Email seed list inserter: add your test addresses through a send list
In short: Upload a list, paste the test addresses you own, and they are inserted at even gaps through the list or after every set number of rows. Download the new list with the seed rows marked. Limit: It edits the list only and does not read any inbox.
Upload a list and paste the test addresses you own at Gmail, Outlook, Yahoo and others. They are inserted at even gaps through the list, or after every set number of rows, so when the send is done you can see whether mail near the start, middle or end of the send reached the inbox. Download the new list with the seed rows marked.
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
2 valid addresses. Use only inboxes you own.
Sample result
Ten example rows plus 2 seeds make 12; the seeds sit at rows 4 and 8.
- Seeds added
- 2
- List rows
- 10
- Placed
- even gaps
What this means for you
After the send, open each seed inbox to see where in the list mail began to land badly.
- Even gaps or every N rows
- Seed rows marked
- Your own addresses
- List as a CSV
- Seeds
- Inbox test
- Lead list
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Seeds added, now check the list before you send.
- Download the list with the seeds in it, 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 add seed addresses to a send list?
- Upload the list as a CSV or .xlsx, or paste the cells with the header row first. It needs a column of email addresses.
- Paste your seed addresses, one per line, and choose even gaps or one after every set number of rows.
- Press Add the seeds and read where each one sits in the list.
- Download the list, send it, and open each seed inbox when the send finishes to see where the message landed.
Example
- You enter
- Example list of ten rows and two seed addresses you own, placed at even gaps.
- You get
- Ten rows plus 2 seeds make 12 rows. The seeds sit at rows 4 and 8 of the new list, after the third and sixth contact.
- Limits
- Runs in your browser; nothing is uploaded.
What is a seed address for?
A seed is an address you own at a mailbox provider, such as a Gmail, Outlook and Yahoo inbox you can open. Putting seeds through the list means that after a send you can look at each one: if the seeds at the start reached the inbox and the ones at the end went to spam, the trouble began part-way through the send.
Seeds you add are your own addresses and are not part of the list's contacts. The download marks them so you can take them out later.
Even gaps or every N rows?
With even gaps each seed is placed so the list is cut into equal parts; four seeds on a thousand rows go in after rows 200, 400, 600 and 800. With every N rows a seed goes in after each N rows, and your seeds are used in turn and repeat. See inbox placement seed test for how to read what you find.
What does it not do?
It does not look in the inboxes for you and does not send. It also cannot make a seed behave like a real contact. Clean the list first so bounces do not confuse the result; use the email list cleaner, and split a big send with the email list splitter.
Who uses this tool, and for what?
- Cold emailers
- See whether a big send starts in the inbox and ends in spam.
- Newsletter owners
- Watch a Gmail and an Outlook seed through a full send.
- Agencies
- Give a client a simple test they can read from their own inboxes.
What can’t this tool tell you?
- It edits the list only and does not read any inbox.
- A seed shows what happened to one mailbox, not to every recipient.
- Seed rows have only the email column filled.
- Remove the seed rows before you save the list back as your contacts.
Common questions
- How many seeds should I add?
- One for each mailbox provider you want to watch, and a few more if you want to see how placement changes through a long send.
- Are the seeds marked in the download?
- Yes. A seed column holds yes on the seed rows, and the rest are blank.
- What if I add more seeds than fit?
- With even gaps they are spaced out as far as the list allows. A very short list may put two seeds side by side.
- Will the seed rows have names?
- No. Only the email column is filled on a seed row.
- Does it send the seeds anything?
- No. It only edits the list.
- Is my list uploaded anywhere?
- No. The list is read in your browser.
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.