Miguel Prieto, Developer in Asuncion, Paraguay
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Miguel Prieto

Verified Expert  in Engineering

Full-stack Developer

Asuncion, Paraguay
Toptal Member Since
April 27, 2016

Miguel describes his job as turning ideas and requirements into production-ready, maintainable, and scalable code that runs within a well-engineered environment. He has collaborated on different projects with many technologies in his years of experience as a developer, architect, and consultant. Regardless of the task at hand or the technology, Miguel embraces software development challenges with professionalism and enthusiasm.


Java, Spring Boot, Microservices, Redis, REST APIs, Amazon Web Services (AWS)...
Latch (via Toptal)
Java, Gradle, gRPC, Play Framework, Spring Boot, REST...
Synthesis AI (via Toptal)
TypeScript, React, REST, Docker, YARN, CircleCI, Amazon Web Services (AWS)...




Preferred Environment

Git, Visual Studio Code (VS Code), IntelliJ IDEA, Zsh, Bash, Java, Kotlin, Groovy, Docker, Kubernetes

The most amazing...

...project I've built with other Toptalers was a video streaming platform using WebRTC and RTMP and a post-processing pipeline with AWS Lambda and MediaConvert.

Work Experience

Senior Software Engineer

2021 - 2022
  • Built an authentication and authorization framework for a microservices orchestration platform (Orkes Conductor) based on the popular open source platform Conductor created by Netflix.
  • Integrated Auth0, Okta, Firebase, and Generic OIDC providers as authentication providers into Orkes Conductor.
  • Oversaw the release of Orkes Conductor Playground—a free environment for developers to try out and explore more about Conductor.
  • Worked on designing and implementing several key enterprise features such as tagging Metadata, security and performance enhancement of HTTP task, Webhook support, GraalJS integration, and Metadata Migration.
  • Assumed the role of a technical project manager during a successful SOC2 Type 2 audit. Adjusted the software development lifecycle to achieve compliance.
  • Implemented infrastructure security measures and monitoring to achieve SOC2 Type 2 compliance.
  • Contributed to Netflix Conductor and other open source projects related to it.
Technologies: Java, Spring Boot, Microservices, Redis, REST APIs, Amazon Web Services (AWS), Azure, Orchestration, PostgreSQL, gRPC, Role-based Access Control (RBAC), Single Sign-on (SSO), Auth0, Okta, Firebase, OpenID Connect (OIDC), Netflix, Kubernetes, Groovy, JavaScript, HTML, CSS

Lead Back-end Engineer

2021 - 2021
Latch (via Toptal)
  • Designed and documented the back-end architecture of new services that enabled Latch to open a new vertical in commercial buildings.
  • Supported the PM in the development and estimation of user stories that gave visibility to the project.
  • Defined the technical approach and enforced best practices within the team.
  • Bootstrapped the projects of the new back-end components.
  • Designed and implemented a REST API for client/back-end communication and gRPC API for sync inter-process communication.
  • Established conventions and guidelines on how to write Kafka consumers using Spring Boot and Spring Kafka.
  • Released a Commercial MVP on time in one of Manhattan’s most iconic buildings.
Technologies: Java, Gradle, gRPC, Play Framework, Spring Boot, REST, Amazon Web Services (AWS), Liquibase, PostgreSQL, MongoDB, Docker, Terraform, Terragrunt, Ansible, Apache Kafka, Jira, HTML

Front-end Engineer

2021 - 2021
Synthesis AI (via Toptal)
  • Built a React application for user onboarding and user and job visualization and management.
  • Designed a REST API in collaboration with the back-end development team.
  • Integrated with Stripe for saving payment methods and collecting payments.
  • Cooperated in establishing a development process to properly track the project's progress using Github's project planning for developer tools.
  • Set up the deployment of the React application to AWS using CircleCI.
  • Released an MVP meeting an aggressive deadline without sacrificing quality.
Technologies: TypeScript, React, REST, Docker, YARN, CircleCI, Amazon Web Services (AWS), JavaScript, HTML, CSS

Full-stack Engineer

2020 - 2021
Kekal (via Toptal)
  • Wrote a WebRTC live stream component using React Functional Components, Redux, and TypeScript to allow educators to stream classes from the browser.
  • Built the back end as Spring Boot microservices, written in Kotlin and deployed as dockerized containers on AWS Fargate.
  • Created a video processing pipeline using AWS Lambda functions, written in JavaScript employing AWS MediaConvert, SQS, and S3.
  • Set up a production-ready self-hosted Wowza Streaming Engine in EC2.
  • Wrote a Wowza Streaming Engine module in Java for authentication and to persist and retrieve video metadata.
  • Automated the deployment of the WSE module using Ansible.
  • Built an integration with an Indian payment gateway, RazorPay.
Technologies: React, Spring Boot, Kotlin, Amazon Web Services (AWS), TypeScript, AWS Lambda, Amazon Elastic Container Service (Amazon ECS), Amazon Elastic Container Registry (ECR), Amazon S3 (AWS S3), Amazon Simple Queue Service (SQS), JavaScript, HTML, CSS

