Doppler

Doppler is a secrets management platform built for developer experience: it stores API keys, database URLs, tokens, and certificates in a single system of record and delivers them to applications at runtime. Projects contain environments, each with a root config and branch configs that inherit from it, replacing scattered .env files with one source of truth.

The Doppler CLI injects secrets as environment variables (doppler run), with integrations across GitHub Actions, Vercel, Kubernetes, and other infrastructure, plus secret referencing, dynamic secrets, automatic rotation, and audit logging for SOC 2 and ISO compliance. A 2026 product push explicitly targets AI agents and MCP servers as secret consumers, with cloud or on-prem deployment. Doppler is proprietary SaaS with no self-hosted option, which is the main trade-off versus open-source alternatives; reviewers also note it lacks agent-specific guardrails against secrets leaking into agent chat transcripts.

Sign up at doppler.com, install the CLI, then wrap your start command (doppler run -- npm start) to inject secrets at runtime. Sync integrations configured from the dashboard.