Pere is available for hire
Hire PerePere Casafont
Verified Expert in Engineering
Java Developer
Reus, Spain
Toptal member since May 6, 2015
Bio
Pere is a software architect with over a decade of experience working on JVM-based back-end products ranging from custom binary protocols to REST APIs on Ktor. He has a remarkable ability to work on and get the best out of any kind of project. Once Pere is in a team, they will gradually notice an increase in that team's cohesion and performance, no matter his position in it. He is very communicative, proactive, and committed to the projects he works on.
Portfolio
Yara International
Java, Kotlin, REST APIs, Microservices, Amazon Web Services (AWS), AWS Lambda...
Personio - Main
Kotlin, PHP, Amazon Web Services (AWS), Microservices Architecture, Docker...
EMME
YouTrack, TeamCity, Kotlin, Ktor, KOIN, Exchange API, APIs, WebSockets, Sockets...
Experience
- SQL - 14 years
- Java - 14 years
- Kotlin - 6 years
- Docker - 4 years
- Reactive Programming - 4 years
- Ktor - 4 years
- Gradle - 3 years
- IntelliJ IDEA - 3 years
Work Experience
Senior Full-stack Engineer
2023 - 2025
Yara International
- Redesigned and stabilized back-end architecture by streamlining AWS Lambda microservices using Quarkus to improve reliability and maintainability.
- Led the Android team through the final development phase, ensuring timely deliveries and alignment with project goals.
- Fostered a collaborative team environment by mentoring peers and promoting open communication, resulting in stronger team cohesion.
Technologies: Java, Kotlin, REST APIs, Microservices, Amazon Web Services (AWS), AWS Lambda, PostgreSQL, Quarkus, API Gateways, Amazon Simple Queue Service (SQS), Amazon RDS, RFID, CI/CD Pipelines, Android, Jetpack Compose, Front-end, Full-stack Development, Solution Architecture
Senior Back-end Engineer
2022 - 2022
Personio - Main
- Migrated legacy PHP services to Kotlin microservices.
- Drove back-end side of the team's new features, coordinating with the front-end team.
- Collaborated with fellow Windows users to improve the developer experience.
Technologies: Kotlin, PHP, Amazon Web Services (AWS), Microservices Architecture, Docker, Kubernetes, Spring Boot
Tech Lead and Product Owner
2021 - 2022
EMME
- Designed the back-end architecture using microservices with a central coordinator service.
- Created an exchange trading bot controlled by the coordinator with cryptography-provable instructions linked to the blockchain.
- Built a very easily maintainable CI/CD framework for the full stack with TeamCity's Kotlin DSL.
- Managed and supported the front-end team (both design and implementation).
Technologies: YouTrack, TeamCity, Kotlin, Ktor, KOIN, Exchange API, APIs, WebSockets, Sockets, PostgreSQL, Architecture, Docker, Docker Compose, RabbitMQ, Prometheus, Grafana, Back-end, Node.js, TypeScript, REST APIs, Back-end Development, Leadership, Full-stack, Software Architecture, Technical Leadership, Team Leadership, JavaScript, CSS, HTML5, Redis, Scrum, Linux, Network Programming, Client-server Model, Parsers, Gradle, Multithreading, Concurrent Programming, Reactive Programming, CentOS, Microservices, SSL, Minimum Viable Product (MVP), MVP Design, API Integration, Databases, REST, Protobuf, Digital Banking, Crypto, Desktop App Development, Front-end, Full-stack Development, Solution Architecture, System Architecture
Tech Lead
2019 - 2022
VeriBlock
- Maintained and developed the node core of a unique blockchain.
- Implemented the Altchain PoP miner, which connects to both VeriBlock nodes and Altchain nodes and mines the altcoins using VeriBlock's Proof of Proof consensus.
- Refactored the peer-to-peer communication module of the blockchain nodes to use Ktor sockets and coroutine-based events.
- Developed a DSL library that enabled developers to create CLIs very easily.
- Led the initiative to migrate the company's project management from Jira to YouTrack with very positive results.
- Created a PoP mining back end that enabled Bitcoin wallets to earn VeriBlock coins when making transactions (PoP subsidies).
- Built a company-wide CI/CD DSL (TeamCity and Kotlin) project that automatically created all build configurations for all repositories.
- Fixed a product that kept having severe issues by completely refactoring it. That also sped up the addition of new features and prevented many future potential problems.
- Created BFI, a back end that would query all blockchains (Bitcoin, VeriBlock, Altchains) via direct connection to their nodes, which would scan every transaction to find proof of proof endorsements and rebuild the blockchains based on them.
- Built and led several other full-stack products from start to finish.
