Stephen Geller

Software Engineer

Block (Cash App) May 2022 - November 2025

Architecting and delivering scalable backend solutions on the Support Product team that enhance customer support experiences globally. Leading end-to-end feature development focusing on customer identity verification, support automation, and operational excellence.

• Improved support efficiency for millions of customers — Led development of Tap to Confirm, a customer identity verification system with in-app confirmation flows
• Scaled verification to millions of interactions — Architected PIN-based verification, biometric authentication, and fallback mechanisms
• Drove org-wide adoption of SLO frameworks — Created deployment drift monitors adopted across multiple teams, improving system reliability
• Eliminated legacy dependencies — Migrated customer data systems to CAPS, improving data consistency
• Accelerated advocate workflows — Developed tools for PII verification, case management, and customer search
• Grew team capabilities — Mentored engineers through code reviews, pair programming, and technical guidance
• Improved system resilience — Led incident response and post-mortem processes

Software Engineer

Cogent / Redbubble December 2021 - May 2022

Consultant engineer at Redbubble on the Shop Experience team, focusing on frontend development and infrastructure improvements.

• Enhanced storefront experience — Built new front-end components for Redbubble landing pages
• Unified content delivery — Integrated frontend through a backend-for-frontend to Contentful
• Modernised tech stack — Upgraded libraries and Node versions across multiple applications

Software Engineer

The Guardian August 2019 - August 2021

Focused on quality engineering and developer experience improvements across the Guardian's digital department.

• Centralised observability across teams — Built metrics platform using Grafana, Elasticsearch and AWS CloudWatch
• Simplified AWS infrastructure management — Created custom Guardian CDK library
• Reduced production incidents — Built Cypress integration test service to monitor key user journeys
• Improved team communication — Created chatbots integrating PagerDuty and GitHub events to Google Chat
• Fostered diversity in tech — Established mentorship program between the Guardian and Coding Black Females

DevOps Engineer

Lush Digital May 2019 - August 2019

Worked with Kubernetes and monitoring infrastructure using Prometheus and Alertmanager.

Software Developer

Unruly Media December 2017 - May 2019

Worked in the Shared Infrastructure team, following XP and Agile practices throughout infrastructure development.

• Maintained platform reliability — Managed shared infrastructure systems across the organisation
• Reduced manual toil — Created tested, reactive scripts to automate operations
• Upskilled engineering teams — Led code dojos and workshops to share knowledge