António Duarte
António Duarte

Hi, I'm António

Software Engineer

antonionpnduarte@gmail.com antonionduarte Lisbon, Portugal

Summary

Software Engineer at Paddle focused on backend systems, revenue recovery, recurring revenue analytics, and production service deployment across Go and Python/Django ecosystems.

M.Sc. candidate in Computer Science and Engineering at NOVA SST with a focus on distributed systems, parallel computing, algorithms, and programming language design.

Work Experience

  1. Retain Team

    Software EngineerLisbon, Portugal
    Feb 2026 - Present
    • One of the key decision-makers on decoupling Paddle Billing's Retain functionality from a legacy monolith into lean Go microservices, authoring 3 architectural proposals and 2 technical decision records that defined the strategy and protected $1.08M/month in recovered payments across 723 sellers.
    • Built a Go dunning microservice from zero to production, replacing a batch-based Python/Django system with an event-driven architecture using EventBridge and SQS.
    • Eliminated a critical dependency between payment recovery and the data pipeline that had previously caused a 37% drop in daily recovered payments during an infrastructure outage, from 272 to 171 payments/day.
    • Delivered 50+ PRs across 2 new services, owning application code in Go, Terraform/ECS infrastructure, event pipelines, auth configuration, API gateway routing, and BDD test suites.

  2. Metrics Team

    Junior Software EngineerLisbon, Portugal
    Jan 2025 - Feb 2026
    • Maintained and extended a data-intensive MRR processing pipeline in Python/Django, powering recurring revenue analytics for thousands of SaaS companies.
    • Overhauled internal migration tooling for onboarding payment providers by unifying candidate selection across integrations, automating data migration, and adding comprehensive test coverage.
    • Built pipeline observability infrastructure spanning metric alerting, operational dashboards, database connection resilience, stale-data detection, and checkpoint optimizations for billing data generation.
    • Led authoring and implementation of a technical decision record addressing critical security risks in external integration authentication, an architectural change spanning 40,000+ sellers using ProfitWell that aligned the system with security best practices.
    • Delivered 80+ PRs and resolved 30+ issues spanning reliability improvements, feature development, production investigations, and large-scale schema migrations.

  3. Cross-Organization Initiatives

    Software EngineerLisbon, Portugal
    2025 - Present
    • Authored decision records and developed global agentic skills encoding Paddle's architectural standards and internal library conventions, enabling safe, broad agentic development for code implementation and reviews across the engineering ecosystem.
    • Authored the decision record for introducing Profile-Guided Optimization across the Go service fleet and built an MVP CI workflow for automated weekly CPU profile collection.
    • Coordinated with security to unblock infrastructure access and designed a zero-effort team rollout, measuring 2-14% CPU reduction with no application code changes.

Education

M.Sc. in Computer Science and Engineering

Sept 2022 - Now
SST-UNL (NOVA School of Science and Technology)
Lisbon
  • Major in Distributed and Parallel Systems.
  • Minor in Algorithms and Programming Languages Design.

B.Sc. in Computer Science and Engineering

Sept 2019 - Aug 2022
SST-UNL (NOVA School of Science and Technology)
Lisbon

Research project that led to publishing a Scientific Paper in a national conference.

Erasmus+ Programme in Computer Science

Apr 2023 - Aug 2023
TU Dresden
Dresden
  • Scholarship-backed exchange programme.
  • Focus on Distributed Systems, Parallel Computing and Systems Dependability.

Presentations

Scientific Paper on Causal Consistency Simulation

Sept 2022
INForum
Guarda, Portugal

Scientific paper presentation on Accurate Simulation of Causal Consistency Replication protocols.

Technical Skills

Programming Languages

Python
Go
Rust
JavaScript
TypeScript
Java

Web Technologies

React
Next.js
Node.js
HTML
CSS
TailwindCSS

Databases

PostgreSQL
MySQL
SQLite
MongoDB
Redis
Elasticsearch

DevOps & Tools

Docker
Kubernetes
Terraform
AWS
ECS
Git
CI/CD
Linux
Bash

Concepts

Distributed Systems
Microservices
Event-Driven Architecture
Observability
Network Security
Agile Methodologies