Technologies: Java, Kotlin, TeamCity, YouTrack, Ktor, KOIN, SQLite, PostgreSQL, Git, Blockchain, APIs, Architecture, WebSockets, Sockets, Back-end, Node.js, TypeScript, REST APIs, Back-end Development, Leadership, Full-stack, Software Architecture, Technical Leadership, Team Leadership, JavaScript, CSS, HTML5, Scrum, Linux, Network Programming, Client-server Model, Parsers, Gradle, Multithreading, Concurrent Programming, Reactive Programming, CentOS, SSL, Minimum Viable Product (MVP), MVP Design, API Integration, Databases, gRPC, REST, Protobuf, Crypto, Desktop App Development, Front-end, Full-stack Development, Solution Architecture, System Architecture
Senior Developer
2019 - 2019
Docpaid
- Converted the Groovy codebase into Kotlin, fixing hundreds of bugs.
- Provided smooth conversion, and everything stood up and running.
- Got a delayed project back on track in less than a month.
Technologies: Groovy, Kotlin, Architecture, Back-end, REST APIs, Back-end Development, Software Architecture, Technical Leadership, HTML5, Scrum, Linux, Gradle, APIs, Databases, REST, Apache Tomcat, Digital Banking
Senior Back-end Developer
2018 - 2019
BTCMarkets
- Created tests for previously existing software using Spok.
- Built a new core library using Kotlin while keeping full Java compatibility with all other modules and services.
- Designed a completely new set of endpoints for interacting with the whole back end.
- Collaborated in the creation of an SSO from scratch.
Technologies: Java, Groovy, Spring, Unit Testing, Amazon Web Services (AWS), Single Sign-on (SSO), Back-end, REST APIs, Back-end Development, Software Architecture, HTML5, Redis, Spring Data JPA, Scrum, Apache Maven, APIs, Databases, REST, Apache Tomcat, Digital Banking, Crypto
CTO and Software Architect
2017 - 2019
Task & Time
- Designed and implemented the company's main product back end from scratch.
- Designed and implemented the data model using Hibernate and MongoDB (hybrid data model).
- Implemented a complex task schedule optimization algorithm.
- Created an Angular web application for the company's first product, which accesses the main back end.
- Designed the second product's data structures and API endpoints.
- Managed a team of two other developers and a QA remotely with scrum sprints.
Technologies: SQL, Docker, Spring REST, JUnit, Git, Kotlin, Ionic, Angular, MongoDB, MySQL, Hibernate, Spring Boot, Java, GUI Development, Architecture, CTO, Back-end, Node.js, TypeScript, REST APIs, Back-end Development, Leadership, Full-stack, Software Architecture, Technical Leadership, Team Leadership, JavaScript, CSS, HTML5, Redis, Spring Data JPA, Spring, Scrum, Linux, Android, Parsers, Gradle, Multithreading, Concurrent Programming, CentOS, SSL, Minimum Viable Product (MVP), APIs, MVP Design, API Integration, Databases, REST, Front-end, Full-stack Development, Solution Architecture, System Architecture
Back-end Software Developer
2018 - 2018
Tremor
- Refactored all the REST endpoints to decrease their amount of code and readability.
- Converted all the hardcoded failure entity returns into exceptions, for which I implemented a handler.
- Moved a few enumerations declared as database tables to be actual Java enumerations properly mapped and referenced in JOOQ.
- Unified several services with duplicated code and their data transfer objects (DTO).
- Created an integration test suite with MockMvc and EmbeddedPostgres.
- Implemented several endpoints, features, and tests on demand.
Technologies: SQL, Docker, Spring REST, Git, PostgreSQL, JOOQ, Spring Boot, Java, Fintech, Back-end, REST APIs, Back-end Development, Software Architecture, Scrum, Gradle, Apache Maven, APIs, Databases, REST, Apache Tomcat, Digital Banking
Software Architect
2017 - 2017
Apoyo al Estudio
- Designed and implemented the company's main product back end from scratch.
- Architected the API endpoints and worked alongside with front-end developer.
- Made design of the product's data model and implemented it with Hibernate.
- Implemented Spring Controller unit tests with MockMvc.
Technologies: SQL, Docker, Spring REST, JUnit, Git, Kotlin, MySQL, Hibernate, Spring Boot, Java, GUI Development, Architecture, Back-end, Node.js, TypeScript, REST APIs, Back-end Development, Leadership, Full-stack, Software Architecture, Technical Leadership, Team Leadership, JavaScript, CSS, HTML5, Redis, Spring Data JPA, Spring, Scrum, Linux, Parsers, Gradle, Multithreading, Concurrent Programming, CentOS, SSL, Minimum Viable Product (MVP), APIs, MVP Design, API Integration, Databases, REST, Front-end, Full-stack Development, Solution Architecture, System Architecture
Senior Software Engineer
2016 - 2017
Operartis
- Converted from a database access singleton to decentralized autonomous organizations (DAOs) using Java Database Connectivity (JDBC).
