A list is a file containing identifiers for existing contacts that can be imported into your account and targeted immediately. **Each identifier must be associated with an existing contact in your Simon account.**
Is this the right CSV upload method for your use case?
Be sure to read through the use cases below before moving on to upload.
# Use Cases
There are a few ways to upload data into Simon via a .csv and it’s important to know the differences between them so you can quickly get what you need out of the platform.
**My CSV has a list of emails with other fields that I would like to use for segmentation and/or personalization.**
The CSV can be uploaded as a [contact dataset](🔗) with the option to source the data from an upload instead of a database.
The additional fields will need to be named and set for use as condition and/or content (segmentation and/or personalization).
This option will require a full refresh before it becomes available for use.
**My CSV has a list of emails with no other fields and I would like to use it in segmentation alongside existing fields or segments (e.g. suppression).**
When [creating a dataset](🔗), choose **Contact Segment**.
This will require a refresh to use.
When in the [segment](🔗) builder, search for _customer segment_ and your new dataset will be in the drop down that appears.
This is best used for suppression groups.
**My CSV has a list of emails with no other fields and I would like to use it in segmentation but do not need to mix it with other criteria.**
The quickest way to target an audience from a CSV is the [list upload feature](🔗). This allows allows you to upload a list of emails and make them available for segmentation in just a couple of minutes, instead of having to wait for a refresh. However, it cannot be mixed with any non list-upload segmentation criteria so you will only be able to use the CSV as your audience for taking actions.
Note: Emails must be present in Simon already.
**My CSV does not have a list of contact information.**
A [lookup table](🔗) is likely the route we will go here. Contact your account manager for alternative workflows.
Lists for immediate use
You can create a [upload list](🔗) to immediately create a flow or journey with a list of contacts, however these contacts will not be saved for future use. CSV is the way to go if you're planning on using these contacts a lot.
## Dos and don’ts
**If you're uploading a CSV with more columns than just email address, ensure the additional fields aren’t already in Simon, and/or the fields that will actually be used.**
CSVs are commonly uploaded with extra fields which then become new properties for all contacts in Simon. For this reason we recommend that CSV uploads contain no columns other than email unless it’s needed for the campaign and can’t be pulled into Simon from a database
**How to find a .csv uploaded as a Contact Segment**
Contact segment CSV uploads can be found in the segment builder under **Customer Segment**. Use the search box to find your uploaded dataset.
## File format
A list should be uploaded as a file with a ".csv" extension. The file should contain a single column with **no header** and only identifier.
Usage and limitations
Lists may be used as an **include** condition with the definition of a segment, and cannot be used as suppression. These segments can be used to message audiences using One-Time flows only.
A segment may only use **one** List as a condition in the definition. Additionally, a segment that references a List in its conditions may not be used as a base segment or referenced by another Segment.
# Upload a list
From the left navigation, expand Datasets then click **Datasets**.
Click _+ Create Dataset_.
Select _Upload Lists_, then click _Next_.
Enter a **name** for the list. The source will automatically be selected as "File Upload" and the identifier will be your default identifier (often email address). Click _Start_.
Click **Choose CSV** and then click **Upload** to import your list.
**Validate** and **commit** your list.
Your list is now available; to us it, create a segment and select your list name under the **Lists** section of the condition. Please note that it may take up to a few minutes for your list to be available in the segment builder in the case of very large files.