Write modes

When Data Fetcher runs your request, it transforms the API response into tabular data (fields and records) and writes it to your output view. You can control how this data is written using Write Mode settings.

Choose Your Write Mode

• Append - Add new records without changing existing ones.

• Update - Modify existing records and optionally add new ones.

How to set the write mode

1. Navigate to the request screen in Data Fetcher.

2. Scroll down to the bottom and click to open the Advanced settings.

3. Under Write Mode, select your preferred option.

Append mode

Append mode adds new records to your table without modifying existing data. This is perfect for tracking data over time, like daily sales reports or periodic updates.

Example scenario: You're tracking item sales and want to see how numbers change daily.

Your current table:

Item Id	Item name	Units sold
229	Orange Hat	5
107	Purple Skirt	10

Today's API response:

Item Id	Item name	Units sold
692	Blue T-Shirt	7
229	Orange Hat	10
107	Purple Skirt	17

After running with Append mode:

Item Id	Item name	Units sold
229	Orange Hat	5
107	Purple Skirt	10
692	Blue T-Shirt	7
229	Orange Hat	10
107	Purple Skirt	17

With a "Created time" field in Airtable, you can track how units sold changes for each item over time.

Update mode

Update mode refreshes existing records with new data. Any additional records from the API response can be created as new records (this behavior is optional).

Using the same example data from above, after running with Update mode:

Item Id	Item name	Units sold
692	Blue T-Shirt	7
229	Orange Hat	10
107	Purple Skirt	17

Important: Matching Records Correctly

In the example above, there's a problem. The first record that was originally "Orange Hat" is now "Blue T-Shirt," which could break any links or comments associated with that record.

Solution: Set an Update Based on Field to match records properly.

To avoid mismatched updates:

1. In Advanced Settings, find Update Based on Field(s)

2. Choose a unique identifier like "Item ID"

With "Item ID" as the matching field, records update correctly:

Item Id	Item name	Units sold
229	Orange Hat	10
107	Purple Skirt	17
692	Blue T-Shirt	7

Pro tip: Use an output view without Airtable filters to ensure Data Fetcher can find all matching records. Filtered views may cause duplicate records if matches are hidden.

Additional update options

Create leftover records

By default, any new records in the API response are added to your table. To change this:

1. Open Advanced Settings

2. Toggle Create records leftover after update on or off

Delete missing records

Remove records from your table that no longer appear in the API response. This is useful when the source application has deleted data.

1. Open Advanced Settings

2. Toggle Delete records not found in the API response on or off

Important: This only affects records visible in your output view. Use a view without filters to ensure all records are considered for deletion.