- Reorganized project packaging and dependencies with Gradle.
- Created in-memory data managers for fast data lookup.
- Implemented a filter framework to filter in-memory data according to a flexible set of conditions, using binary searches.
- Wrote a set of JavaFX applications for data display.
- Converted the whole project into a Spring back end.
- Created a web app interface using Angular. It included custom diagrams drawn "manually" with lines.
Technologies: SQL, Docker, Spring REST, JUnit, Git, JavaFX, Kotlin, Hibernate, Angular, Spring Boot, Gradle, MySQL, Java, Fintech, GUI Development, Artificial Intelligence (AI), Architecture, Back-end, REST APIs, Back-end Development, Leadership, Software Architecture, Technical Leadership, JavaScript, CSS, HTML5, Redis, Spring Data JPA, Scrum, Linux, Parsers, Multithreading, Concurrent Programming, SSL, Minimum Viable Product (MVP), APIs, API Integration, Databases, REST, Digital Banking, Desktop App Development, Front-end, Full-stack Development, Solution Architecture, System Architecture
Back-end Software Developer
2015 - 2017
James Evans and Associates
- Created a tool that would parse testing spreadsheets and develop thousands of JUnit tests from that data.
- Implemented JSON format export for the unit tests tool.
- Developed back-end modules of a Spring enterprise project.
- Created Database Access Objects with the MyBatis library.
- Maintained and developed a user interface project with JavaFX.
Technologies: SQL, Spring REST, JUnit, EasyMock, Oracle, MyBatis, Spring, Java, Fintech, Back-end, REST APIs, Back-end Development, Software Architecture, Spring Data JPA, Parsers, Eclipse IDE, Apache Maven, Databases, REST
Software Architect
2015 - 2016
Synesthetic Visuals
- Created a graphical interface which would create customizable 3D letters in a canvas. The 3D view is surrounded with controls to perform a big set of different modifications to the letters, as well as animations.
- Combined Java Swing with Java OpenGL (JOGL) to display the 3D canvas in the center of the app.
- Created a 3D engine and its shaders, including geometry shaders and shadows.
- Handled over 50 different settings and configurations for the displayed results.
- Created an animation editor in which you could set key points for every configuration at any time.
- Implemented a render animation functionality that would store the result in a high-quality video file.
Technologies: SQL, Git, OpenGL, Swing, Java, GUI Development, Architecture, Software Architecture, CSS, HTML5, Parsers, Eclipse IDE, Multithreading, Concurrent Programming, Minimum Viable Product (MVP), MVP Design, Databases, Desktop App Development, Front-end, Full-stack Development, Solution Architecture, System Architecture
Founder
2011 - 2016
L2Tenkai
- Hosted and maintained an open-source MMORPG server.
- Developed the server-side of new game features, which included all the client-server communications and logic, as well as designing the best way to fit them into the existing architecture.
- Refactored more than twenty core modules of a big existing codebase (over 2,000 classes).
- Created a development tool in Java Swing to manage and bulk edit static data with ease, which drastically increased the team's development speed.
- Created a game launcher in C#, which handled the authentication communicating with a PHP API, which at its end communicated with the Java game server.
- Led a team of up to three developers and eight community managers.
Technologies: SQL, Git, JavaFX, Kotlin, Windows Server, PHP, C#, MySQL, Java, GUI Development, Architecture, Back-end, Back-end Development, Python, Leadership, Software Architecture, Technical Leadership, Team Leadership, JavaScript, CSS, HTML5, .NET Core, Linux, Network Programming, Client-server Model, Parsers, Subversion (SVN), Eclipse IDE, Multithreading, Concurrent Programming, Microsoft Visual Studio, SSL, Minimum Viable Product (MVP), APIs, MVP Design, API Integration, Swing, Databases, Desktop App Development, Front-end, Full-stack Development, Solution Architecture, System Architecture
Administrator and Developer
2007 - 2012
L2TnS
- Hosted and maintained an open-source MMORPG server.
- Synchronized the software with the project’s repository frequently.
- Developed and maintained the home website, which displayed in-game real-time data.
- Created an in-game events engine with high scalability.
- Administrated a MySQL database with over eighty tables.
- Led a team of up to two developers and five community managers.
