Summary
Overview
Work History
Education
Skills
Certification
Languages
Timeline
COURSES
SeniorSoftwareEngineer

Jonathan Sequeira

Conroe,TX

Summary

Engineer with 7+ years of experience delivering software in fin-tech and SaaS, specializing in React, TypeScript, and Node.js. Background spans full-stack development, cloud platforms (Azure and AWS), and building secure, large-scale applications. Led efforts to reduce security vulnerabilities by over 90%, guided multi-month TypeScript migrations, and introduced micro-frontend architecture to break down monolithic systems. Experienced with CI/CD automation, cross-team collaboration, and translating complex requirements into maintainable, production-ready solutions.

Overview

14
14
years of professional experience
1
1
Certification

Work History

Senior Software Engineer

Synchrony Financial
03.2024 - Current
  • Transitioned to Synchrony as part of the Lending team acquisition (100+ engineers), retaining the same responsibilities during the handover.
  • Translated existing Azure pipelines and services into AWS equivalents, gaining hands-on experience with cloud migrations and cross-platform deployments.
  • Led disaster recovery implementations across East and West regions to meet compliance requirements for critical applications.
  • Maintained existing systems in a maintenance and compliance mode after Synchrony decided to sunset Ally’s lending technology stack.
  • Focused on bug fixes, stability improvements, and regulatory support while customer data was migrated from Ally systems into Synchrony’s platforms.
  • Oversaw the final sunset of the monolith, ensuring a smooth transition and minimal disruption for business stakeholders.

Senior Software Engineer

Ally Financial
03.2022 - 03.2024
  • Mentored junior developers and guided them through code reviews, sprint planning, and deployment workflows.
  • Resolved 1,400+ DAST security issues in a large React/TypeScript monolith by implementing Content Security Policy (CSP), fixing XSS vectors, and adding CSRF protection — reducing unresolved findings to fewer than 20.
  • Led the JavaScript-to-TypeScript migration effort (6–8 months), working with backend teams to align API contracts with Swagger specs, upgrade v1 → v2 calls, and enforce runtime validation with Zod.
  • Designed and rolled out a microfrontend strategy using Webpack Module Federation, enabling dashboards and the authentication app (Next.js) to be split from the monolith and deployed independently on CDNs.
  • Built custom CI/CD pipelines in Azure DevOps for each microfrontend, ensuring reliable builds and deployments.
  • Automated infrastructure deployments with Terraform, reducing manual work and improving consistency across environments.

Software Engineer

USAA
09.2021 - 03.2022
  • Rebuilt pieces of a large React app into smaller, self-contained widgets, making the codebase easier to maintain and faster to update.
  • Helped the team switch from plain JavaScript to TypeScript, writing conversion guides and updating modules so newer work was more predictable and less error-prone.
  • Added missing tests with Jest and Cypress, which raised overall coverage by about 20% and caught UI bugs earlier in development.
  • Shipped profile features used across multiple business areas, coordinating with other engineers so changes worked smoothly in different parts of the system.
  • Took on Spring Boot Java tickets when needed — even outside my main stack — to keep projects moving and show flexibility with backend tasks.

Software Engineer

Adsync Technologies
05.2021 - 09.2022
  • Sole maintainer of a Java/JSP acquisition system used by Naval Supply Command to process requests for ship parts, manuals, and maintenance documentation.
  • Fixed bugs and delivered new features to support ship, submarine, and carrier acquisition workflows, each with unique approval logic tied to vessel type.
  • Built and updated digital forms that allowed engineers, logistics staff, and commanding officers to collaborate in one system, with digital signatures and approval tracking for funding and fulfillment.
  • Worked directly with Oracle DB (via Toad) to debug stored procedures and ensure reliable data handling for approvals and cost calculations.
  • Partnered with end users (engineers and logistics personnel) to translate operational requirements into system updates, keeping acquisition requests flowing without disruption.

Software Engineer

GDIT
04.2019 - 05.2021
  • Developed and maintained a React/.NET application that automated ACT/SAT reimbursement workflows for military personnel. Designed data pipelines to fetch and serialize exam funding data from SharePoint Excel sheets into SQL databases, applying business logic to calculate costs based on rank, years of service, command, and OCONUS status.
  • Implemented backend services in Node.js/Express and C# APIs to support exam funding logic, database updates, and secure integration with stakeholder systems.
  • Created and secured RESTful APIs with JWT-based authentication, enabling authorized access to sensitive reimbursement and funding data.
  • Engineered an FAA drone-tracking dashboard: built a React frontend and Node.js/Express backend that consumed ArcGIS data pipelines from data engineers, rendering 3D maps of drone flight paths using ArcGIS JavaScript libraries.
  • Collaborated with FAA engineers to provide geospatial data visualizations of drone trajectories over airport airfields, supporting analysis of mitigation strategies (signal jamming, laser interception).
  • Sole developer on the frontend and middleware stack, delivering end-to-end UI and API layers from scratch in a two-person agile team.

Junior Software Engineer

Ryze Agency
08.2018 - 03.2019
  • Built and deployed a call center tracking dashboard using Node.js and Express, implementing RESTful endpoints to manage call data and user analytics.
  • Designed and maintained server-side logic for API integrations with third-party services, improving automation and data flow between systems.
  • Optimized Express middleware for request validation, authentication, and error handling, increasing reliability and scalability.

Petty Officer Second Class

United States Navy
12.2011 - 06.2017
  • Managed high-stakes fuel operations using HMI software on naval aircraft carriers.
  • Provided local IT and systems support, reinforcing hardware and network security.
  • Supervised training programs for junior personnel, enhancing operational readiness and team performance.

Education

B.A. - Computer Science

Florida International University
Miami, FL
10.2021

Skills

  • Nodejs
  • JavaScript
  • React
  • Redux
  • Jest
  • Cypress
  • Git
  • C# NET
  • Java
  • SQL
  • Azure DevOps
  • Web application development
  • Amazon web services
  • Development lifecycles
  • API development experience
  • NET development

Certification

  • Microsoft Technology Associate August 2020

Languages

English
Native or Bilingual
Spanish
Native or Bilingual

Timeline

Senior Software Engineer

Synchrony Financial
03.2024 - Current

Senior Software Engineer

Ally Financial
03.2022 - 03.2024

Software Engineer

USAA
09.2021 - 03.2022

Software Engineer

Adsync Technologies
05.2021 - 09.2022

Software Engineer

GDIT
04.2019 - 05.2021

Junior Software Engineer

Ryze Agency
08.2018 - 03.2019

Petty Officer Second Class

United States Navy
12.2011 - 06.2017

B.A. - Computer Science

Florida International University

COURSES

Full Stack Web Development, Florida Vocational Institute March 2018 — November 2018

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