Full-stack Engineer

2020 - 2020
Colorado General Assembly (via Toptal)
  • Developed the UI of a custom document management system based on existing mockups using ES6, React, and Redux.
  • Wrote tests for React Components using Jest and Enzyme.
  • Built a RESTful API to retrieve, store, and search documents using Java and Spring Boot.
  • Wrote unit and integration tests for services and controllers using JUnit 5, AssertJ, Mockito, and other libraries and utilities provided by spring-boot-starter-test.
  • Set up a CI/CD pipeline using Bitbucket Pipelines for both front and back ends.
  • Created a CLI tool to translate documents in a legacy markup language to XML using ANTLR.
Technologies: ANTLR, MySQL, JUnit, Spring Boot, Java, Jest, ECMAScript (ES6), Redux, React, HTML, CSS

Senior Software Engineer

2016 - 2019
Rooam (via Toptal)
  • Designed and implemented RESTful APIs for features such as user authentication using Facebook, phone verification, and paying and closing a tab at a bar or restaurant.
  • Built Spring Boot applications for the features mentioned above following a message passing microservices architecture using Groovy, MongoDB and RabbitMQ.
  • Created Ansible playbooks for provisioning and deployment of services in cloud providers such as DigitalOcean and Linode.
  • Created Jenkins jobs for automation of jobs such as building the back-end applications and mobile apps.
  • Led the development of the Android application and also supported it with bug fixes.
  • Implemented a web application using React for ticket management at large events such as festivals and restaurants.
  • Integrated Rooam's back end with external services like Twilio, Mailgun, Mailchimp, Stripe, Braintree, and others.
Technologies: React, iOS, Android, Java, Groovy, MongoDB, RabbitMQ, Spring Boot, JavaScript, Jira, HTML, CSS

Java Architect

2015 - 2016
Aurea Software
  • Developed a web application that acts as a wizard to onboard new customers to an existing enterprise mail failover system using mainly jQuery, Spring Boot, and PostgreSQL.
  • Developed a Java library (used by other developers at the company) that communicates with a REST API for user and account management.
  • Deployed and maintained a nontrivial back-end infrastructure of 50+ EC2 instances in AWS.
  • Solved infrastructure and deployment issues during migration to AWS.
  • Transferred knowledge and trained new engineers.
Technologies: Amazon Web Services (AWS), Postfix, PostgreSQL, RabbitMQ, Single-page Applications (SPA), REST, Spring Boot, Spring, Java, Jira, HTML

Senior Software Developer

2010 - 2015
Sodep S.A.
  • Developed a web-based document management system with very strict security requirements using Java Enterprise technologies. It's currently used in banks and financial entities.
  • Maintained and developed new features for an indoor navigation system for Netherlands-based company Smartsigns.
  • Developed three mobile apps in Java ME and Windows Mobile (in late 2010) for indoor navigation studies and research.
  • Led and played a key role in the product development for Captura, an application which allows users to capture field data using mobile devices.
  • Developed an Android application and its back end for a major nonprofit organization that helps children with disabilities (Teletón).
  • Redesigned and continued the development of an Android application used in the research of bipolar disorder by the Hospital de Clínic de Barcelona.
  • Developed a Facebook app that allowed users to change their profile and cover picture with an image from Teletón to show their support.
  • Taught Java as a Java EE instructor at Sudameris Bank.
  • Created web automation tests with Selenium WebDriver for regression testing of web applications using Jenkins.
Technologies: Android, Windows Mobile, Java ME, Bootstrap, Backbone.js, RequireJS, jQuery, JavaScript, Spring Data, Spring MVC, Spring, MySQL, PostgreSQL, Apache Tomcat, JDBC, JSF, JPA, JEE, Java, Jira, HTML

Software Developer

2008 - 2010
Nucleo S.A. (Telecom Personal Paraguay)
  • Maintained and developed an enterprise-oriented mobile application based on STK menus to capture field data using STKML, SATML, and Java Card.
  • Developed Windows services that communicated via SMPP with the SMSC to obtain data from the STK applications, validate it, and store it in the database.
  • Created a web application in ASP.NET using C# that allowed users to visualize their data.
  • Developed several mobile applications with Java ME.
  • Created custom web reports for the marketing department using ASP.NET.
Technologies: SMPP, Java Card, Java ME, Java, Microsoft SQL Server, Web Services, ASP.NET, C#, .NET

Freelance Software Developer and Consultant

2006 - 2008
  • Implemented an accounting module of an ERP using PHP with SOAP-based web services on the back end and a GTK#-based client.
  • Created an expense control application using JEE 5.
  • Provided Linux system administration.
  • Consulted on IT matters for small and medium-sized businesses.
  • Developed custom software for cross-checking reports and printing invoices in VB.NET.
Technologies: Linux, Mono, MySQL, .NET, C#, PHP


Teletón is a nonprofit organization that hosts fundraising events a couple times a year that rely on heavy media coverage for their success.

