Edit Customer Data (CSV/API Sources)
4 min readLast updated: February 20, 2026Customers & Contacts
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AutoLetter allows you to manually edit customer data -- but only for customers created via CSV import or the API. Data from shop integrations like Shopify or Billbee is automatically synchronized and cannot be changed directly in AutoLetter.
The editability of customer data depends on the data source:
| Source | Editable in AutoLetter? | Why? |
|---|---|---|
| CSV Import | Yes | No automatic synchronization -- AutoLetter is the only data source. |
| API | Yes | Data was manually sent via the API and has no external synchronization. |
| Shopify | No | Data is automatically synchronized from Shopify. Changes must be made in Shopify. |
| Billbee | No | Data is automatically synchronized from Billbee. Changes must be made in Billbee. |
If a customer comes from multiple sources (e.g., Shopify + CSV), only the fields that exclusively originate from the CSV or API source are editable. Fields synchronized by a shop integration remain locked.
For CSV and API customers, you can change the following contact details directly in the customer profile:
Click on the customer in the customer overview whose data you want to edit. The profile expands.
In the "Contact Details" section, you will find the editable fields. Click the edit icon or directly on a field to change it:
After making the desired changes, click "Save". The data is updated immediately.
In addition to contact details, you can also edit the addresses of CSV and API customers. AutoLetter distinguishes between different address types:
Pay special attention to the letter address. This address is used for sending your campaign letters. If the letter address is incorrect or incomplete, the letter cannot be delivered. The letter address can differ from the delivery or billing address.
The letter address is the address to which AutoLetter sends physical letters. In many cases, it is identical to the delivery address, but there are situations where a different address makes sense:
Changes to customer data affect all future letter mailings. Previously sent letters are not retroactively changed -- they were created and printed with the data valid at the time of sending.
This means:
If you need to change data for a Shopify or Billbee customer, make the change directly in the respective shop system. AutoLetter will synchronize the updated data during the next synchronization automatically.
Can I overwrite customer data from Shopify/Billbee in AutoLetter? No. Shop integrations synchronize data in one direction -- from the shop to AutoLetter. Changes must be made in the source system.
What happens if I change a customer's email? The email address is an important identification key for automatic customer merging. If you change the email, it may cause future imports to no longer correctly match the customer. Only change the email if it is truly necessary.
Will deleted fields be refilled during the next synchronization? For CSV and API customers, there is no automatic synchronization. Once deleted, data remains empty until you manually re-enter it or perform a new import.