Daniel Blazevski

About Daniel Blazevski

Backend engineer working in payments/fintech. I enjoy ensuring high scale, complex systems are reliable.

Experience

1. Software Engineer (L6, Tech Lead)

   Square

   Feb 2021 — Present · New York, NY, US

   20••••26] Tech lead for a 20+ engineer, cross-team, cross org initiative to migrate the Square Point of Sales app onto the Orders Platform that powers all Square sales (Q4 2024 Earnings letter: https://s29.q4cdn.com/62•••••76/files/doc_financials/2024/q4/Shareholder-Letter_Block-4Q24pdf.pdf) Improved reliability of core tier-0 endpoints (Create / Update Order / Checkout) to over 99.95% success rate across thousands of requests / second. Designed and implemented custom error classification tooling (Datadog dashboards, monitors) that became the source of truth for reliability metrics, enabling self-serve debugging and SLO-driven prioritization across teams.Enabled and contributed to root-cause analysis of aggregated error buckets, leveraging system context to guide prioritization and unblock investigations across teams. Empowered engineers to quickly identify high-leverage work and quantify the impact of code changes on system reliability.Led execution across multiple teams by defining roadmap, organizing engineers into pods, and driving high ownership and delivery velocityPresented wins in a company-wide engineering all-hands in Nov 2025.[20••••24] Led multi-quarter initiative to launch a new payment assignment service for a mission critical CRM app that manages all of Square merchants’ customer data.Prioritized stability improvements of the new service to help get to 99.99% of payments assigned within 10 seconds. Backfilled 18+ billion payments out of the legacy service while maintaining uptime.

Education

• The University of Texas at Austin

  Doctor of Philosophy (PhD), Mathematics

  2012

• University of Michigan

  Bachelor of Science (BS), Mathematics

  2007

Skills

• Project Management
• Statistics
• Machine Learning
• Mysql
• Distributed Systems
• Mpi
• Java
• Partial Differential Equations
• Data Analysis
• Nosql
• Python
• Physics
• Matlab
• Applied Mathematics
• Research
• Algorithms
• Parallel Computing
• C++
• C
• Software Engineering
• Scala
• Hadoop
• Fortran