AI product teams are skipping critical eval steps, Shopify saw 68% cost savings

AI product teams are skipping critical eval steps, Shopify saw 68% cost savings

Sep 22, 2026
Lenny's Newsletter AI SprinklerAS Gtm_strategy

The Gist

  • Shopify used evals to build an AI workflow 2.2x faster and 68% cheaper than frontier models
  • Most teams skip critical eval steps and automate the wrong metrics
  • Hamel and Shreya offer a free plugin for automated eval heavy lifting
Key Quotes

If there’s one thing we can teach product people, it’s that writing evals is now probably the most important thing.

Evals are emerging as the real moat for AI startups.

Key Insights
  • Most AI product teams skip the critical error discovery phase in evaluations, leading to measuring the wrong metrics.
  • Error discovery is the eval equivalent of product discovery, revealing which AI failures are worth measuring.
  • Shopify achieved 68% cost savings and 2.2x faster performance by using evals to guide AI workflow development.
  • Automated agents are useful for finding obvious errors but less reliable for failures requiring product judgment.
  • Evals help teams ship AI products faster by automatically checking if the product still works as intended.
  • Investing in evals can compound advantages over time by turning production errors into additional test cases.
Actionable Takeaways
  • Prioritize error discovery in AI product evaluations to identify critical failures worth measuring.
  • Use a hybrid approach combining human judgment and automated agents for effective error discovery.
  • Invest in evals to systematically improve AI products and compound advantages over time.
  • Generate synthetic data for initial testing if real user traces are unavailable, but prioritize real user data.
Data Points
  • 68% (Cost savings achieved by Shopify using evals to guide AI workflow development.)
  • 2.2x (Performance improvement in Shopify’s AI workflow builder compared to the frontier-model system it replaced.)
  • 41% (Cost reduction achieved by Cursor through Auto Balance routing performance guided by evals.)
  • 83% (Precision increase in Ramp’s on-device models for matching transactions in receipt photos after investing in evals.)

RevBots.ai View:

GTM teams bolting on AI features without proper evaluation systems are leaving cost savings and speed gains on the table.