CSV import formatter for Instantly, Smartlead and lemlist
A CSV import formatter rewrites a lead file into the format a sending tool imports cleanly. Choose Instantly, Smartlead or lemlist, upload any CSV, and match your columns to its fields; the tool renames headers, keeps other columns as custom variables, converts the file to UTF-8 with commas, trims spaces and drops rows with no email.
Which tool are you importing into?
Columns out: Email, First Name, Last Name, Company Name, Website, then your other columns as custom variables. Rules from Instantly: How to import leads via CSV, checked 17 October 2026. Starting from scratch? Use the empty template instead.
Sample result
2 leads are ready to import; a row with no email was removed.
- Leads in the file
- 2
- No email (removed)
- 1
- Repeat emails
- 1
What this means for you
The file loads cleanly into your sending tool, with columns already matched to its fields.
- Maps your columns to the tool's own fields
- Names custom variables the way it expects
- Repairs garbled accents and stray spaces
- Drops rows with no email and repeat emails
- Import
- Mapping
- UTF-8
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I format a CSV for Instantly, Smartlead or lemlist?
- Choose the tool you are importing into: Instantly, Smartlead or lemlist.
- Paste the CSV or upload the export, then press Read columns. Semicolon and tab separated files, Windows-1252 and UTF-16 files are read too.
- Check the suggested match for each field and change any that are wrong. Email is the only required one.
- Press Format, review the preview and the list of what changed, then download the file and upload it in your sending tool.
Example
- You enter
- A lead export with 3 rows for Smartlead:
jane.doe@acme.example,bob@acme-mail.exampleand one row with no email. - You get
- A UTF-8, comma-separated file with 2 leads under Smartlead's own column names (email, first_name, last_name, company_name, website, location); the row with no email is removed.
- Limits
- Runs in your browser with no row cap; an uploaded file can be up to 25 MB.
What is the correct CSV format for Instantly?
Instantly wants column names in row 1, an email address in every row, and the file saved as UTF-8. Its CSV import guide also asks for column names that start with a capital letter, are no longer than 20 characters and aren't repeated, at most 50 variables per upload, no TRUE/FALSE values and no extra whitespace in cells. The Email column is mandatory and must be mapped to Email.
The formatter writes the headers Instantly maps on its own (Email, First Name, Last Name, Company Name, Website), turns your other columns into capitalised names of 20 characters or fewer, stops adding custom columns at the 50-column cap and lists any it left out.
How do I prepare a CSV file for Smartlead or lemlist?
For Smartlead, keep one row per lead with the email in its own column; Smartlead's mapping guide maps standard fields such as name, email and location automatically and allows up to 40 custom variables per lead, used in copy as placeholders like {{first_name}}. The formatter names custom columns in that snake_case style so the placeholder you write matches the column.
For lemlist, row 1 must be column names, every row needs an email (it is the lead's unique ID), and column names should have no spaces, as its CSV import guide says. Variable names are case-sensitive and custom variables hold up to 2,000 characters, per its variables guide. The formatter writes custom columns in camelCase (jobTitle) and flags values over 2,000 characters.
What is the difference between CSV and CSV UTF-8?
CSV UTF-8 stores accented and non-Latin characters in UTF-8, while plain CSV from older Excel on Windows usually uses a regional code page such as Windows-1252, so "José" can arrive as "Jos?" or "José". Instantly asks for UTF-8 and lemlist warns that non-UTF-8 files turn accents into diamond symbols. The WHATWG Encoding Standard defines both encodings browsers read.
The formatter reads UTF-8, UTF-16 (Excel's Unicode Text) and Windows-1252 files, repairs cells that were already garbled the "José" way, and always writes UTF-8. The download has no byte-order mark unless you tick the option, which some spreadsheet apps rely on to recognise UTF-8.
How do I fix a CSV file whose columns are all in one column?
That file is separated by semicolons or tabs instead of commas, which Excel can do when the computer's list separator is set to a semicolon. RFC 4180 describes CSV as comma separated, and the sending tools expect commas. The formatter detects the separator from the header row and writes commas, quoting any cell that contains a comma, quote or line break.
If you need a fresh file rather than a converted one, the email list template has an empty CSV for each tool, and CSV merge combines several exports into one before you format it.
How do Instantly, Smartlead and lemlist differ on CSV imports?
| Instantly | Smartlead | lemlist | |
|---|---|---|---|
| Email column | Required, mapped to Email | Mapped automatically | Required, the lead's unique ID |
| Header style | Capital first letter, ≤20 characters, no duplicates | Placeholders like {{first_name}} | Case-sensitive, no spaces |
| Custom variable limit | 50 variables per upload | 40 per lead | Not capped; values ≤2,000 characters |
| Encoding | UTF-8 (Excel's CSV UTF-8) | Not stated in the guide | UTF-8, pure .csv |
From each tool's own import guide, linked under Sources.
Who uses this tool, and for what?
- Cold emailers
- Turn an Apollo, Sales Navigator or scraped export into a file Instantly maps on the first try, with job title and city kept as variables.
- Agencies
- Move a client's lead list between Smartlead and lemlist without hand-renaming twenty columns for each tool's naming style.
- SDR teams
- Fix the semicolon-separated, accent-garbled files that come out of Excel in European offices before a campaign goes live.
- RevOps
- Drop rows with no email and repeated leads before import, so the tool's lead count matches what you pay for.
What can’t this tool tell you?
- Field names and limits are from each tool's help centre as checked on 17 October 2026; the tool's own mapping screen has the final say.
- Emails are lowercased and checked for shape only; it doesn't tell you whether the mailbox exists.
- It can't split a full name into first and last names; use the name splitter for that first.
- Duplicates are matched on the exact email, so
jane+news@andjane@count as different leads. - Garbled-accent repair only fixes text that was UTF-8 read as Windows-1252; other mix-ups are left as they are.
Common questions
- What is the correct format for a CSV file?
- Column names in the first row, one record per row, values separated by commas, and any value that contains a comma, quote or line break wrapped in double quotes, as RFC 4180 describes. Sending tools also want UTF-8 and an email column.
- How to fix CSV file format?
- Re-save it as CSV UTF-8 with commas, make sure row 1 holds column names, and remove empty rows. The formatter above does all three and renames the columns for Instantly, Smartlead or lemlist.
- What's the difference between CSV and CSV UTF-8?
- Only the character encoding. CSV UTF-8 keeps accents and non-Latin names intact; plain CSV from older Excel versions uses a regional code page that turns them into question marks or garbled text when another tool opens the file.
- Which CSV file format should I use?
- For Instantly, Smartlead and lemlist, use comma-separated CSV in UTF-8. Instantly's guide names Excel's CSV UTF-8 (comma delimited) option, and lemlist asks for pure CSV rather than .xlsx.
- How to check CSV file format?
- Open the file in a text editor: row 1 should be names, values should be separated by commas, and accented names should look right. The formatter reports the separator and encoding it found when you press Read columns.
- How to prepare a CSV file?
- Put one lead per row with an email in every row, give each column a short unique name, delete empty rows and columns, and save as CSV UTF-8. Then match the names to your sending tool's fields, which the formatter does for you.
Sources
A tidy list can still be full of dead addresses.
Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.
- Upload the cleaned file as it is: CSVs up to 100,000 rows
- A real SMTP mailbox check on every row, with catch-all detection
- Small list? $9 one-time covers 2,500 emails, no subscription
One plan, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.