Supported Formats & Encoding

File requirements, encoding support, and duplicate detection

File Requirements

Requirement	Value
Format	CSV only
Size limit	50MB maximum
Maximum columns	100
Maximum rows	50,000 per file

Supported Encodings

Smelt supports multiple character encodings:

Encoding	Recommendation
UTF-8	✅ Recommended — best compatibility
UTF-16	Supported
Latin-1 (ISO-8859-1)	Supported
Windows-1252	Supported

When in doubt, use UTF-8. It handles international characters and is the most widely compatible.

Exporting as UTF-8

From Excel

1. File → Save As
2. Choose “CSV UTF-8 (Comma delimited)”
3. Save

From Google Sheets

1. File → Download
2. Choose “Comma Separated Values (.csv)”
3. Google Sheets exports as UTF-8 by default

From Numbers (Mac)

1. File → Export To → CSV
2. Text Encoding: Unicode (UTF-8)
3. Export

Duplicate Detection

Smelt automatically detects duplicates in your data:

What’s Detected

Field	Detection
Emails	Exact match duplicates
Company names	Exact match duplicates
Phone numbers	Exact match duplicates
LinkedIn URLs	Exact match duplicates

Where Duplicates Are Shown

The file detail page displays:

• Duplicate count for each key field
• Which rows contain duplicates

How Duplicates Affect Processing

Duplicates are still processed — each row generates output.

Smelt doesn’t automatically remove duplicates. Each row in your CSV will:

• Be processed by your templates
• Generate its own output
• Count toward your usage

Consider deduplicating before upload if you want to:

• Save on usage costs
• Avoid sending duplicate emails
• Keep your data clean

Best Practices for CSV Formatting

Use headers in the first row

Row 1 should contain column names, not data.

Consistent column names

Keep naming consistent across files if you reuse templates.

No merged cells

CSVs don’t support merged cells. Unmerge before exporting.

Clean data

Trim whitespace, fix obvious typos, remove empty rows.

Avoid special characters in headers

Simple alphanumeric column names work best.

Common Encoding Issues

Symptom	Cause	Fix
Garbled characters (é, ’)	Wrong encoding detected	Re-save as UTF-8
Missing characters	Incompatible encoding	Re-save as UTF-8
Empty cells showing data	Hidden characters	Clean data, re-export