21st CLI — find, install & generate from the terminal

The 21st CLI (npx @21st-dev/cli, bin 21st) is the command-line surface for the 21st.dev catalog. Search first, install what fits, and only hand-write UI when nothing matches. To publish your own components/themes/templates, use the 21st-registry skill; to publish a project's design as a theme, use 21st-design-sync.

Auth (do this once)

Two interchangeable credentials, both sent as the API key:

1. Login session — npx @21st-dev/cli login opens the browser and saves a token to ~/.config/21st/auth.json. Best for interactive/dev machines.
2. API key — 21st_sk_… from https://21st.dev/mcp (or https://21st.dev/settings/api-keys). Pass via --api-key <key> or the TWENTYFIRST_TOKEN / API_KEY_21ST env var. Best for CI.