How AWS KMS and HashiCorp Vault differ on scope, key custody, deployment and cost.
| AWS KMS | HashiCorp Vault | |
|---|---|---|
| Type | Cloud KMS | Secrets platform |
| Scope | Encryption keys | Secrets, keys, PKI, dynamic credentials |
| Deployment | SaaS (AWS) | Self-hosted + HCP |
| Key custody | FIPS 140-3 Level 3 validated HSMs | HSM auto-unseal and seal wrap in Enterprise |
| How it works | Keys never leave the service — you call it to encrypt and decrypt rather than fetching key material. Envelope encryption is the normal pattern: KMS protects a data key, the data key protects your data. Every AWS service integrates natively, which is most of the value. | 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* | $1/key/mo + $0.03 per 10k requests | Community free (BUSL); HCP by quote |
| Free tier | Yes | Yes |
| Licence | — | BUSL-1.1 — not OSI-approved |
| Best for | Anything already running on AWS | Dynamic, short-lived credentials at scale |
Choose AWS KMS for anything already running on aws. Choose HashiCorp Vault for dynamic, short-lived credentials at scale.
* Published list pricing (vendor pricing pages, August 2026).