GoBounceParser - Free IMAP Bounce Email Scanner & Extractor

GoBounceParser is a free command-line tool for scanning IMAP mailboxes, detecting email delivery failure notifications, and extracting recipient addresses from bounce messages. It is useful for cleaning mailing lists, analyzing delivery failures, and collecting addresses that may require further review.

The package includes the full Go source code, allowing developers to inspect, modify, compile, and adapt the tool for their own workflow.

Key Features

• Connects to multiple email accounts through IMAP.
• Scans all available mailbox folders.
• Processes only unread messages during subsequent scans.
• Marks successfully processed messages as read.
• Supports standard DSN (Delivery Status Notification) parsing.
• Extracts failed recipient addresses from the DSN Final-Recipient field.
• Supports an optional mode for processing regular, non-DSN messages.
• Can search for specific words or phrases inside messages.
• Can process all unread messages when the search mode is set to all.
• Removes duplicate email addresses from the output.
• Saves results to a timestamped text file.
• Supports configurable concurrent mailbox processing.
• Supports direct connections and SOCKS4, SOCKS4A, or SOCKS5 proxies.
• Supports TLS and STARTTLS IMAP connections.
• Can automatically repeat mailbox scans at a configurable interval.

Two Message Processing Modes

GoBounceParser can operate in two different modes using the dsn_only setting.

• DSN-only mode: processes standard machine-readable delivery status notifications and extracts recipients whose delivery action is reported as failed.
• All-messages mode: processes regular unread messages and searches for email addresses in common message headers and body content.

dsn_only=1

The example above enables DSN-only processing. Set the value to 0 to allow regular messages to be processed.

Search Configuration

You can restrict mailbox scanning to messages containing selected words or phrases:

search_msg_content=Undelivered|Mail delivery failed|Delivery Status Notification

Separate multiple search phrases with the | character. To scan every unread message, use:

search_msg_content=all
dsn_only=0

Output

Extracted addresses are saved to a plain-text file inside the configured results directory. Each address is written on a separate line, making the output easy to import into spreadsheets, databases, mailing-list tools, or custom applications.

user1@example.com
user2@example.net
user3@example.org

Included Source Code

This free download includes the complete Go source code used by the application. The source can be reviewed and customized to add new bounce formats, output formats, mailbox filters, proxy behavior, logging, or integration with other systems.

• Full bounce_parser.go source code
• Go module configuration
• Editable application settings
• No proprietary source-code components

Configuration Options

• Maximum number of concurrent mailbox workers
• Network and IMAP command timeouts
• Mailbox rescan interval
• Result-saving interval
• DSN-only or all-messages processing
• Message search terms
• Results directory
• Proxy type, source, rotation mode, and retry count
• Optional debug logging

Important Information

• The tool is intended only for mailboxes that you own or are authorized to access.
• Successfully processed messages are marked as read but are not deleted.
• DSN-only mode provides more accurate results than extracting every address from regular message content.
• All-messages mode may also find addresses in signatures, quoted text, forwarded messages, and other unrelated content.
• Some mail servers use non-standard bounce formats that may require additional parsing rules.
• The tool does not send emails and does not perform SMTP address verification.
• IMAP credentials are supplied locally by the user. Keep account files private and never distribute them with the application.

Recommended For

• Email administrators
• Newsletter and mailing-list operators
• Developers working with email delivery data
• Users who need to extract failed recipients from IMAP mailboxes
• Go developers looking for a customizable bounce-processing example

Price: Free

Source code included: Yes