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Daniel Bastos

Staff Software Engineer / Technical Lead

I turn product challenges into reliable systems designed to scale.

01 / About

My work connects engineering decisions to product outcomes.

From architecture to operations, I connect technical decisions to the experience they support.

How I work

I start with the product problem, not the technology. I understand the constraints, reduce complexity, and turn real needs into engineering decisions the team can execute and sustain.

I work alongside the team, from discussion through execution. I make trade-offs explicit, create the context for good decisions, and stay accountable for what reaches production.

02 / Experience

Staff Engineer

At RWS Integration, an infrastructure platform for B2B integrations, I was responsible for modernizing the company’s legacy system.

  • Restructured the codebase as an Nx monorepo.
  • Worked on the evolution of services built with AWS Lambda.
  • Built isolated, egress-only OpenVPN connectivity from customer-provided profiles, allowing the platform to access overlapping private networks securely and transparently.

Nx · Monorepo · AWS Lambda · OpenVPN · Networking · Legacy modernization

  1. Head of Backend
  2. Tech Lead
  3. Head of Product
  4. CTO

I joined to lead backend engineering and soon became the team’s primary technical reference, expanding my scope across engineering and product until taking on the CTO role.

  • Worked with the team to scale email infrastructure from zero to millions of messages per day using queues and AWS Lambda.
  • Contributed to a zero-downtime migration of the platform to Event Sourcing.
  • Modernized existing systems into an AWS Lambda-based microservices architecture.
  • Modernized infrastructure management with Terraform.

Queues · AWS Lambda · Event Sourcing · Email at scale · Product · AWS SQS · AWS SNS · AWS SES · Terraform · Apache Airflow · Amazon Redshift · OpenSearch

  1. Software Developer
  2. Senior Developer
  3. Tech Lead

At APOIA.se’s crowdfunding platform, I progressed from software developer to Tech Lead, combining hands-on delivery with team leadership.

  • Scaled payment processing through asynchronous queues with AWS SQS.
  • Helped build a new checkout in React that delivered significant improvements in backer conversion.
  • Led the team and modernized DevOps practices by introducing Terraform.

AWS SQS · React · Terraform · Payments · DevOps

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Mid-level Developer

Kino ContabilidadeCompany no longer operating

I worked at an online accounting startup, developing services for a platform that combined accounting and financial management.

  • Built microservices with Node.js, Laravel, and Redis.
  • Integrated with different Brazilian municipalities to enable electronic service invoice issuance for customers.

Node.js · Laravel · Redis · NFS-e · Integrations

Junior Developer

I worked at Zazo during its software-house phase, building PHP projects for clients including Abril Educação.

  • Developed web applications with PHP and CodeIgniter in a client-services environment.

PHP · CodeIgniter · Client projects

Technical Teaching Assistant

I held scheduled tutoring sessions and assisted teachers during COTEMIG’s technical classes.

  • Supported students in JavaScript, C#, and PHP through questions and practical exercises.
  • Developed technical communication and teaching skills by adapting explanations to different levels of knowledge.

JavaScript · C# · PHP · Technical education

IT Intern

My first professional experience in technology, working with IT support and infrastructure.

  • Performed computer maintenance and assembly.
  • Worked with network installation, configuration, and diagnostics.

Hardware · Maintenance · Networks · IT support

03 / Selected work

01

Event-driven marketing automation

Pingback

Event Sourcing · AWS SNS · AWS SQS · AWS Lambda · PostgreSQL · Parquet · Graph workflows

Problem

Pingback needed a workflow engine that could make its marketing platform more expressive and react to changes throughout each lead’s lifecycle.

Technical challenge

The platform needed to preserve a complete event history while evaluating graph-based workflows without coupling producers to automation logic. At scale, full replays and global searches against a single event stream also became operationally expensive.

Architecture / Approach

I designed an event-driven architecture in which domain changes were published through AWS SNS, buffered by AWS SQS, and processed with AWS Lambda. A dedicated consumer evaluated each event against the workflow graph, while every event was written to a global Event Store in PostgreSQL. As the stream grew, Apache Airflow materialized aggregate and projection tables in PostgreSQL for read use cases, avoiding global scans; the high-volume event history was later organized in Parquet for more scalable replay and analysis.

Result

The system sustained more than 50 million events per day and kept end-to-end delay around five seconds during peak load.

02

WYDBOT · Protocol research and sandboxed scripting

Independent technical project

Ghidra · Wireshark · Reverse engineering · Electron · Vite · QuickJS · Sandboxing · Network protocols

Problem

I used WYD as a constrained systems-research environment: reconstruct a proprietary protocol and explore an independent client that could be extended safely through user-written scripts.

Technical challenge

The project required reconstructing the network protocol without depending on the original client and executing third-party scripts without granting arbitrary access to the host machine.

Architecture / Approach

I reverse engineered the protocol with Ghidra and built a standalone game client with Electron and Vite. I also developed a Wireshark dissector that interpreted the already-decrypted traffic, exposing the protocol’s messages and fields for analysis and debugging. User scripts ran in an isolated QuickJS runtime that exposed only controlled APIs, reducing the attack surface of untrusted code.

Result

Six months of continuous execution validated the stability of the protocol implementation and script-isolation model, meeting the technical goals defined for the experiment.

03

Multi-tenant OpenVPN gateway

RWS Integration

OpenVPN · Linux network namespaces · veth · Policy routing · iptables · Docker · Amazon ECS · Amazon EC2 · Amazon S3 · AWS KMS · SSE-KMS · Egress-only networking

Problem

RWS Integration needed secure, transparent access to customers’ private networks while supporting overlapping address ranges.

Technical challenge

The solution had to be delivered in days, under tight budget constraints, without a managed firewall appliance, while handling CIDR collisions and asymmetric routing in AWS.

Architecture / Approach

I built a containerized gateway that isolated each customer tunnel in a Linux network namespace. veth pairs, NAT with iptables, and policy routing through a secondary ENI connected each OpenVPN tunnel to the VPC without leaking routes between tenants. Client profiles were provisioned from Amazon S3 using SSE-KMS with a dedicated AWS KMS key per customer. Connectivity was egress-only by design: tunnels were initiated from RWS, and routing and security controls allowed only return traffic for sessions initiated by the platform, preventing customers from initiating access to the AWS network.

Result

A new customer connection could be provisioned from an encrypted profile and its route definitions, with isolated tunnels, health checks, and connection recovery. The gateway met the delivery window and remained stable in operation.

04 / Toolbox

Languages & runtime
TypeScript · JavaScript · Node.js · Deno APIs, asynchronous services, and product systems
Interfaces & applications
React · Electron · Vite · QuickJS web interfaces, desktop clients, and isolated scripting
Data, search & orchestration
PostgreSQL · Redis · Parquet · Amazon Redshift · OpenSearch · Apache Airflow transactional data, event history, analytics, and pipelines
AWS & infrastructure
AWS stack · Terraform · Docker cloud architecture, infrastructure as code, and operations
Distributed architecture
Event Sourcing · Microservices · Event-driven architecture · Queues · Graph workflows scale, consistency, failure isolation, and asynchronous processing
Networking & security
OpenVPN · Linux networking · Routing · Network isolation secure connectivity and environment isolation
Reverse engineering
Ghidra · Wireshark · Binary and network analysis protocol reconstruction, traffic inspection, and debugging

05 / Contact

Let’s build systems that hold up.

Email
LocationBelo Horizonte, Brazil
Work modelRemote · Hybrid · On-site