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Spotify Doubled Merged Code Changes to 17,000 a Month With AI. Verification Became the Bottleneck.
Quality work rose to 31% of merges, yet one dependency upgrade that passed every check still hurt users.
Spotify has never said which library broke. Some time in 2026 its Fleet Management system pushed out an automated dependency upgrade, and it went green on every check the company had before falling over in production in front of real users. The service, the symptom, the time it took to revert: none of that is in the post. This is the war story Spotify only half tells.
After merges doubled, a bad upgrade slipped past every check just as spare capacity tightened. In August 2025 Spotify merged roughly 8,100 code changes. By August 2026 it was about 17,000 a month, and in between came the failed upgrade and a May incident after which Spotify doubled its reserved edge capacity. On 16 September Tyson Singer, head of technology and platforms, published the account, gave the upgrade one sentence and named the wider cause: “that increased automation also creates new failure modes”. Figures here are Spotify’s own unless I credit InfoQ’s 12 October write-up, and nobody outside has audited them.
“AI increased the capacity to produce change. The next constraint became…
