# Creating Configuration File

The configuration file is where you store all the devices informatiom. To start flowchem API, configuration file is the only requirment. It is built in an easily editable `.toml` format.
For more details about this file format, please visit [TOML](https://toml.io/en/).


First of all, create a toml file save it as TOML formate. For instance, create a file call 'flowchem_config.toml'
(or after getting it from the [examples folder](https://github.com/cambiegroup/flowchem/tree/main/examples))

After creating the file, add all devices setting to the configuration file. For instance:
```toml
[device.test-device]
type = "FakeDevice"
```
In this file, the term `device` indicates that the device is implemented in the package. The term `test-device` is the
device name chosen by the user, and `FakeDevice` is the device type corresponding to the class implemented in the
package source code. Depending on the type of device specified in the file, additional attributes may be required.

All necessary attributes for each device type can be found in the
[Device configuration guides](../reference/devices/supported_devices.md).

More detailed explnation of flowchem Configuration file can be found in [flowchem Configuration File:
Simple, Flexible, and User-Friendly](../explanation/conf_file.md).


## Running flowchem

Run the `flowchem` command in the terminal followed by the name of the configuration file.

```shell
flowchem flowchem_config.toml
```
```{important}
Please note that when running this command in the terminal, the file must be in the same folder as the terminal. If the
 terminal is in a different folder, please add the configuration address file after "flowchem" or change the current
 folder in the terminal.
```

In your terminal, you will see some debug information, ending with a line like this one:
```shell
INFO:     Uvicorn running on http://0.0.0.0:8000 (Press CTRL+C to quit)
```

This means that the flowchem server has been started correctly.
You can visit [http://127.0.0.1:8000](http://127.0.0.1:8000) to see a list of commands available for your test device.

```{note}
The device name is used as first subdirectory in the URL of the commands relative to this device.
For example, in this case, the commands relative to our test device will be available under `http://localhost:8000/example1/`.
```
```{note}
For every request sent to the flowchem server, you will see some diagnostic output in the terminal.
While you can normally ignore this output, it can provide useful information in case of errors.
```

If the user want to run a example file to operate a simulated device for educational purposes without
requiring any connected device, simply execute:

```shell
flowchem example
```

This command will run flowchem directly with a configuration file in the
[package directory](../../../examples/FakeDevice_configuration.toml).

## Device autoconfiguration

To be able to write a configuration file, you need to know the type of device you want to connect to and some connection
parameters.

Flowchem is capable of auto-detecting some devices and instrument, and to generate a valid configuration stub for them.
To find any device already connected to the PC where flowchem is installed, run the autodiscover tool:
```shell
flowchem-autodiscover
```
And reply to the prompts.
If any device that supports autodiscovery is found, a `flowchem_config.toml` file will be created. See more details
in [tools](../tools.md).