The 22 Most Used Python Packages in the World

What is the current usage situation of Python across global industries? This article answers that question by listing the 22 most frequently downloaded Python packages on PyPI, describing their purposes, relationships, and reasons for popularity.

1. urllib3

893 million downloads

urllib3 is an HTTP client for Python that offers many features missing from the standard library, such as thread safety, connection pooling, SSL/TLS verification, multipart file upload, request retry, gzip/deflate support, and HTTP/SOCKS proxy handling.

Although its name suggests a successor to urllib2, it is a separate library; for core functionality only, consider using urllib.request . For end users, requests is recommended.

2. six

732 million downloads

six provides compatibility utilities for writing code that runs on both Python 2 and Python 3, masking syntax differences (e.g., six.print works on both versions). The name comes from 2 × 3 = 6. Similar tools include future , and conversion tools like 2to3 are available.

3. botocore, boto3, s3transfer, awscli

These packages are interrelated:

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; boto3 builds on it to provide high‑level access to services like S3 and EC2. awscli uses botocore as its foundation. s3transfer manages S3 transfers and is a dependency of boto3 and awscli.

4. pip

627 million downloads

pip is the standard package installer for Python, allowing installation from PyPI or other indexes. Its name is a recursive acronym: "Pip Installs Packages". It 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, such as fuzzy parsing of date strings.

<code>from dateutil.parser import parse
logline = 'INFO 2020-01-01T00:00:01 Happy new year, human.'
timestamp = parse(log_line, fuzzy=True)
print(timestamp)  # 2020-01-01 00:00:01</code>

6. requests

611 million downloads

Built on top of urllib3, requests makes HTTP requests extremely simple.

<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.text)
print(r.json())</code>

7. s3transfer

See the description under item 3 for details.

8. certifi

552 million downloads

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

9. idna

527 million downloads

idna implements the Internationalized Domain Names in Applications (IDNA) protocol, offering idna.encode and idna.decode functions.

<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 parses and emits YAML, a human‑readable data serialization format, allowing conversion between Python objects and YAML.

11. pyasn1

512 million downloads

Provides a pure‑Python implementation of ASN.1 types and DER/BER/CER encoding, the basis for many security protocols.

12. docutils

508 million downloads

docutils converts plain text (reStructuredText) into formats like HTML, XML, and LaTeX. It powers the documentation pipeline for Python itself and tools such as Sphinx.

13. chardet

501 million downloads

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

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

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.

<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

473 million downloads

jmespath allows declarative extraction of data from JSON structures.

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

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

16. setuptools

401 million downloads

setuptools is the standard tool for building and distributing Python packages.

17. awscli

See item 3 for context; it depends on botocore.

18. pytz

394 million downloads

pytz provides accurate and cross‑platform timezone calculations.

<code>from datetime import datetime
from pytz import timezone
amsterdam = timezone('Europe/Amsterdam')
ams_time = amsterdam.localize(datetime(2002, 10, 27, 6, 0, 0))
print(ams_time)  # 2002-10-27 06:00:00+01:00
ams_time = amsterdam.localize(datetime(2002, 6, 27, 6, 0, 0))
print(ams_time)  # 2002-06-27 06:00:00+02:00</code>

19. futures

389 million downloads

The futures package backports the concurrent.futures module to 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

370 million downloads

colorama adds cross‑platform colored output to terminal applications.

<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

341 million downloads

simplejson is a fast JSON library compatible with the standard json module, offering broader Python version support and optional C acceleration.

<code>try:
    import simplejson as json
except ImportError:
    import json</code>

22. boto3

See item 3 for context; it builds on botocore.

In summary, the most popular packages provide core functionality such as time handling, configuration management, encryption, and networking. Many are dependencies for other projects, while others extend Python with packaging tools, documentation generators, compatibility layers, and more.