobbies

Reading science fiction novels, playing boardgames and working in side projects. I like photography as well, macros.

If you're a fan of Dune, The Lord of the Rings, Starwars or Harry Potter we're going to be friends.

References

Daniel Salazar — disalazarg@gmail.com— ZeroQ Ex-CTO

Ernesto Erdmann — eerdmann@zeroq.cl— ZeroQ CEO

Recommendations

These are real testimonials from people I've worked with. You can read all of them on my LinkedIn profile.

What my managers say about me

Samuel is a very proficient full stack developer with broad range of skills, both on the frontend and backend. He is always very much into details of each technical solution and knows how to tackle the problems. It is always very easy when discussing any tasks or projects with him as we always reach the best solution together. I think Sam is a good fit in any development team, while driving the system architecture overall or when delivering good end-user applications. Overall a great pleasure to be able to work with Sam.

Tiit Maripuu — Game Producer, Games Global

After two years of working on a internal tools portal project, I'm happy to see how a legacy SW has became a modular scalable product that studio processes heavily depend on. Samuel has exposed his skills in frontend dev (React), dockerized microservices (TypeScript), message queues and SQL DB. His passion to excellence has created UX, that people like to work with. Proposed solutions have been thought through and great balance of effort and gain.

Indrek Juhani — Technical Director/SDM, Games Global

Samuel is one of the most reliable and trustworthy professionals I've had the privilege of working with, constantly striving to improve his skills and the quality of his work, as well as communicating about any potential improvement or roadblock in projects he's involved with in an opportune and effective manner.Samuel is one of the most reliable and trustworthy professionals I've had the privilege of working with, constantly striving to improve his skills and the quality of his work, as well as communicating about any potential improvement or roadblock in projects he's involved with in an opportune and effective manner.

Daniel Salazar — ex-CTO ZeroQ and Senior Software Developer at Jooycar)

I am lucky to belong to the same team as Samuel, he is an excellent professional, capable, with solid knowledge in several languages and technologies. With a constant thirst to learn and overcome. He dares to accept computer challenges and manages to solve them effectively. On a personal level, a very good friend, I can also say that he is a person with values, principles, full of optimism and good spirits.

Hervis Pichardo — CTO, ZeroQ

What my colleagues say about me

Samuel quickly stepped up to lead a large, legacy project and handled it with confidence. He kept communication with clients smooth, led agile processes effectively, and even made critical code updates. He asked the right questions and knew when to bring in support to keep things moving. Overall, it was a really enjoyable experience working with him.

Haroldas Bartusevičius — Software Engineer at Cognizant.

It was a pleasure for me to work with Samuel, a talented, experienced, and passionate software development engineer. He has great interpersonal and communication skills, great team player, and is a friendly and sincere individual. He has great technical and problem-solving skills. He is a fast learner and always open to new challenges. I believe he can be a great asset to any organization that he joins.

Damir Mustafaev — Senior Software Engineer (Games Global)

Samuel is a very passionate developer, supportive and kind colleague, proactive professional with a wide range of interests. He has been creating multiple useful tools that are helping both QAs and other developers, successfully implementing both frontend and backend parts. Sam is also eager to learn something new and always has in mind a couple of good pet project ideas to implement or technologies to check, coffee conversations about those are always inspiring

Denis Golov — Software Developer (Games Global)

Sam is a truly professional developer. I rarely see that spark in the eyes of Dev, when he encounters new obstacles and tries to find the best solution to overcome them. I'm very glad to work with him, as he's very responsive and helped me and the QA team a lot, by developing/redesigning tools which were designed to fully fulfill our requests. He is always ready to help with any issues and a great interlocutor on various topics. It was a pleasure to be a part of projects where he was involved.

Vadim Pilipenko — QA Specialist L2 (Games Global)

I worked for 3 years with Samuel in the development area of ZeroQ, demonstrating incredible problem-solving skills and a relentless pursuit of knowledge. He consistently improves solutions within the projects he is involved in. I highly recommend Samuel for any job as he is an excellent professional who pays close attention to technical details.

