Software Engineer · Podium

Software engineer. Elixir at the core.

Olá. I build back-end systems that stay fast under load: GraphQL gateways, real-time messaging on Phoenix and OTP, credit engines, and the React interfaces on top of them. Building since 2020, working from Brazil.

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Elixir Phoenix GraphQL React PostgreSQL

Guilherme Xavier giving two thumbs up in a wood-panelled geodesic dome lounge — Fig. 01 · Lehi, Utah Hover for colorTap for color

01 · Experience

Nov 2024 – present

Podium

Software Engineer

Functional programming on business-critical services: an API gateway, messaging infrastructure and background processing.

Elixir/GraphQL API gateway serving production traffic
Real-time messaging on Phoenix LiveView and OTP
Cut processing latency with custom Oban schedulers, tuned Ecto queries and background-job best practices
Search and event pipelines on Elasticsearch and Kafka
Property-based testing across mission-critical services

Elixir Phoenix GraphQL React Elasticsearch Kafka

Aug 2021 – Nov 2024

Money Money Invest

Back-End Developer

Credit engine squad. Designed and shipped the services behind the loan application flow on Elixir and Phoenix.

Credit scoring APIs
Integrations with banks and financial services
Query optimization for performance and scale

Elixir Phoenix Next.js PostgreSQL

Dec 2020 – Jul 2021

Micks Brasil

Full Stack Developer

Mobile and web tools for field service management and route optimization.

iTecnico: React Native app for field technicians (connection adjustments, customer registration)
Micksell: web and mobile platform for real-time route tracking and vendor audits
REST APIs in Node.js for the mobile back ends

React Native Node.js REST JavaScript

02 · Expertise

Back-end systems

Scalable APIs on Elixir and Phoenix: GraphQL, messaging, and high-throughput server work on carefully tuned databases.

Elixir · Phoenix · GraphQL · PostgreSQL

Real-time & data

Messaging on Phoenix LiveView and OTP, search and event pipelines on Elasticsearch and Kafka, and background processing that stays predictable on Oban.

Phoenix · OTP · Kafka · Elasticsearch · Oban

Front-end

React and Next.js interfaces that are responsive, accessible and fast, built against APIs I understand end to end.

React · Next.js · React Native

03 · About

Started in computer vision. Stayed for the systems.

My first real programming was computer vision work in college. What kept me was the architecture underneath: how services talk, fail and recover.

Today that means functional programming with Elixir and Phoenix, GraphQL and PostgreSQL on the back end, and React on the front. I like problems where correctness and throughput both matter.

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Toolbox Rev 2026

Languages	Elixir, JavaScript, SQL
Frameworks	Phoenix, LiveView, React, Next.js, React Native, Node.js
Data & infra	PostgreSQL, Ecto, Oban, GraphQL
Practice	OTP, property-based testing, API design

04 · Education

2018 – 2022

Systems Analysis and Development

Degree program at IF Baiano with a focus on web and mobile development, databases and information security.

Dec 2022 – Feb 2023

Advanced English

Intensive program at Prime Cursos for advanced speakers: reading, writing, speaking and listening through complex texts.

05 · Contact

Say hello.

Back-end architecture, real-time systems, or a React front end that needs a solid API behind it. Email is fastest.

Email: contato@guixavier.com.br
Based: Guanambi, Bahia, Brazil
Links: LinkedIn GitHub