# Environment Variables

The following environment variables may be used to configure pymmcore-plus globally.

*Unless noted otherwise, boolean variables can be set to `1`, `0`, `True`, or `False` (case insensitive).*

| Variable | Description | Default |
| --- | --- | --- |
| **`PYMM_DEBUG_LOG`** | Call `enableDebugLog(True)` when creating a `CMMCorePlus`. |  |
| **`PYMM_STDERR_LOG`** | Call `enableStderrLog(True)` when creating a `CMMCorePlus`. |  |
| **`PYMM_BUFFER_SIZE_MB`** | Circular buffer memory footprint in MB. | MMCore's default (250 MB) |
| **`PYMM_STRICT_INIT_CHECKS`** | Enable/disable strict initialization checks | Enabled |
| **`PYMM_PARALLEL_INIT`** | Enable/disable parallel device initialization | Enabled |
| **`PYMM_LOG_LEVEL`** | pymmcore-plus [logging](<https://pymmcore-plus.github.io/pymmcore-plus/guides/logging/index.md>) level for the console. | `'WARNING'` |
| **`PYMM_LOG_FILE`** | Logfile location. Set to `0`, `false`, `no` or `none` to disable logging to a file. | `pymmcore-plus.log` in the pymmcore-plus [log directory](<https://pymmcore-plus.github.io/pymmcore-plus/guides/logging/#customizing-logging>) |
| **`PYMM_LOG_RICH`** | Use [rich](<https://rich.readthedocs.io/>) for stderr logging (`1`, `true` or `yes`). Adds some formatting overhead ([\#449](<https://github.com/pymmcore-plus/pymmcore-plus/issues/449>)). | `"0"` (disabled) |
| **`MICROMANAGER_PATH`** | Override location of Micro-Manager directory (with device adapters) | Found automatically (see the [search order](<https://pymmcore-plus.github.io/pymmcore-plus/install/#setting-the-active-installation>)) |
| **`PYMM_SIGNALS_BACKEND`** | The event backend to use. Must be one of `'qt'`, `'psygnal'`, or `'auto'` | `auto` (Qt if a `QApplication` exists when `CMMCorePlus` is created, otherwise psygnal) |
| **`PYMM_DISABLE_IPYTHON_COMPLETIONS`** | Set to `1` to disable [Tab autocompletion for IPython](<https://pymmcore-plus.github.io/pymmcore-plus/guides/ipython_completion/index.md>) | `"0"` (enabled) |
| **`UNICORE_SEQUENCE_BUFFER_MB`** | Size of the sequence buffer used by [`UniMMCore`](<https://pymmcore-plus.github.io/pymmcore-plus/guides/unicore/index.md>) for Python cameras, in MB. | 1024 MB (250 MB on CI) |