Kenier Becerra — QA Engineer and technical operations (ZeroQ)

Samuel is a talented Fullstack Developer. His passion for learning and his ability to acquire new skills are impressive. From React to Ruby, he is always expanding his toolkit. A true technology enthusiast! Working with him was a delight; he always seeks the best and most efficient solution. If you need a developer who can find the perfect solution, don’t hesitate to get in touch with Sam.

Rafael Romero — Frontend Developer (ZeroQ)

Working with Samuel has been amazing. His work ethic, productivity and abilities as impressive to day the least. He has always been extremely easily to work with and very helpfull even with ad-hoc requirements and assistance.

Jason Cross — Game Developer (Games Global)

Samuel is a skilled and dedicated professional who creates solid solutions. On top of that, he is always willing to help/guide others and eager to learn from others too

Ranko Bakker — Engineering Lead (Luminor)

Sam is a developer concerned with delivering quality solutions, focused on teamwork and good practices. In the projects that we work together, we had a synergy to achieve the objectives that were proposed to us. I think Sam is a great contribution to any company

Nicolás Góngora — Senior Frontend Developer (Jooycar)

I had the opportunity to work with Sam at Jooycar on many projects, we did many things, from pair programming to having talks about technologies and seeing what we could improve or new things to implement. He is a great colleague, professional, orderly, concerned with delivering good results. It would be a pleasure to work with him again.

César Morales — Software Developer (Jooycar)

Sam is one of those developers who have great determination and dedication, getting jobs done and continuing to learn. As a partner, a great person, someone with who you share different topics and share a coffee in the middle of conversations. Sam is an invaluable person who will give quality in development and as a partner wherever he goes.

Jorge Avilés — Backend Developer (ZeroQ)

Samuel is an excellent professional, higly committed to the work and always worried about giving his best. He's always trying to cooperate to the team dynamic, giving his best ideas to support the group growth. He's very eager to learn, knows when to take decissions and how to be a good leader in order to inspire his team mates and to help other departments to reach their goals. Samuel also knows how to contribute with knowledge and techniques to the company evolution, always trying to improve our work. methodology. He has shown an amazing evolution to become a full stack developer, working and learning on his own and taking the best advantage of all the knowledge he has got over the past two years.

Kristina Padrino — Customer Success Manager (ZeroQ)

Samuel is a professional 100% committed to his work, proactive and able to understand the needs of companies. I highlight from Sam the great capacity to generate interpersonal relationships, adding rigour in his work, his commitment, disposition and his constant search for knowledge. It has been a pleasure working with him

Sebastian Luna — Product Manager (Security Group Banking)

Samuel is a great professional. His high commitment and work ethic made him an invaluable collaborator. I have seen how year after year all his technical skill has been improved thank to his passion for the work and continuos study of his discipline.

Ernesto Erdmann — CEO ZeroQ

The importance in supporting our team management is fundamental, it is a pleasure to have Samuel and his collaboration from the development area, I highlight the ingenuity in the face of problem solving, he surprised us with his cooking skills with the excellent bread that brought us to the office.

Patricio Gatica — Cybersecurity Engineer (ZeroQ)

I had the good lucky of working with Samuel. I think that's very strange to find people enough smart, kind and methodical as Samuel. Working with he showed me that you can be a great person and a good developer. His disposition to always solve problems giving solutions that are robust is a very clear characteristic of Samuel. I know that any project that works with Samuel will get a very good developer and will do a hiring of high level because get a worker that is trustworthy and that have all the capability to solve any task is not something that happen all days.

Lucas Parra — Software Architect (ZeroQ) note: LinkedIn account deleted.

Sam is an excellent co-worker, kind, responsible, cares about helping colleagues and works very well as a team. In addition as a programmer, he has experience in technologies widely used today such as javascript and docker. He likes to learn and research new technologies

César Vallenilla — Software Developer (ZeroQ)