AARON TAYLOR HAMMER

Square / Block, Stamford, CT — Remote

• Pitched and created the initial fullstack architecture for the Block Checkout Platform to unify all checkouts totaling $35 billion in yearly GPV spanning 8 teams across Cash App and Square.
• Ranked #1 in Cursor AI token usage while ensuring high-quality output through rigorous code reviews and precise model selection for specific tasks.
• Created, led a team of 3, and planned the frontend for Order with Google and Google Business Profile syncing for all Square and Cash App sellers, with our integration driving 24% of all online profile traffic.
• Led a team of 6 engineers to rapidly prototype Square's agentic AI commerce capabilities for Vercel's V0 team and Square leadership, proving out viability of the platform.
• With a team of 2 other engineers, brought Square's ecommerce checkouts into EAA accessibility compliance before regulatory deadlines.

Square / Block, Denver, CO — Remote

• Led several projects and owned the frontend for Square Payment Links on a 9-person team using Golang, PHP, TypeScript, and Vue — managing over $4B in processing volume, growing 62% YoY for 2024.
• Rebuilt Square Payment Links' tipping feature to let over 1 million sellers customize tip percentages, support local currencies, and provide more localized tipping defaults.
• Drove a reliability code red: created and owned our observability stack in Datadog and led a 90-day plan to bring all SLOs from failing to 99.995%.
• Led the migration of Payment Links services from on-prem to AWS infrastructure using Terraform.
• On my own initiative, investigated bot traffic inflating Datadog RUM costs and filtered them out, reducing spend by $28k/month — 10% of my org's bill and 2% of Block's total usage.
• Created the buyer-side frontend for Square's restaurant QR code checkout experience and unlocked over $70M in processing volume for Square Payment Links MoM.

Formerly Rally Health — Optum Digital / UnitedHealth Group, Denver, CO — Remote

• Contributed with an 8-person Scrum team to a React frontend and Scala microservice backend for the UHC healthcare client dashboard, accessed by 50M+ customers worldwide.
• Led rapid frontend implementation of an SSO redirect on myUHC enabling 26M+ customers to receive free COVID-19 tests within a week to meet federal mandates.
• Drove a performance initiative reducing the max bundle from 1.62MB to 495KB and cutting FCP by 0.4s via lazy-loading, bundle-splitting, and concurrent rendering.
• Migrated the myUHC client dashboard from AngularJS to ReactJS with a dedicated team.

Clearview Social, Denver, CO — Remote

• Modeled and built AWS infrastructure for a scalable serverless image caching API that returns images in specified sizes and formats while caching alternatives, cutting image transfer size by 50%+.