lemlist lead CSV formatter: headers lemlist maps on its own
In short: Upload any export (.xlsx or CSV) or paste cells. The tool writes email, firstName, lastName, companyName, companyDomain and phone using lemlist's standard variable names, merges repeats and warns above 10,000 rows. Limit: Only the six standard variables above are written; linkedinUrl, picture and icebreaker are not.
lemlist's help center lists standard variables it maps automatically when the header matches exactly: email (required), firstName, lastName, companyName, companyDomain, phone and others. Upload your export here to get those headers, with emails cleaned, repeats merged and a warning when a file passes 10,000 leads.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. Check your list free nowSee pricing
Used only to complete phone numbers.
Sample result
Jane Doe at Northwind becomes one row with email, firstName, lastName, companyName, companyDomain and phone.
- Rows
- 2 leads
- Per file
- 10,000 leads
- Repeats merged
- 1
What this means for you
The headers match lemlist's standard variable names, so it can map them automatically.
- Standard variable names
- Website cut to a domain
- +country-code phones
- 10,000-row warning
- lemlist
- Leads
- CSV
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Check the addresses before they go into lemlist.
- Export the email column from the file you just made, or use the check button under the result.
- Upload or paste it at /verify. Every address gets a live mailbox check, and the first 100 email checks are free with a Google sign-in, no card.
How do I prepare a CSV for a lemlist import?
- Upload the export (.xlsx or CSV), or paste the cells with the header row first.
- Choose the country used for phone numbers written without a + country code.
- Check the columns found, the rows left out and any size warning, then download the CSV.
- In lemlist, import leads from a CSV and confirm the default email column on the mapping step.
Example
- You enter
- A sheet with Full Name, Work Email, Mobile, Country, Company and Website:
Jane Doe,Jane@Example.com,(415) 555-0132,United States,Northwind,https://www.northwind.example/about;Leo Martinwithleo@example.org; l.martin@example.org; a repeat row forjane@example.com; and a row with only a phone,(212) 555-0100. - You get
- Two leads under email, firstName, lastName, companyName, companyDomain and phone:
jane@example.com, Jane, Doe, Northwind,northwind.example,+14155550132, andleo@example.org, Leo, Martin. The repeat is merged, Leo's second address is dropped and counted, and the phone-only row is left out. - Limits
- Runs in your browser; nothing is uploaded. Files up to 25 MB.
Which headers does lemlist map automatically?
lemlist's import guide says to match its standard names exactly for automatic mapping: email (required), firstName, lastName, companyName, companyDomain, linkedinUrl, phone, picture and icebreaker. The first row holds column names, there are no empty rows between leads and column names should have no spaces. See lemlist's CSV import guide.
What does the tool write?
email, firstName, lastName, companyName, companyDomain and phone. A website cell is cut down to a bare domain for companyDomain, a full-name column is split, and phone numbers are written with a + and country code. Columns your export has no data for are left out except the identity columns.
What are lemlist's size limits?
lemlist's import-limits page says you can upload up to 40,000 leads in total via CSV, with a maximum of 10,000 leads per CSV file. This tool warns when the result passes 10,000 rows so you can split the file first. The guide also asks for plain UTF-8 CSV, not an Excel CSV variant; the download is UTF-8.
Who uses this tool, and for what?
- Cold email teams
- Get exports from any source into lemlist's standard variable names.
- Agencies
- Prepare client lists to the same header format every time.
- Sales ops
- Catch a list that is over the 10,000-per-file limit before the upload fails.
What can’t this tool tell you?
- Only the six standard variables above are written; linkedinUrl, picture and icebreaker are not.
- The tool warns above 10,000 rows but does not split the file; use the list splitter for that.
- Name splitting follows Western name order.
- Campaign and sending settings are in lemlist, not here.
Common questions
- Which column does lemlist require?
- email. The guide says every lead must have one, because it is the lead's unique ID.
- Are lemlist header names case-sensitive?
- The guide says to match the standard names exactly, so firstName and lastName are written that way here.
- How many leads can one CSV hold?
- lemlist's import-limits page lists a maximum of 10,000 leads per CSV file and 40,000 leads in total by CSV.
- Can I add my own variables?
- Yes. Extra columns can use any name, and the header becomes the variable name. Avoid spaces in names.
- Is my list uploaded to SimpleVerifier?
- No. The file is read and rewritten in your browser.
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? Starter at $9/mo covers 2,500 emails a month, cancel anytime
Plans from $9 a month, 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.