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SF-0231 · Concept · Easy

In which file format can we save salesforce mapping?

✓ Verified by Vikas Singhal · Last reviewed 5/17/2026 · Updated for Spring '26

Data Loader saves field-mapping files in the .sdl (Salesforce Data Loader) format. It’s a plain-text file you can open in any editor.

What an .sdl file looks like

#Mapping values
#Mon May 17 10:23:18 IST 2026
CompanyName=Name
Phone=Phone
WebsiteURL=Website
LegacyId=Legacy_Id__c
BillingCity=BillingCity
BillingCountry=BillingCountry

Two things to notice:

  • One mapping per line. The format is CSV_column=Salesforce_API_name.
  • Header comments at the top record when the file was saved.

You can hand-edit it in Notepad or VS Code if you need to tweak a mapping without re-opening Data Loader.

How to save a mapping

While in a Data Loader job:

  1. Reach the Mappings dialog (after you’ve selected the CSV).
  2. Drag column headers onto the matching Salesforce fields, or click Auto-Match Fields to Columns.
  3. Click Save Mapping.
  4. Choose a path and filename like account-insert.sdl.

How to load a saved mapping

In the same dialog, click Choose Existing Map → pick your .sdl file. Data Loader applies the mappings to the currently selected CSV.

Why save mappings

  • Reuse. A monthly Account refresh from your billing system uses the same column → field mapping every time.
  • Consistency. Multiple admins running the same job get identical mappings, so the output is reproducible.
  • Version control. Check the .sdl into Git alongside the script that generates the CSV and runs process.bat. The whole ETL job becomes a tracked artifact.
  • CLI use. Data Loader’s command-line runner (process.bat / process.sh) requires .sdl mapping files referenced from its config XML. Scheduled jobs are impossible without them.
  • Onboarding. New team members can see exactly how a load is wired without rebuilding the mapping from scratch.

Trap

When you change the source CSV’s column names, the .sdl file stops matching and rows fail silently with missing fields. Either keep column names stable, or update the .sdl whenever the CSV header changes. Diff-reviewing the .sdl before each run is a tiny investment that catches a lot of pain.

Verified against: Data Loader Guide — Creating and Editing the Field Mapping File, Metadata API Developer Guide. Last reviewed 2026-05-17 for Spring ‘26 release.