How Google Cloud KMS and HashiCorp Vault differ on scope, key custody, deployment and cost.
| Google Cloud KMS | HashiCorp Vault | |
|---|---|---|
| Type | Cloud KMS | Secrets platform |
| Scope | Encryption keys | Secrets, keys, PKI, dynamic credentials |
| Deployment | SaaS (GCP) | Self-hosted + HCP |
| Key custody | HSM tier FIPS 140-2 Level 3; External Key Manager for off-cloud keys | HSM auto-unseal and seal wrap in Enterprise |
| How it works | Key rings and key versions with explicit rotation, offered in software, HSM and external tiers. External Key Manager is the differentiator: the key stays in your own system and Google calls out to it, so the cloud can be denied access by design rather than by policy. | A secrets engine rather than a key store: it issues short-lived database credentials, cloud tokens and certificates on demand, so secrets expire instead of sitting in a config file. Transit lets it act as an encryption service too. Powerful, and heavy to run properly. |
| Pricing* | Metered per key version + operations | Community free (BUSL); HCP by quote |
| Free tier | No | Yes |
| Licence | — | BUSL-1.1 — not OSI-approved |
| Best for | GCP workloads and hold-your-own-key rules | Dynamic, short-lived credentials at scale |
Choose Google Cloud KMS for gcp workloads and hold-your-own-key rules. Choose HashiCorp Vault for dynamic, short-lived credentials at scale.
* Published list pricing (vendor pricing pages, August 2026).