Postfix log summarizer: sent, deferred and bounced from your mail log
In short: Paste lines from the Postfix mail log. The tool counts status=sent, deferred and bounced, groups the reasons with the code, shows each recipient domain and gives you the bounced addresses as a file. Limit: It reads Postfix's status= lines; other mail servers write different lines.
Paste lines from your Postfix mail log and the tool reads each line with to=<address> and status=. It counts sent, deferred and bounced mail, groups the reasons after removing addresses and IPs, lists results per recipient domain, and gives you a file of addresses whose last line says bounced, ready to suppress.
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
Sample result
Five delivery lines: 2 sent, 1 deferred and 2 bounced.
- Bounced
- 2
- Delivery lines
- 5
- Sent
- 2
What this means for you
Both bounces share one cause and one domain, so the fix is in the list, not the server.
- Sent, deferred, bounced
- Reasons grouped
- Results by domain
- Bounced addresses file
- Postfix
- Mail log
- Bounces
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
The log shows what happened. A check stops it before the next send.
- Download the bounced addresses, or collect the recipients you plan to mail next.
- 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 summarise a Postfix log?
- Copy the delivery lines from your mail log, for example the lines that contain status=. Paste them in.
- Read the counts, the grouped reasons and the table of recipient domains.
- Download the bounced addresses to suppress, or every delivery line as a CSV.
- Check the whole list before the next send so those addresses never reach a server.
Example
- You enter
- Example log of five delivery lines: ava@example.com and cara@example.org sent, cara@example.org deferred first, ben@example.net and dev@example.net bounced with 550 5.1.1 user unknown.
- You get
- Five delivery lines read: 2 sent, 1 deferred and 2 bounced. The two bounces share one reason (5.1.1) and both are on example.net. Two addresses, ben@example.net and dev@example.net, are in the bounced file.
- Limits
- Runs in your browser; nothing is uploaded.
What do sent, deferred and bounced mean?
Sent means the next mail server accepted the message. It does not say the message reached an inbox. Deferred means a temporary failure, and Postfix keeps the message and tries again. Bounced means a permanent failure, and Postfix gives up and returns the message to the sender.
The dsn field holds the status code, such as 5.1.1 or 4.2.0. For what a code means, use the bounce message analyzer.
How are the reasons grouped?
The text in brackets after the status is the receiving server's own words. The tool replaces addresses, IP addresses and long ids in it, so a hundred bounces that say the same thing become one row with a count. Reasons for deferred and bounced lines are grouped separately by status and code.
Why look by recipient domain?
Bounces from one receiving domain usually mean a block on that provider, while bounces spread over many domains point to a stale list. Use the domain table to tell which. For a list-wide view, see find which domains cause your bounces.
Who uses this tool, and for what?
- Self-hosted senders
- Turn a day of log lines into a count and a suppression file.
- Deliverability engineers
- Group thousands of bounce lines by cause and by receiving domain.
- Sales ops
- Pull the bounced addresses out of a log and remove them from the CRM.
What can’t this tool tell you?
- It reads Postfix's status= lines; other mail servers write different lines.
- Only the lines you paste are counted, so it cannot see lines outside the paste.
- A sent line means the next server accepted the message, not that anyone read it.
- It reads the text of the reason; it does not look anything up.
Common questions
- Which log lines does it read?
- Any line that holds both to=<address> and status=, which is how Postfix's smtp and lmtp delivery agents write each delivery attempt. Other lines are skipped.
- Does a message to several recipients count once?
- No. Postfix writes one line per recipient and each is counted.
- How do I get the log lines?
- Copy them from your mail log file, for example with a search for status=. Where the file lives depends on your system.
- Why does one address appear as deferred and then sent?
- A deferral is retried. The bounced file uses each address's last line, so an address that was deferred and then sent is not listed as bounced.
- Does it change anything on my server?
- No. It only reads the text you paste, in your browser.
- Is my log uploaded?
- No. It stays 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.