Etsy's 2012 blameless postmortems turn failure review into a ritual the industry copies

Etsy's site had real outages and accidents, and the traditional reaction — find who made the error and make an example of them — pushed honest accounts underground and fixed nothing.

Treat accidents as learning events, not crimes: hold blameless postmortems where engineers can give honest accounts, and fix the system instead of the person.

Allspaw published the practice on Code as Craft in May 2012, attacking the 'Bad Apple theory' and calling human error a symptom of system conditions; reviews ask what allowed the accident, and in 2017 Etsy open-sourced a facilitation guide for running such debriefs.

The post helped make 'blameless postmortem' a standard of engineering culture: the term now appears in incident-response doctrine across the industry, and Etsy's guide is still cited by teams learning to run reviews.

In May 2012 John Allspaw, then leading Etsy's technical operations, published 'Blameless PostMortems and a Just Culture' on the company's engineering blog. The post rejected the 'Bad Apple theory' — the idea that the way to eliminate error is to eliminate the people who make it — and argued that 'human error' is a symptom, not a root cause.

The practice was concrete: after an outage or accident, Etsy reviewed what happened without assigning blame, so the engineers whose actions contributed could give a detailed, honest account. Allspaw linked the approach to 'just culture', a principle borrowed from fields like healthcare and aviation where punishing honest reporting makes systems less safe.

In 2017 Etsy went further and open-sourced a Debriefing Facilitation Guide on GitHub, describing the postmortem as 'first and foremost a learning opportunity, not a fixing one' and explaining how to facilitate the debrief itself. The 2012 post became one of the most cited work ideas in engineering, and 'blameless postmortem' entered the vocabulary of teams far beyond Etsy.

Blame makes people hide what they did, so the real causes never surface

Human error is a symptom of system conditions, so fixing the person fixes nothing

Honest accounts turn one team's failure into everyone's lesson

A public guide made the practice teachable instead of a personality trait

Blaming individuals makes incidents harder to learn from: when people can describe their actions honestly, the real system flaws surface — and those are what can be fixed.

Etsy operationalized the idea over the following years and published its facilitation guide openly in 2017 (the repository was archived in 2025). 'Blameless postmortem' became a tenet of incident-response culture across the industry, including in Google's SRE doctrine, and Allspaw's post is still cited as the canonical statement of the idea.