Both Data Loader and the Data Import Wizard accept exactly one input format: CSV (Comma-Separated Values). Excel files (.xlsx), Tab-Separated (.tsv), JSON, XML, Parquet — none of them work directly. You convert to CSV first.
What “CSV” actually means in this context
A specific shape:
- First row is a header with column names.
- Each row after is one record.
- Commas separate fields.
- Double-quotes wrap any field that contains a comma, newline, or quote (the quote is escaped by doubling:
""). - One file = one object (for both tools).
A clean example:
Id,Name,Industry,AnnualRevenue
0015g00000ABCDE,"Acme, Inc.",Technology,1000000
0015g00000ABCDF,Globex,Manufacturing,2500000
0015g00000ABCDG,"Initech ""HQ""",Software,500000
Why CSV and nothing else
CSV is the universal data interchange format — every spreadsheet, every database, every ETL tool reads and writes it. Salesforce picked it because it’s the lowest common denominator: an admin with Excel can produce one, and a custom script with pandas.to_csv() can produce one.
Encoding (the bit people miss)
CSV doesn’t specify an encoding. The default on Windows is Windows-1252 (CP1252); Salesforce expects UTF-8.
For special characters (accents, CJK, emoji) you need to:
- Save as UTF-8 CSV in your editor.
- Tick Read UTF-8 encoding in Data Loader Settings.
The Import Wizard handles UTF-8 automatically — no toggle needed.
What Data Loader exports
When you run an Export or Export All in Data Loader, the output is also CSV. UTF-8 if you’ve ticked Write UTF-8 encoding (recommended).
Things that aren’t CSV but get confused with it
.txtfiles with commas — work if structured as CSV, but Data Loader may not auto-detect. Rename to.csv.- Excel
.xlsx— will not work directly. Save As → CSV UTF-8 first. - Tab-separated — not supported.
- Semicolon-separated — not supported, despite some European locales producing this by default in Excel. Re-export with commas.
Practical workflow
- Work in Excel / Google Sheets / your editor of choice.
- Save / Export As → CSV UTF-8 (Comma delimited).
- Optionally validate it in a text editor to confirm commas (not semicolons) and UTF-8 encoding.
- Load via Data Loader or Import Wizard.
Interview-friendly summary
“Both tools use CSV. Save as UTF-8 if you have non-ASCII characters. Each file represents one object. Data Loader also exports to CSV.” That’s the complete answer.
Verified against: Data Loader Guide — Supported Data Types, Salesforce Help — Data Import Wizard, Metadata API Developer Guide. Last reviewed 2026-05-17 for Spring ‘26 release.