# Alejandro Zaragoza > Senior Software Engineer | Payments, Transaction Processing, Distributed Systems | ex-Block, AWS, Amazon, Adobe Location: Claremont, California, United States Profile: https://flows.cv/alejandrozaragoza Software Engineer with ~8 years of experience building scalable backend systems, financial infrastructure, AWS cloud services, and full-stack applications. Experience across card transaction processing, developer platforms, cloud infrastructure, and consumer-scale systems at Block, Amazon Web Services (AWS), Amazon, and Adobe. Kotlin, Java, C++, JavaScript, Typescript, React, SQL/NoSQL, Kafka, AWS (Redshift, DynamoDB, Lambda, API Gateway, VPCs, RESTful Services, Micro services, etc.) ## Work Experience ### Senior Software Engineer @ Cash App Jan 2023 – Present - Built and operated Tier-0 backend systems for real-time card transaction processing, converting issuer-specific authorization traffic into a common internal flow for Cash App and Square card products. - Drove migration of the card-locking functionality from the ledger service into the transaction service, including new lock-state APIs, safe cutover synchronization, and feature-flagged rollout across 4+ dependent Tier-0/Tier-1 services. - Developed overdraft balance stand-in capabilities that preserved transaction authorizations during ledger-service outages, and added shadow-mode metrics to validate decision accuracy before launch. - Supported the launch of Square Card UK by integrating with internal risk systems for UK authentication requirements and building a reliable currency-conversion API for UK card transactions. - Led response during major SEV incidents for critical card-processing infrastructure by quantifying customer impact, driving technical triage, mitigating active issues, and supporting long-term remediation. ### Software Development Engineer II @ Amazon Web Services (AWS) Jan 2021 – Jan 2023 Lead architect on new designs for numerous services in AWS. Teams: - AWS Documentation - AWS Transfer Family: https://aws.amazon.com/aws-transfer-family - Led architecture and development of internal backend services, driving design reviews, implementation planning, and delivery across infrastructure-focused projects. - Designed and built a build-system service managing 5,000+ code packages for AWS Documentation Localization, replacing manual build submission workflows and reducing time-to-detect localization-breaking errors through earlier automated validation and failure reporting. - Built backend services for enterprise managed file transfer use cases, including support for SFTP, FTPS, and AS2 integrations. - Improved service reliability through monitoring, alerting, canaries, and integration testing for production systems with a high operational excellence bar. ### Backend Software Engineer @ Point Card Jan 2021 – Jan 2021 - Designed and implemented system to update user data attributes on third party system - NodeJS development for GraphQL API service: features, operational improvements, and bug fixes ### Software Development Engineer II @ Amazon Jan 2021 – Jan 2021 | Santa Monica, California, United States ### Software Development Engineer @ Amazon Jan 2020 – Jan 2021 | Santa Monica, California, United States - Longest tenured engineer on a growing team. We own a reward-driven advertising product: Moments. - Lead the team by designing and implementing features for our product using numerous AWS resources. Own all maintenance and operation of our systems. - Drive advertiser campaigns from development, through execution, and to completion. - Teach and develop other engineers on the team on our product and systems, how to be a software engineer at Amazon, and software development in general. Tech Stack: Java, React, Javascript, Typescript, SQL, AWS Resources (Lambda, Dynamo, Redshift, VPCs, APIGateway, Cloudwatch, etc.) ### Software Engineer @ Adobe Jan 2018 – Jan 2020 | San Francisco, California FullStack Software Engineer on AdobeXD: a user experience design tool for desktop (Mac & Win) and web. TechStack: C++, Objective-C, JavaScript, React, ChromeV8 Implemented features throughout entire stack. Unit & Integration tests with high coverage across all platforms. Features include: Language Localization, Keyboard Shortcuts, Analytics, Concurrent Operations Experience using native APIs. Experience working cross team and organization with Program Managers, Designers, Operations, Quality Assurance, etc. ### Software Engineer @ IBM Jan 2017 – Jan 2018 | Tucson, AZ Software engineer for the Device Adapters team. Added new functionality to KMIP testing utility used to test IBM servers, written in C. Won 2nd place in IBM hackathon for prototype idea for simplifying online learning. ### Software Engineer @ American Express Jan 2017 – Jan 2017 | Phoenix, Arizona Area The summer before my final year at UofA, I interned at American Express under the Next Generation Data Management team. My project was to create a RESTful API for our language code data. Used Java with Spring MVC, as well as Maven. Wrote documentation, setup proxies, and deployed the API into production by the 8th week. Final 2 weeks were spent implementing testing suites for my API, as well as the previous APIs. ### Engineering Solutions Internship @ Raytheon Jan 2016 – Jan 2017 | Tucson, AZ Beginning my 2nd summer through my 3rd year at UofA, I interned for Raytheon Missile Systems in the IT department. I primarily tested software using virtual environments and multiple machines, ensuring that there would be no data leaks or vulnerabilities when using these tools in confidential environments. I would write scripts for engineers to install software with the configurations for a closed-lab. I had the opportunity to author internal guides, and lead presentations and workshops on tools. During my time here, I received a security clearance. ## Education ### Graduate Studies in Computer Science Stanford University Jan 2019 – Jan 2019 ### Bachelor of Engineering (B.E.) in Electrical & Computer Engineering University of Arizona Jan 2014 – Jan 2018 ## Contact & Social - LinkedIn: https://linkedin.com/in/alejandro-zaragoza --- Source: https://flows.cv/alejandrozaragoza JSON Resume: https://flows.cv/alejandrozaragoza/resume.json Last updated: 2026-03-22