What is HashiCorp Vault?

HashiCorp Vault is a tool that safely stores and manages secret information like passwords, API keys, and certificates. It lets applications and people retrieve those secrets when needed, without exposing them to the world.

Let's break it down

  • Tool: a piece of software you can install and run.
  • Safely stores: keeps data in a locked box that only authorized users can open.
  • Secret information: things you don’t want everyone to see, such as passwords, tokens, encryption keys, or certificates.
  • Passwords, API keys, certificates: examples of secrets that let programs talk to each other or prove identity.
  • Applications and people: both computer programs and human operators can ask Vault for a secret.
  • Retrieve… without exposing: Vault gives the secret only to the requester, so it never gets written in plain text on disks or logs.

Why does it matter?

Because leaking a single password or key can let attackers break into systems, Vault reduces that risk by centralizing secrets, controlling who can see them, and automatically rotating them. It helps keep your software and data safe while making secret management easier for developers.

Where is it used?

  • A cloud-native company stores database credentials in Vault and lets its microservices fetch them at startup, so credentials never live in code repositories.
  • An e-commerce site uses Vault to generate short-lived API tokens for payment gateways, limiting the damage if a token is stolen.
  • A DevOps team stores SSH private keys in Vault and grants temporary access to engineers during incident response, then revokes it automatically.
  • A fintech firm encrypts sensitive customer data and stores the encryption keys in Vault, ensuring only authorized services can decrypt the data.

Good things about it

  • Centralized secret storage eliminates scattered passwords in config files.
  • Fine-grained access control lets you decide exactly who or what can read each secret.
  • Automatic secret rotation reduces the window of exposure if a secret is compromised.
  • Audit logs record every secret request, helping with compliance and investigations.
  • Supports many secret types (key/value, dynamic credentials, certificates) and integrates with major cloud providers.

Not-so-good things

  • Setup and configuration can be complex for teams new to secret management.
  • Running Vault in high-availability mode requires extra infrastructure and careful planning.
  • Performance may become a bottleneck if thousands of services request secrets simultaneously without proper caching.
  • Learning the policy language and managing policies at scale can be challenging.