Deploy Safety: Reducing customer impact from change

It’s mid 2023 and we’ve identified some opportunities to improve our reliability. Fast forward to January 2025. Customer impact hours are reduced from the peak by 90% and continuing to trend downward. We’re a year and half into the Deploy Safety Program at Slack, improving the way we deploy, uplifting our safety culture and continuing…

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[Image: An example service build graph. It shows a set of Python files building into a backend artifact and a set of TypeScript files building into a frontend artifact.]

November 6, 2025

18 min read

Build better software to build software better

@David Reed

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[Original source](https://slack.engineering/deploy-safety/)