> For the complete documentation index, see [llms.txt](https://docs.baas.sh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.baas.sh/baas-cli/authentication.md).
# Authentication
`baas login` authenticates you with BaaS through your browser. Once you're logged in, every other command uses your session automatically.
## Log in
```bash
baas login
# Opening your browser to log in to BaaS...
# ✔ Logged in as you@example.com
```
Your browser opens to authenticate. On success, your tokens are saved to `~/.baas/credentials.json` and refreshed automatically before they expire, so you won't need to log in again.
If you're already logged in, the CLI asks before re-authenticating:
```bash
baas login
# ? Already logged in as you@example.com. Log in again? (y/N)
```
Answer `y` to re-authenticate, or `N` to keep your current session.
## Log out
```bash
baas logout
```
Revokes the CLI session on the server and removes your local credentials.
{% hint style="info" %}
**Where your credentials live:** `~/.baas/credentials.json`, with `0600` permissions (readable only by you). It holds your access and refresh tokens; **no wallet private key is ever stored** (relayer deployments sign server-side).
{% endhint %}
Under the hood (OAuth 2.0 + PKCE)
`baas login` runs the standard browser-based OAuth 2.0 Authorization Code flow with PKCE. The CLI starts a short-lived local server on `127.0.0.1`, opens your browser to authorize, receives the callback (validated with a `state` parameter), and exchanges the code for tokens. You don't need to know any of this to use the CLI.
## Next
* [Projects](/baas-cli/projects.md) — list your projects and choose the active one.
* [Troubleshooting](broken://pages/2QIKRDlpLdXoaDPZhTBj) — fixes for `Not logged in` and `Session expired`.
---
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