Top Downloaded Python Packages on PyPI in the Past Year

1. Urllib3: 893 million downloads

Urllib3 is a Python HTTP client that provides many features not available in the standard library, such as thread safety, connection pooling, SSL/TLS verification, multipart file upload, request retry, gzip/deflate support, and proxy handling.

Although its name suggests it is a successor to urllib2, it is a separate third‑party library; for core functionality you may use urllib.request . For end users, the requests library is often recommended.

2. Six: 732 million downloads

Six is a compatibility library that enables code to run on both Python 2 and Python 3 by providing functions that mask syntax differences, such as six.print_() .

Key points: the name comes from 2 × 3 = 6; similar libraries include future ; for converting code to Python 3 only, see 2to3 . The author encourages dropping Python 2 support.

3. Botocore, Boto3, s3transfer, AWSCLI

These projects are related:

Botocore – 660 million downloads (rank 3)

s3transfer – 584 million downloads (rank 7)

AWSCLI – 394 million downloads (rank 17)

Boto3 – 329 million downloads (rank 22)

Botocore is the low‑level AWS interface and the foundation for Boto3, which provides access to services like S3 and EC2. Botocore also underlies the AWS CLI. s3transfer manages S3 transfers and is a dependency of Boto3 and the CLI.

4. Pip: 627 million downloads

Pip is the standard Python package installer, allowing easy installation from PyPI or custom repositories.

Pip Installs Packages (recursive name)

Install with pip install <package> , uninstall with pip uninstall <package>

Supports requirements files for pinned versions

Works well with virtualenv to create isolated environments

5. python-dateutil: 617 million downloads

python-dateutil extends the standard datetime module with powerful parsing capabilities.

Example: parsing fuzzy timestamps from log lines.

<code>from dateutil.parser import parse

logline = "INFO 2020-01-01T00:00:01 Happy new year, human."
timestamp = parse(logline, fuzzy=True)
print(timestamp)  # 2020-01-01 00:00:01</code>

6. Requests: 611 million downloads

Requests builds on urllib3 to make HTTP requests extremely simple.

Example usage:

<code>import requests

r = requests.get("https://api.github.com/user", auth=(user, pass))
print(r.status_code)          # 200
print(r.headers["content-type"])  # application/json; charset=utf8
print(r.encoding)             # utf-8
print(r.text)                # raw response text
print(r.json())              # parsed JSON</code>

7. s3transfer

See section 3 for details; it is closely related to the AWS packages.

8. Certifi: 552 million downloads

Certifi provides a curated collection of root SSL certificates, enabling Python code to verify HTTPS connections just like browsers do.

Many projects depend on Certifi for secure network communication.

9. Idna: 527 million downloads

Idna implements the Internationalized Domain Names in Applications (IDNA) protocol, allowing conversion between Unicode domain names and ASCII representations.

Core functions are idna.encode() (Unicode → ASCII) and idna.decode() (ASCII → Unicode).

<code>import idna
print(idna.encode('ドメイン.テスト'))  # b'xn--eckwd4c7c.xn--zckzah'
print(idna.decode('xn--eckwd4c7c.xn--zckzah'))  # ドメイン.テスト</code>

10. PyYAML: 525 million downloads

PyYAML is a YAML parser and emitter for Python, allowing reading and writing of YAML files, which are more expressive than INI files.

YAML supports native data types, nested structures, and automatic type detection.

<code>config.getint("section", "my_int")
# vs
config["section"]["my_int"]  # PyYAML auto‑detects int</code>

11. pyasn1: 512 million downloads

pyasn1 is a pure‑Python implementation of ASN.1 types and DER/BER/CER encoding, a historic data‑serialization standard used in many security protocols.

It is a low‑level dependency for libraries handling certificates and other binary protocols.

12. docutils: 508 million downloads

Docutils converts plain text (reStructuredText) into formats like HTML, XML, and LaTeX, and is used by the Python Enhancement Proposal (PEP) documentation system and Sphinx.

13. Chardet: 501 million downloads

Chardet detects the character encoding of byte streams, useful for processing unknown text files.

Command‑line usage:

<code>chardetect somefile.txt
# output: somefile.txt: ascii with confidence 1.0</code>

It is also a dependency of requests and many other libraries.

14. RSA: 492 million downloads

RSA is a pure‑Python implementation of the RSA algorithm, supporting encryption/decryption, signing/verification, and PKCS#1 v1.5 key generation.

Example:

<code>import rsa
(bob_pub, bob_priv) = rsa.newkeys(512)
crypto = rsa.encrypt('hello Bob!', bob_pub)
message = rsa.decrypt(crypto, bob_priv)
print(message.decode('utf8'))  # hello Bob!</code>

Many packages (e.g., google-auth , oauthlib , awscli ) depend on it.

15. Jmespath: 473 million downloads

JMESPath provides a declarative way to query JSON data in Python.

Basic examples:

<code>import jmespath

d = {"foo": {"bar": "baz"}}
print(jmespath.search('foo.bar', d))  # baz

# Wildcard example
 d = {"foo": {"bar": [{"name": "one"}, {"name": "two"}]}}
print(jmespath.search('foo.bar[*].name', d))  # ['one', 'two']
</code>