TLDR; Vendor lock-in inflates multi-cloud costs by 20–30% through proprietary APIs, egress fees, and retraining overhead. Standardize on Kubernetes, Terraform, and open data formats (Parquet, PostgreSQL) for portability. Use abstraction layers like Crossplane and service meshes to isolate cloud-specific code. Plan exit strategies from day one with documented data portability and tested failover runbooks. EU teams benefit from portability when meeting GDPR and EU Data Act requirements. Cloud portability is no longer a luxury for European startups and mid-market CTOs watching budgets tighten. Avoiding vendor lock-in cost optimization means architecting workloads so you can move between AWS, Azure, GCP, OVHcloud, or Scaleway without rewriting half your stack.…