Top 22 Most Downloaded Python Packages and Their Uses

The author compiled a list of the 22 most downloaded Python packages on PyPI to illustrate their purposes, relationships, and popularity, aiming to give readers useful guidance on essential Python tools.

1. urllib3

8.93 billion downloads – a powerful HTTP client offering thread safety, connection pooling, SSL/TLS verification, multipart file upload, request retry, proxy support, and compression handling.

Thread‑safe

Connection pool

SSL/TLS verification

Multipart upload

Retry & redirect handling

gzip/deflate support

HTTP and SOCKS proxy support

For end users, requests is recommended; urllib3 ranks first because many other packages depend on it.

2. six

7.32 billion downloads – a compatibility library that smooths differences between Python 2 and Python 3, providing functions such as six.print_() to write version‑agnostic code.

Name derives from 2 × 3 = 6

Related libraries: future

For Python 2→3 conversion, see 2to3

3. botocore, boto3, s3transfer, awscli

These AWS‑related packages rank high due to the popularity of Amazon services. botocore (6.6 billion downloads) is the core of boto3 , which provides Python APIs for S3, EC2, etc. s3transfer manages S3 transfers, and awscli is the AWS command‑line interface.

4. pip

6.27 billion downloads – the standard Python package installer, supporting installation from PyPI, private indexes, and requirement files.

Recursive name: "Pip Installs Packages"

Simple install/uninstall commands

Works with virtualenv for isolated environments

5. python-dateutil

6.17 billion downloads – extends the built‑in datetime module with powerful parsing and manipulation capabilities.

<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

6.11 billion downloads – a user‑friendly HTTP library built on top of urllib3.

<code>import requests
r = requests.get('https://api.github.com/user', auth=('user','pass'))
print(r.status_code)  # 200
print(r.headers['content-type'])
print(r.json())</code>

7. s3transfer

Related to the AWS packages above; see the botocore section.

8. certifi

5.52 billion downloads – provides a curated collection of root SSL certificates for verifying HTTPS connections in Python.

9. idna

5.27 billion downloads – implements Internationalized Domain Names (IDNA) encoding/decoding.

<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

5.25 billion downloads – parses and emits YAML, offering richer configuration handling than configparser .

11. pyasn1

5.12 billion downloads – pure‑Python implementation of ASN.1 encoding/decoding, foundational for many security protocols.

12. docutils

5.08 billion downloads – converts reStructuredText to HTML, XML, LaTeX, and powers tools like Sphinx.

13. chardet

5.01 billion downloads – detects character encodings in byte streams.

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

14. rsa

4.92 billion downloads – pure‑Python RSA implementation for encryption, signing, and key generation.

<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>

15. jmespath

4.73 billion downloads – enables declarative JSON querying.

<code>import jmespath
d = {'foo': {'bar': 'baz'}}
print(jmespath.search('foo.bar', d))  # baz
</code>

16. setuptools

4.01 billion downloads – tool for building and distributing Python packages.

17. awscli

See botocore section; provides the AWS command‑line interface.

18. pytz

3.94 billion downloads – accurate and cross‑platform timezone handling.

<code>from datetime import datetime
from pytz import timezone
ams = timezone('Europe/Amsterdam')
ams_time = ams.localize(datetime(2002,10,27,6,0,0))
print(ams_time)  # 2002-10-27 06:00:00+01:00
</code>

19. futures

3.89 billion downloads – backport of concurrent.futures for Python 2.

<code>from concurrent.futures import ThreadPoolExecutor
from time import sleep

def return_after_5_secs(message):
    sleep(5)
    return message

pool = ThreadPoolExecutor(3)
future = pool.submit(return_after_5_secs, "Hello world")
print(future.done())  # False
sleep(5)
print(future.done())  # True
print(future.result())  # Hello world
</code>

20. Colorama

3.70 billion downloads – adds cross‑platform colored terminal text.

<code>from colorama import Fore, Back, Style
print(Fore.RED + 'some red text')
print(Back.GREEN + 'and with a green background')
print(Style.DIM + 'and in dim text')
print(Style.RESET_ALL)
print('back to normal now')
</code>

21. simplejson

3.41 billion downloads – faster drop‑in replacement for the built‑in json module.

22. boto3

See botocore section; the official AWS SDK for Python.

Conclusion: The most popular packages provide core functionality such as networking, compatibility, data handling, security, and tooling, and they are heavily depended upon by many other projects, making them essential for Python development.