HashiCorp Vault vs AWS Secrets Manager: Secrets Management Comparison

Overview

HashiCorp Vault is an open-source secrets management platform with capabilities spanning dynamic secrets, PKI, encryption as a service, and identity-based authentication. AWS Secrets Manager is a fully managed AWS service for storing and rotating static secrets. Both handle secret storage, but Vault's capabilities extend far beyond what Secrets Manager offers.

The comparison is often framed as operational complexity versus managed simplicity. Vault provides dramatically more capability but requires significant investment to operate. Secrets Manager provides essential secret storage with zero operational overhead within the AWS ecosystem.

Key Technical Differences

Vault's dynamic secrets engine is its most powerful differentiator. Instead of storing long-lived credentials, Vault generates short-lived credentials on demand. For AWS IAM roles, Vault can create temporary IAM users with specific policies and TTLs. For PostgreSQL, Vault generates a new database user with a 1-hour TTL — credentials that expire before an attacker can exploit a breach. AWS Secrets Manager stores static secrets and supports rotation (via Lambda functions) but does not generate credentials dynamically.

Vault's PKI secrets engine manages a full certificate authority hierarchy. It issues X.509 certificates with configurable TTLs, enabling certificate rotation on a 24-hour cycle rather than annual renewal. This dramatically reduces the blast radius of certificate compromise. AWS has ACM (Certificate Manager) for public certificates and ACM PCA for private CAs, but these are separate services.

For Kubernetes, Vault provides both the Agent Sidecar Injector (injects secrets as files into pods via init containers) and the newer Vault Secrets Operator (syncs Vault secrets to Kubernetes Secrets). AWS Secrets Manager requires External Secrets Operator or custom SDK integration for Kubernetes workloads.

Performance & Scale

Vault in HA mode (with integrated Raft storage or Consul) can handle thousands of secret operations per second. AWS Secrets Manager is a managed service with high availability and scales automatically. For pure secret retrieval performance, both are more than adequate for most workloads.

When to Choose Each

Choose Vault for multi-cloud environments, dynamic credentials, PKI management, or when comprehensive audit logging is a compliance requirement. The operational investment is justified by capabilities that Secrets Manager cannot provide.

Choose AWS Secrets Manager for AWS-only workloads where static secret storage, automatic rotation, and native IAM integration meet requirements. Zero operational overhead is the primary advantage.

Bottom Line

Vault is the more capable platform by a wide margin; Secrets Manager wins on operational simplicity within AWS. Organizations with multi-cloud requirements or dynamic secret needs should choose Vault; AWS-only teams with simple secret storage needs should start with Secrets Manager.