fast_mail_parser is a Python library for .eml files parsing. The main benefit is a performance: the library is much faster than python implementations.
Based on mailparse library using pyo3.
-------------------------------------------------------------------------------------------- benchmark: 2 tests -------------------------------------------------------------------------------------------
Name (time in ms) Min Max Mean StdDev Median IQR Outliers OPS Rounds Iterations
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test__fast_mail_parser___parse_message 1.8136 (1.0) 1.8938 (1.0) 1.8426 (1.0) 0.0176 (1.0) 1.8465 (1.0) 0.0277 (1.0) 180;0 542.7141 (1.0) 450 1
test__mail_parser___parse_message 14.5583 (8.03) 15.8571 (8.37) 15.0264 (8.16) 0.2368 (13.49) 14.9702 (8.11) 0.2887 (10.42) 5;1 66.5495 (0.12) 32 1
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Legend:
Outliers: 1 Standard Deviation from Mean; 1.5 IQR (InterQuartile Range) from 1st Quartile and 3rd Quartile.
OPS: Operations Per Second, computed as 1 / Mean
Use the package manager pip to install fast_mail_parser.
pip install fast-mail-parserWheels target the CPython stable ABI (cp311-abi3): one wheel per platform
covers every supported CPython version, including versions released after the
package — a new Python no longer has to wait for a new release.
| Python | Support |
|---|---|
| CPython 3.11+ (including future versions) | Prebuilt wheel |
| CPython 3.13t/3.14t (free-threaded) | Builds from source; the extension currently re-enables the GIL on import (#101) |
| CPython ≤ 3.10 | Not supported (last compatible release: 0.2.5) |
| PyPy | Not supported |
parse_email accepts the raw message as str or bytes and returns a
PyMail. It raises ParseError if the payload cannot be parsed.
PyMail exposes the following attributes:
| Attribute | Type | Description |
|---|---|---|
subject | str | Subject header (empty string if missing). |
date | str | Date header (empty string if missing). |
text_plain | list[str] | All text/plain bodies. |
text_html | list[str] | All text/html bodies. |
headers | dict[str, str] | All message headers. |
attachments | list[PyAttachment] | Attachments (see below). |
Each PyAttachment has mimetype: str, filename: str, and content: bytes.
importsysfromfast_mail_parserimportparse_email, ParseError# parse_email accepts both str and bytes; reading in binary mode is safest.withopen('message.eml', 'rb') asf:
message_payload=f.read()
try:
email=parse_email(message_payload)
exceptParseErrorase:
print("Failed to parse email:", e)
sys.exit(1)
print("Subject:", email.subject)
print("Date:", email.date)
# headers is a dict[str, str].forname, valueinemail.headers.items():
print(f"{name}: {value}")
# text_plain and text_html are lists of strings (one entry per matching part).forbodyinemail.text_plain:
print("Plain text body:", body)
forbodyinemail.text_html:
print("HTML body:", body)
# attachments is a list of PyAttachment objects.forattachmentinemail.attachments:
print("Attachment:", attachment.filename)
print(" mimetype:", attachment.mimetype)
print(" size:", len(attachment.content), "bytes") # content is bytesPull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
Please make sure to update tests as appropriate.
See CONTRIBUTING.md for how to build from source, run the tests, and the PR conventions (linting, CI, DCO sign-off).