> ## Documentation Index
> Fetch the complete documentation index at: https://bakefile.wisl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Environments

> EnvBakebook and environment mixins give each environment (dev, staging, prod) its own typed bakebook, selected by the ENV variable.

For projects with multiple environments (dev, staging, prod), use environment mixins:

```python theme={"theme":{"light":"github-light","dark":"github-dark"}}
from bakelib.environ import (
    BaseEnv,
    DevEnvMixin,
    EnvBakebook,
    ProdEnvMixin,
    StagingEnvMixin,
    get_bakebook,
)


# Compose env mixins with EnvBakebook
class DevBakebook(DevEnvMixin, EnvBakebook[BaseEnv]): ...


class StagingBakebook(StagingEnvMixin, EnvBakebook[BaseEnv]): ...


class ProdBakebook(ProdEnvMixin, EnvBakebook[BaseEnv]): ...


bakebook_dev = DevBakebook()
bakebook_staging = StagingBakebook()
bakebook_prod = ProdBakebook()

# Select bakebook based on ENV environment variable
bakebook = get_bakebook([bakebook_dev, bakebook_staging, bakebook_prod])
```

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
ENV=prod bake deploy    # Uses prod bakebook
ENV=dev bake deploy     # Uses dev bakebook
bake deploy             # Defaults to dev (lowest priority)
```

## Custom environments

Create custom environments by inheriting from `BaseEnv`:

```python theme={"theme":{"light":"github-light","dark":"github-dark"}}
from bakelib.environ import BaseEnv, EnvBakebook


class MyEnv(BaseEnv):
    ENV_PRIORITY_ORDER = ("dev", "sit", "qa", "uat", "prod")


class MyEnvBakebook(EnvBakebook[MyEnv]):
    env: MyEnv = MyEnv("dev")
```

Each environment bakebook is a full [Bakebook](/concepts/bakebook), so tasks and settings can differ per environment through plain inheritance.