Repeat soft bounce finder: which addresses soft-bounce send after send?
In short: Counts, per address, the distinct sends (by date or campaign) with a soft bounce (4.x.x, mailbox full, deferred, timed out). Addresses over your threshold with no delivery since go on a suppression list; ones that delivered after their last soft bounce are marked recovered; hard bounces are listed too. Limit: It reads the bounce history in the file; sends that aren't in the export aren't counted.
Upload a bounce or activity export that covers several sends, with a status or reason column and a date or campaign column. The tool counts how many different sends each address soft-bounced in. At your threshold (3 by default) with no delivery since, it goes on the suppression list; an address that delivered after its last soft bounce is kept as recovered.
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. See pricing
Sample result
1 address soft-bounced on all 3 sends; 1 recovered; 1 hard-bounced too.
- To suppress
- 2
- Watch
- 1
- Threshold
- 3 sends
What this means for you
Suppress the two dead ones and keep the rest: one soft bounce isn't a reason to remove anyone.
- Distinct sends per address
- Recovered addresses kept
- Hard bounces listed too
- Suppression list to download
- Soft bounces
- Suppression
- List hygiene
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
How do I check the addresses that soft-bounced only once or twice?
- Keep the watch and one-off addresses on the list; one soft bounce isn't a reason to remove anyone.
- Upload them at /verify to see whether each mailbox still exists. The first 100 email checks are free with a Google sign-in, no card.
- Remove the invalid ones before the next send instead of waiting for more soft bounces.
How do I find addresses that keep soft bouncing?
- Export bounces or all activity for the last several campaigns, with the email, the bounce type or reason and the date or campaign name.
- Paste it or upload the CSV, and set how many sends with a soft bounce count as dead (3 by default).
- Press Find repeat soft bounces and read the verdict per address.
- Download the suppression list and add it to your platform's suppression or do-not-contact list.
Example
- You enter
- A 10-row bounce and activity export over three sends (1, 8 and 15 October) with event, reason and date columns, for five addresses.
- You get
- 1 address to suppress (
ana@soft-bounced with 4.2.2 mailbox full on all 3 send days), 1 already hard-bounced (sam@, 5.1.1), 1 to watch (kim@, 2 sends), 1 recovered (leo@delivered on 8 October after a deferral) and 1 one-off kept. The suppression list has 2 addresses. - Limits
- Runs in your browser with no row cap; an uploaded file can be up to 25 MB.
When is a soft bounce a dead address?
A soft bounce is a temporary failure, class 4 in RFC 3463 terms: a full mailbox, a server that's down, greylisting, a rate limit. Your server retries, and one soft bounce says nothing about whether the address is good. The same address soft-bouncing on send after send, with no delivery in between, is a mailbox nobody is emptying.
Platforms draw the line in different places. Mailchimp, for example, cleans an inactive contact after 7 soft bounces (soft vs. hard bounces). This tool defaults to 3 distinct sends because each extra send to a dead mailbox counts against you, and you can set your own number. Handling soft bounces covers the timings.
How sends are counted
By the date column, one send per day; else by a campaign, sequence or subject column; else each row is one send. Several soft bounces from the same day's retries count once. A delivered row in a later send than the last soft bounce marks the address recovered, and a hard bounce anywhere puts it straight on the suppression list.
Codes and wording are read together: 4.x.x codes and words like mailbox full, deferred, timed out or try again are soft; 5.1.x and 5.2.x codes are hard, following RFC 3463. For one bounce in detail, the bounce message analyzer explains the code.
Who uses this tool, and for what?
- Newsletter senders
- Clear out mailboxes that have been full for months before they turn into hard bounces or spam traps.
- Cold emailers
- Find leads that soft-bounced on every step of a sequence and stop paying to send to them.
- Marketing ops
- Apply one soft-bounce rule across exports from two platforms during a migration.
What can’t this tool tell you?
- It reads the bounce history in the file; sends that aren't in the export aren't counted.
- Without a date or campaign column, retries of one send can look like several sends.
- A soft bounce caused by a block on your sender (4.7.x) is counted as soft; check Bounce Doctor if many share one provider.
- It can't tell whether an address that soft-bounced once still exists. That needs a mailbox check.
Common questions
- How many soft bounces before removing an email?
- There's no standard. Mailchimp cleans after 7; this tool defaults to 3 distinct sends with no delivery in between, and lets you change it.
- Is mailbox full a soft or hard bounce?
- Usually soft (4.2.2). Some servers return it as 5.2.2, a permanent failure; the tool follows the code it's given and counts 5.2.x as hard.
- Does it work with one campaign's export?
- It needs several sends to find repeats. With one send, every address has at most one soft bounce and is kept.
- Is my file uploaded?
- No. It's read in your browser.
Sources
Clean the list before the next send.
A bounce report only tells you about the addresses you already mailed. The rest of the list has the same kinds of dead mailboxes in it, and each one becomes a hard bounce recorded against your domain the moment you send.
- A real SMTP mailbox check on every row, before anything is sent
- Dead and mistyped addresses split out, so they never reach your sending tool
- Catch-all, disposable and role addresses flagged alongside
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.