# Automate Python emails with attachments that get delivered

DevFeed: [Automate Python emails with attachments that get delivered](<https://devfeed.tech/articles/automate-python-emails-with-attachments-that-get-delivered-16078.md>)

Original publisher: [Read original article](<https://postmarkapp.com/blog/automate-python-emails-with-attachments-that-get-delivered>)

Author: Greg Svoboda (gsvoboda@activecampaign.com)

Published: 2026-06-30T15:08:00Z

Content type: tutorial

Language: en

Sources: [Postmark (en-US)](<https://devfeed.tech/sources/postmark-en-us.md>)

Topics: [Python](<https://devfeed.tech/topics/python.md>), [Security](<https://devfeed.tech/topics/security.md>)

Tags: [attacks](<https://devfeed.tech/tags/attacks.md>), [best-practices](<https://devfeed.tech/tags/best-practices.md>), [code](<https://devfeed.tech/tags/code.md>), [deliverability](<https://devfeed.tech/tags/deliverability.md>), [email-delivery](<https://devfeed.tech/tags/email-delivery.md>), [files](<https://devfeed.tech/tags/files.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [phishing](<https://devfeed.tech/tags/phishing.md>), [python](<https://devfeed.tech/tags/python.md>), [security](<https://devfeed.tech/tags/security.md>), [zip](<https://devfeed.tech/tags/zip.md>)

## AI overview

This tutorial explains how to automate Python emails with attachments while improving deliverability. It covers common causes of attachment-related bounces, including security policies, sender reputation, and inbox-provider restrictions, and recommends examining SMTP bounce messages and error reports.

## Source excerpt

Some of the most important emails require attachments, such as receipts, order confirmations, contracts, or digital assets. You need those emails to arrive automatically and reliably when customers and partners expect them. But attachments tend to increase bounce rates due to either security concerns, reduced engagement signals, or inbox provider policies, making deliverability harder to guarantee. A few key practices help you get top-tier deliverability when email attachments really matter: Follow general email guidelines Understand where problems happen and how to spot them Create processes that put best practices in motion Automate to scale your success for a higher volume Below, we'll show you how to implement these practices in a Python application. Why emails with attachments fail delivery Email bounces happen for a host of reasons. If you send attachments and see bounces, those files are likely causing delivery failures. Attachments pose security risks Phishing and malware attacks often use attachments, so inbox providers scrutinize them closely: Providers automatically block anything executable or compressed (e.g., .7z, .rar, .exe). This policy often extends to .zip files. Providers see red flags when you send unsolicited attachments, especially from new domains, even for "safe" file types like PDFs. Attachments affect sender reputation Recipients tend to avoid opening messages with unexpected attachments. Lower open rates, in turn, harm your domain reputation, making it even harder to deliver your emails. Improving your deliverability starts with digging into exactly where you're having problems. The first resource to consult is SMTP bounce messages. Study your bounce messages If your emails regularly bounce back, it's fair to assume the underlying issue is the file attachments. You can find out more by examining the error reports. The Postmark dashboard helps you make sense of errors. If you don't have the tool set up, you can look into the bounce messages