About Experience Projects Life Writing

Mobile Engineer · Washington, DC

Building
things that
matter.

Senior engineer with 6+ years crafting high-availability financial applications. Currently exploring the intersection of mobile architecture and AI.

Sameer Gupta
Golf course at sunset
Homemade dessert

I'm Sameer — an engineer who likes to solve problems and make people laugh.

I build things for people. The kind of engineer who obsesses over the user experience just as much as the system architecture. I've spent my career in high-visibility roles — payments, reliability, the stuff that can't go down — and I like the challenge that comes with it.

When I'm not writing code, I'm on the golf course chasing a swing that'll never be perfect, skiing something a little too steep, cooking something a little too ambitious, or reading whatever I can get my hands on. I'm a curious person by nature and it shows.

Right now I'm deep in the AI space — experimenting with agentic workflows, building tools, and seeing what kind of returns I can get from these models. It's the most fun I've had engineering in years.

Education B.S. Computer Science, University of Maryland
Based in Washington, DC

Block, Inc. (Square)

Senior iOS Engineer, Checkout Platform

Aug 2022 – Feb 2026 Remote
  • Core engineer on iOS powering ~$15B GPV/month (~87% of Square POS volume) across ~835M monthly checkouts
  • Built reactive, hardware-aware checkout flows across NFC, EMV chip, magnetic swipe, Tap to Pay on iPhone, and Bitcoin, dynamically responding to offline mode and card reader state, helping reduce average payment processing time by 19%
  • Architected offline-first data persistence using Core Data with encryption key migration and sign-out gating, reducing unrecoverable failures from ~50/day to near-zero and supporting default-on offline payments for ~4M sellers
  • Enabled the final supported region on the iOS payments rail by navigating foreign payment regulations, region-specific card types, PIN verification modes, native refund flows, and payment retry logic, helping drive Orders API adoption from 28% to 96% across 8.8B checkouts

SAP SuccessFactors

iOS Engineer

Nov 2019 – Aug 2022 Reston, VA
  • Built reusable Swift data models and networking layers for a global enterprise HR mobile app; developed unit, UI, and integration test suites to improve release stability
  • Optimized data handling, threading, and memory management across complex workflows; delivered multi-release roadmaps in cross-functional Agile teams
  • Collaborated with backend and product teams on multi-release feature roadmaps, contributing to performance improvements and reduced regression risk across major releases

The things that keep me balanced outside of code.