Exporting legacy custom objects using the data export tool

Use the custom object data export tool to download your legacy custom object records and legacy relationship records from Admin Center as CSV files packaged in a ZIP archive. This export is intended to be used as the “extract” step of your migration workflow. You can transform the CSV data as needed and then load it into the new custom objects experience using the Custom Objects APIs or the Admin Center data importer.

Using the export tool

Launch the export tool from Admin Center:

1. In Admin Center, click Objects and rules in the sidebar, then select Custom objects > Objects.

2. Click Export Tool in the banner.

3. Review the list of legacy objects and relationships shown in the export window.

4. Click Export next to the object or relationship type you want to export.

   The export runs as a background job. You don't need to stay on this page while it runs.

5. When the job completes, click Download ZIP to download the exported files.

Understanding the export file format

Each export is delivered as a ZIP file. The filename depends on what you export:

• Object exports: resources_{objectkey}_export.zip
• Relationship exports: relationships_{relationship_type_key}_export.zip

Exports are split into multiple CSV files to keep large datasets manageable and compatible with tools like Microsoft Excel and Google Sheets.

• Each CSV file contains up to 20,000 records
• Datasets larger than 20,000 records are automatically split into batches within the same ZIP file

For example, a dataset with 200,000 records is split into multiple files in the ZIP archive, with filenames like:

• Object records: {object_key}_batch_1.csv, {object_key}_batch_2.csv, and so on
• Relationship records: {relationship_type_key}_batch_1.csv, {relationship_type_key}_batch_2.csv, and so on

The columns in your exported files depend on the type of data being exported. Relationship records always have the same three columns, but object records have columns for the standard fields and all custom fields defined in the legacy custom object's schema.

Object records CSV columns

Column	Description
id	Unique system id for the legacy record
external_id	Your custom identifier (if set)
updated_at	Timestamp of the last update
{field names}	One column per custom field defined in the legacy schema

Note: If a legacy field is a complex type (for example, an array or object field containing JSON), the export tool writes the entire value into one CSV column as a string to preserve data integrity.

Relationship records CSV columns

Column	Description
id	Unique relationship record id
source_id	id of the source legacy object record
target_id	id of the target legacy object record

Example output

The following examples show what exported objects and relationship records look like in CSV format.

Example: Contract records

id	external_id	updated_at	contract_active	contract_amount	contract_end_date	contract_id	contract_type
5ba05309-0606-11f1-adb8-c39cdaefd342		2026-02-09 22:26:20.0	TRUE	200	2026-12-12	Contract #1	Individual
5bb4c56b-0606-11f1-adb8-7b1d048effc5		2026-02-09 22:26:20.0	TRUE	300	2026-12-13	Contract #2	Combined
5bc58e4b-0606-11f1-95c1-df928a0ddb00		2026-02-09 22:26:20.0	TRUE	400	2026-12-14	Contract #3	Combined
5be216fd-0606-11f1-95c1-696b5c2e0f03		2026-02-09 22:26:21.0	TRUE	500	2026-12-15	Contract #4	Combined
5bf81001-0606-11f1-aede-372d005a3222		2026-02-09 22:26:21.0	TRUE	600	2026-12-16	Contract #5	Individual
ad5a42a5-0606-11f1-b67a-0bc5d229d023		2026-02-09 22:28:37.0	TRUE	700	2026-12-17	Contract #6	Individual

Example: Vehicle record with a complex field

id	external_id	updated_at	make	model	specs
d6dbec423a		2026-01-27	Honda	Civic	{"engine":"1.5L Turbo","mpg":33.5}

Example: Owner-to-car relationship record

id	source_id	target_id
0afb9bb153	2e520bfg23	2c99866h98