Technologies: SQL, Windows Server, PHP, MySQL, Java, GUI Development, Architecture, Back-end, Back-end Development, Python, Leadership, Software Architecture, Technical Leadership, Team Leadership, JavaScript, CSS, HTML5, Linux, Network Programming, Client-server Model, Parsers, Subversion (SVN), Eclipse IDE, Multithreading, Concurrent Programming, Microsoft Visual Studio, SSL, Minimum Viable Product (MVP), MVP Design, Swing, Databases, Desktop App Development, Front-end, Full-stack Development, Solution Architecture, System Architecture
Project History
Ludoya
This is a full-stack application I have been building singlehandedly since November 2022. The back end uses Kotlin (Ktor, Koin, and Exposed), and the front end is in Angular (pure Angular and Material).
I also built a small infrastructure that includes CI/CD (TeamCity), metrics and logging (Grafana, Prometheus, and Loki), project management (YouTrack), and multiple app environments for testing purposes.
I also built a small infrastructure that includes CI/CD (TeamCity), metrics and logging (Grafana, Prometheus, and Loki), project management (YouTrack), and multiple app environments for testing purposes.
Liquidity Exchange
An exchange platform where users can buy and sell third-party crypto exchanges' liquidity.
As the tech lead and back-end architect, I led a team of eight people, designed and implemented most of the critical functionality, and created all the infrastructure to support the platform.
As the tech lead and back-end architect, I led a team of eight people, designed and implemented most of the critical functionality, and created all the infrastructure to support the platform.
P2P Engine for a Blockchain Node and SPV
https://github.com/VeriBlock/nodecore/tree/master/nodecore-p2pVeriBlock is an L1 blockchain that has its own network running.
I refactored the peer-to-peer communication engine, the nodes used to unify it with the SPVs, and migrated the code to a modern library using Ktor and Coroutines.
I refactored the peer-to-peer communication engine, the nodes used to unify it with the SPVs, and migrated the code to a modern library using Ktor and Coroutines.
Time Management App for Students
https://taskntime.org/en/studeam-4/An Angular app with a Kotlin and Spring back end. The app asks the user for their homework, including the estimated amount of effort and deadlines, and the application organizes the time in the most optimal way.
I was the CTO of this small startup, having taken all the significant technology decisions and implemented the most critical logic on a full-stack scope.
I was the CTO of this small startup, having taken all the significant technology decisions and implemented the most critical logic on a full-stack scope.
Education
2010 - 2014
Bachelor's Degree in Video Games Development
DigiPen Institute of Technology - Redmond, Washington, USA
2006 - 2010
Bachelor's Degree in Computer Engineering
Universitat de Vic - Vic, Barcelona, Spain
Skills
Libraries/APIs
Spring REST, REST APIs, OpenGL, Protobuf, MyBatis, EasyMock, JOOQ, DirectX, Sockets, Exchange API, Node.js
Tools
Gradle, Git, IntelliJ IDEA, Subversion (SVN), Eclipse IDE, Microsoft Visual Studio, Apache Maven, TeamCity, YouTrack, Docker Compose, RabbitMQ, Grafana, GitHub, Apache Tomcat, Amazon Simple Queue Service (SQS)
Languages
Kotlin, Java, HTML5, SQL, C++, C, GLSL, C#, TypeScript, JavaScript, CSS, Python, Ada, Pascal, PHP, Groovy, HTML
Frameworks
Ktor, JUnit, Spring Boot, Hibernate, Spring, Swing, gRPC, Angular, Ionic, KOIN, .NET Core, Material UI
Paradigms
REST, Reactive Programming, Concurrent Programming, Scrum, Desktop App Development, Unit Testing, Management, Microservices Architecture, Microservices
Platforms
JavaFX, Docker, Windows Server, Blockchain, Windows, CentOS, Oracle, Linux, Android, Amazon Web Services (AWS), AWS Lambda, Kubernetes
Storage
PostgreSQL, MySQL, Databases, Spring Data JPA, Redis, MongoDB, SQLite
Other
Software Architecture, Network Programming, Multithreading, Parsers, Client-server Model, Animation, Fintech, Architecture, APIs, Back-end, Back-end Development, Full-stack, Technical Leadership, Minimum Viable Product (MVP), MVP Design, API Integration, Crypto, Cloud Architecture, Web Applications, Front-end, Full-stack Development, Solution Architecture, System Architecture, GUI Development, Artificial Intelligence (AI), CTO, Leadership, Team Leadership, SSL, Digital Banking, Content Delivery Networks (CDN), JetBrains IDE, WebSockets, Prometheus, Single Sign-on (SSO), Open Source, Networking, Coroutines, Quarkus, API Gateways, Amazon RDS, RFID, CI/CD Pipelines, Jetpack Compose
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