Teletón needed to evolve, to move beyond traditional media (TV and radio) into social media as an organization. So, with Sodep S.A., it started a massive project which included a complete restructure of the communication workflow and the development of software that would allow efficient live storytelling of the events.

The mobile applications (which can be downloaded from the stores) are some of the visible results of the whole project.


Captura is a product that allows users to capture field data through mobile devices.

An admin user designs a form with an easy-to-use drag-and-drop form designer in the web application. Then he/she sets the appropriate permissions and the form is synced to the devices.

Mobile users who receive that form will be able to input data in various formats (simple text, time, date, pictures, location, etc.) according to the form's design.

Input data can then be visualized through several customizable reports on the web application or it can be accessed through a REST API which allows integration with other existing systems or applications.


Through Toptal, I was Rooam's first hire in 2016. As the first full-time engineer at a well-funded but early-stage startup, I took part of the bootstrapping and setup of almost all back-end components (services and infrastructure) and mobile applications.

For someone who loves technology and building applications, Rooam was a great experience because I was one of the main contributors in an awesome and ambitious project which resulted in an app that solves a major pain point at bars and restaurants in the US, paying your tab.
2002 - 2008

Bachelor's Degree in Computer Science

Universidad Católica Nuestra Señora de la Asunción - Asunción, Paraguay


Functional Programming Principles in Scala

École Polytechnique Fédérale de Lausanne | via Coursera


Data Structures

UC San Diego | via Coursera


Algorithmic Toolbox

UC San Diego | via Coursera


Parallel, Concurrent, and Distributed Programming in Java Specialization

Rice University | via Coursera


Building Scalable Java Microservices with Spring Boot and Spring Cloud

Google Cloud | via Coursera


Kotlin for Java Developers

JetBrains | via Coursera


Programming Mobile Services for Android Handheld Systems: Concurrency

Vanderbilt University | via Coursera


Programming Mobile Applications for Android Handheld Systems: Part 2

University of Maryland | via Coursera


Programming Cloud Services for Android Handheld Systems: Spring

Vanderbilt University | via Coursera


Programming Cloud Services for Android Handheld Systems: Security

Vanderbilt University | via Coursera


Cloud Computing Concepts

University of Illinois at Urbana-Champaign | via Coursera


Programming Mobile Applications for Android Handheld Systems: Part 1

University of Maryland | via Coursera


Programming Cloud Services for Android Handheld Systems

Vanderbilt University | via Coursera


React, JDBC, jQuery, RequireJS, Backbone.js, Liquibase, Terragrunt, REST APIs


Gradle, RabbitMQ, Amazon Elastic Container Service (Amazon ECS), Amazon Elastic Container Registry (ECR), Amazon Simple Queue Service (SQS), Apache Maven, Ansible, Jira, IntelliJ IDEA, Android Studio, Git, Apache Tomcat, Postfix, Java Card, ANTLR, Jenkins, CircleCI, Terraform, Zsh, Auth0


Spring Boot, JUnit, Spring, JPA, gRPC, .NET, Mono, JSF, Spring MVC, Bootstrap, ASP.NET, Redux, Jest, Spring Security, Hibernate, YARN, Play Framework


Groovy, Java, Kotlin, HTML, TypeScript, GraphQL, JavaScript, PHP, C#, ECMAScript (ES6), SQL, Scala, Bash, CSS


REST, Microservices, Test-driven Development (TDD), Role-based Access Control (RBAC)


Netflix, AWS Lambda, Android, Kubernetes, Visual Studio Code (VS Code), Linux, JEE, Java ME, Windows Mobile, iOS, Amazon Web Services (AWS), Docker, Apache Kafka, OS X, Azure, Firebase


MongoDB, Amazon S3 (AWS S3), MySQL, PostgreSQL, Spring Data, Microsoft SQL Server, Redis


Unix Shell Scripting, Single-page Applications (SPA), Web Services, SMPP, Orchestration, Single Sign-on (SSO), Okta, OpenID Connect (OIDC)

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