Aspose.Email FOSS for Python

Aspose.Email FOSS for Python is a pure Python toolkit for working with:

• Compound File Binary (CFB) containers
• Outlook MSG files
• High-level MAPI-style message objects
• email.message.EmailMessage conversion

It is focused on practical MSG read/write workflows in a lightweight open-source package.

Features

• Read CFB and Outlook MSG containers
• Inspect low-level storages, streams, and property bags
• Read, edit, and write messages through MapiMessage
• Work with recipients, attachments, and embedded messages
• Convert between MSG and email.message.EmailMessage
• Create new Outlook-compatible .msg files in pure Python

Installation

pip install aspose-email-foss

Quick Start

from datetime import datetime, timezone

from aspose.email_foss import msg

message = msg.MapiMessage.create("Hello", "Body")
message.set_property(msg.PropertyId.SENDER_NAME, "Build Agent")
message.set_property(msg.PropertyId.SENDER_EMAIL_ADDRESS, "build.agent@example.com")
message.set_property(msg.PropertyId.MESSAGE_DELIVERY_TIME, datetime(2026, 3, 15, 10, 30, tzinfo=timezone.utc))
message.add_recipient("alice@example.com", display_name="Alice Example")
message.add_attachment("hello.txt", b"sample attachment\n", mime_type="text/plain")
message.save("example-message.msg")

with msg.MapiMessage.from_file("example-message.msg") as loaded:
    email_message = loaded.to_email_message()
    print(email_message["Subject"])

Package Entry Points

• aspose.email_foss.msg.MapiMessage: high-level mutable MSG model
• aspose.email_foss.msg.MsgReader: low-level MSG reader
• aspose.email_foss.msg.MsgWriter: low-level MSG writer
• aspose.email_foss.cfb.CFBReader: low-level CFB reader
• aspose.email_foss.cfb.CFBWriter: low-level CFB writer

Compatibility

Main supported scenarios:

• Read Outlook .msg files
• Write Outlook .msg files
• Inspect Compound File Binary (CFB) containers
• Convert .msg to .eml
• Convert .eml to .msg
• Work with recipients, attachments, and embedded messages

API layers:

• High-level MSG API: aspose.email_foss.msg, centered around MapiMessage
• Low-level MSG API: aspose.email_foss.msg, centered around MsgReader, MsgWriter, and MsgDocument
• Low-level CFB API: aspose.email_foss.cfb, centered around CFBReader, CFBWriter, and CFBDocument

email.message.EmailMessage interop:

• MapiMessage.from_email_message(...)
• MapiMessage.to_email_message()

Outlook-oriented behavior:

• standard message creation
• recipients
• file attachments
• embedded message attachments
• common message property defaults for practical Outlook interoperability

For the stable API summary, see PUBLIC_API.md. For runnable scenarios, see examples.

Examples

Convert MSG to EML

from aspose.email_foss import msg

with msg.MapiMessage.from_file("message.msg") as message:
    email_message = message.to_email_message()

with open("message.eml", "wb") as target:
    target.write(email_message.as_bytes())

Convert EML to MSG

from email import policy
from email.parser import BytesParser

from aspose.email_foss import msg

with open("message.eml", "rb") as source:
    email_message = BytesParser(policy=policy.default).parse(source)

message = msg.MapiMessage.from_email_message(email_message)
message.save("message.msg")

Useful Links

• Repository: https://github.com/aspose-email-foss/Aspose.Email-FOSS-for-Python
• Aspose.Email for Python product page: https://products.aspose.com/email/python-net/
• Aspose.Email for Python documentation: https://docs.aspose.com/email/python-net/
• Aspose.Email support forum: https://forum.aspose.com/c/email/9

Development

See CONTRIBUTING.md.

Security

See SECURITY.md.

Changelog

See CHANGELOG.md.