Stack Spend

Author

Andrew Day

AI & software engineering leader — 18 years in enterprise banking technology, ML, and LLM applications.

AI & Software Engineering Leader103 articlesLinkedIn

About Andrew Day

Andrew Day is a senior technology leader with 18 years of experience in software engineering, enterprise banking technology, AI, and data engineering.

For the past 8 years he has worked in AI-driven startups, leading the development of machine learning systems and large language model applications in production.

He has led cross-functional engineering teams across Europe, North America, and Asia, and writes here about the cost side of running a modern AI and cloud stack: forecasting, anomaly detection, model selection, and the operating process that keeps spend predictable.

Writes about

  • Cloud Cost Management
  • FinOps
  • Large Language Models
  • AI Cost Optimization
  • Software Architecture
  • Data Engineering
  • Enterprise Banking Technology

Articles by Andrew Day

GuidesOctober 6, 2026

The Best Coding Models in October 2026 — and How to Route Them

Claude Opus 5.5 and Sonnet 5.5, GPT-6 Astra and GPT-6.1 Sol, Gemini 3.8 Flash and Grok 4.7 all shipped since our August issue. A research-grounded October 2026 playbook for engineering leads: which model for which job, what it costs, and why the combined bill is now the hard part.

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GuidesMarch 6, 2026

Cloud and AI Budget Health Check

Score your current budget process and identify the next 30 days of improvements. A practical maturity scorecard for teams that want confidence, not perfection.

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InsightsFebruary 11, 2026

Board-Ready Infra Reporting for CTOs

Your board doesn't want dashboards or spreadsheets. They want a clear narrative about infrastructure spend — are we on track, and where is the money going? Here's how to build that report.

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Andrew Day — AI & Software Engineering Leader at StackSpend