How Zapier runs isolated tasks on AWS Lambda and upgrades functions at scale

Zapier snaps each customer Zap into its own AWS Lambda, cradled inside lean Firecracker microVMs. It wrangles 100k+ functions under an EKS control plane and inventory DB. When runtimes retire, Zapier swings into action: a set of Terraform modules paired with a custom Lambda canary tool. Traffic trickles in. Rollback fires the moment things falter. Cleanup purges the old. Boom—95% fewer deprecated runtimes.

Infra shift: Canary-fueled upgrades and IaC morph serverless into a self-healing machine.