Infrastructure & Security Engineer
Infrastructure, security
& automation.
I build and maintain systems that connect people,
access, and operations.
Legioner Solutions
Access automation and security engineering for a community application.
20,000+ community members
~70% less manual administration
Membership-based scale; project-reported reduction estimate.Resume / Leandro Pareja
Experience & capabilities.
Hands-on systems administration, application security,
and access automation.
Experience
October 2023 – August 2025Founder | Systems Administration and Application SecurityLegioner Solutions | Boca Raton, FL
Hours per week: Approx. 35–40 | Series/Grade: N/A (private sector)
- Performed systems administration across production servers and multiple nodes supporting 20,000+ active users; managed server configurations, application deployments, maintenance, and technical troubleshooting.
- Engineered API integrations and real‐time data pipelines using MongoDB, JSON, and the Google Sheets API; managed server logs and user requests, resolved data integrity issues, and maintained technical documentation.
- Automated Identity and Access Management (IAM) and role‐based access control (RBAC) workflows, reducing administrative overhead by 70% while improving user verification and account administration.
- Led a distributed team of contributors, established technical priorities, and coordinated feature development, bug fixes, and release schedules across time zones.
- Monitored servers and multiple nodes through log review, error tracking, and availability checks; maintained 99.9% uptime by investigating service disruptions, resolving faults, and restoring reliable operations.
- Developed React dashboards deployed through Railway and Vercel to centralize server activity and operational data, enabling nontechnical stakeholders to monitor production environments and player engagement.
- Integrated Epic Online Services (EOS) and Steam APIs for authenticated server and player data; assessed undocumented authentication behavior through controlled testing and documented observed security risks.
- Managed a $300 monthly infrastructure budget and maintained regular communication with users and contributors to address technical needs and support reliable service delivery.
Technical projects
2025Application Security & Network Traffic AssessmentPersonal Project | Self-Directed
- Conducted black‐box analysis of client‐server communications; analyzed outbound network traffic, DNS behavior, telemetry, and host‐level traffic controls to assess application behavior and authentication risks.
- Assessed EOS and Steam authentication workflows using public documentation, controlled testing, and direct observation to identify weaknesses in identity verification and third‐party service interactions.
- Discovered and documented an authentication‐related information exposure vulnerability involving player and server data in EOS/Steam workflows; responsibly disclosed the findings to Studio Wildcard.
2025Unreal Engine 5 Security Assessment & Responsible DisclosurePersonal Project | Self-Directed
- Developed a custom Unreal Engine 5 mod using Blueprint scripting; examined client‐side architecture and command execution behavior to support application security testing and vulnerability assessment.
- Identified and documented an access control bypass that allowed unauthenticated users to load unapproved mods onto official multiplayer servers, circumventing restrictions on unauthorized content.
- Responsibly disclosed the vulnerability to Studio Wildcard, documenting the observed behavior and potential security impact to support remediation and reduce the risk of unauthorized server content.
Technical capabilities
Education
B.S. Data Science and Analytics
Florida Atlantic University
GPA 3.80 / 4.00 · Dean’s List, Spring 2026
A.S. Computer Programming
Palm Beach State College
GPA 3.50 / 4.00
Certifications & development
CompTIA SecurityX (formerly CASP+) Certification
Earned September 2026
Cisco Certified Network Associate (CCNA)
In progress
Microsoft Certified: Azure Administrator Associate (AZ-104)
In progress
LinkedIn Windows 11: Configure and Support Core Services Certification
Earned September 2026LinkedIn Windows 11: Administration Certification
Earned September 2026Global Career Accelerator Data Analysis Certification
Earned July 2026Global Career Accelerator Data Visualization Certification
Earned July 2026Global Career Accelerator Intercultural Skills Certification
Earned July 2026Global Career Accelerator AI Professional Skills Certification
Earned July 2026Legioner Solutions / Engineering case study
Access automation
& security.
Event-driven application engineering for a 20,000+ member community.
Community scale; membership-based count.
Project-reported estimate across automated activities.
I built structured access and operations workflows connecting user identity, role assignment, persistent requests, and staff actions in one application.
Node.js · JavaScript · discord.js v14 · MongoDB
Google Sheets API · JSON persistence · async-mutex
The operational challenge
Membership approvals, access requests, and resource fulfillment relied on recurring staff coordination. The application replaced free-form intake with guided requests, explicit status, and completion notifications, making outstanding work easier to track.
My engineering scope
Application and integration development spanning event routing, command and form handlers, role-based checks, MongoDB persistence, spreadsheet synchronization, operational displays, and automated notifications.
Staff retained responsibility for approval decisions and in-game fulfillment. The automation coordinated the workflow around those decisions.
Architecture & data flow
Identity context moves through event routing, handler-specific checks, persistent workflow state, and staff-facing output. Select any node to explore an illustrative proof of concept.
Telemetry & integrations
Configured tracker messages pass through sender and channel matching into parsed operational state. A public server feed supplies population and metadata for scheduled displays. External database reads support player analytics and leaderboard aggregation.
Google Sheets connects through a service account and import/export utilities. Local JSON stores tasks, timers, and snapshots; in-memory maps and sets hold temporary state.
Simplified logical architecture. Authorization checks are distributed across selected handlers. Local JSON, locks, and temporary state are process-scoped. External services supply identity and telemetry.
Security controls in practice
Identity & authorization
The platform supplies authenticated user identity with each interaction. Selected commands check configured role groups before modifying membership state. Cross-community onboarding checks primary-community membership and the required role before assigning secondary roles.
Request lifecycle
Guided inputs collect the target server and character details. Applicable workflows check for an existing pending request, create an incomplete MongoDB record, and publish a staff work card.
- Collect the request and check pending state.
- Persist the request and present it to staff.
- Staff approve and fulfill the request.
- Record completion, refresh the queue, disable completed controls, and notify the requester.
Data integrity & concurrency
Character-record removals use a process-local mutex to serialize the helper’s read/modify/write path. Updates include a lastModified marker; spreadsheet imports skip retained records already marked as manually corrected.
These controls reduce specific overwrite paths while preserving intentional staff edits. They are process-local safeguards, not distributed locking.
Operational safeguards
Typed command options, required form inputs, duplicate-pending-request checks, private responses in selected workflows, configured telemetry-source matching, and RAW spreadsheet writes support predictable operations. Persisted reminders restore scheduled work after application restarts.
Engineering judgment & next steps
The architecture separates workflow automation from human fulfillment. The next hardening priorities are:
- Consistent authorization on every mutation.
- Atomic request deduplication.
- Revision-checked database writes.
- Retry and reconciliation tracking when database updates succeed but notifications fail.
This work connects identity, access workflows, backend logic, data persistence, and operational troubleshooting in a community application.
Adapted from my supplied Legioner Solutions case study. The original PDF is available above. Homepage network activity is a separate visualization using simulated events.
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