TL;DR: Plain environment variables are [1] not safe for secrets in 2026. Coolify offers encrypted storage and Docker Build Secrets to prevent leakage; other platforms like Railway require third-party integrations; dedicated tools like [2] Infisical, [3] Vault, or cloud vaults provide audit trails and rotation. Pick Coolify’s built-in features for simple deployments, or layer Infisical for enterprise-grade management.
Coolify’s Built-In Approach
Coolify secures secrets through [4] encrypted database storage, Docker Build Secrets (using BuildKit’s --mount=type=secret), and write-only masking in the UI. Build-time secrets are isolated from runtime layers, preventing exposure in docker history or final images. This works well for single-server homelab setups but lacks audit trails and rotation.
Standalone Secrets Managers
For teams needing enterprise features, [2] Infisical (open source, self-hostable) integrates natively with Docker, Kubernetes, and GitHub Actions. [3] HashiCorp Vault is the mature reference but demands significant operational overhead; [3] OpenBao offers the Vault experience under true open licensing. Cloud-only tools like Doppler work for SaaS-only teams.
Other PaaS Platforms
[5] Dokku lacks encrypted storage and role-based access entirely. [5] Railway supports environment variables but [6] requires third-party tools (Doppler, etc.) for scale. Heroku is in [7] maintenance mode with no new features.
2026 Best Practice
[1] Treat secrets (API keys, passwords, tokens) as managed resources: store in a secrets manager with encryption, access control, and audit trails. Use environment variables only for non-sensitive config (app settings, hostnames, feature flags). For homelabs, Coolify’s Docker Build Secrets + encrypted storage suffices; for multi-team or compliance-driven setups, layer Infisical or Vault on top.