Discover the 22 Most Used Python Packages and Their Real‑World Impact

This article lists the 22 most downloaded Python packages on PyPI, explains their core functionality, shows download statistics, and provides code examples for many of them.

1. urllib3

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

Thread‑safe

Connection pool

Client SSL/TLS verification

Multipart file upload

Redirect handling

gzip/deflate support

HTTP and SOCKS proxy support

Although named urllib3, it is not a successor to urllib2; for direct use consider the requests library.

2. six

7.32 billion downloads – a compatibility library that lets code run on both Python 2 and Python 3. It provides helpers such as six.print_() to abstract syntax differences.

Name comes from 2 × 3 = 6

Related projects: future Use 2to3 to migrate to Python 3 only

3. botocore, boto3, s3transfer, awscli

Botocore (6.6 billion downloads) is the low‑level AWS SDK; boto3 (3.29 billion) builds on it to provide high‑level AWS services. s3transfer (5.84 billion) handles S3 transfers, and awscli (3.94 billion) is the AWS command‑line interface.

These packages illustrate the popularity of AWS services.

4. pip

6.27 billion downloads – the standard Python package installer. It can install packages from PyPI, private indexes, or local wheels, and works well with virtualenv to create isolated environments.

5. python-dateutil

6.17 billion downloads – extends the standard datetime module with powerful parsing and manipulation capabilities.

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

6. requests

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

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

7. certifi

5.52 billion downloads – provides a curated collection of root SSL certificates, enabling Python to verify HTTPS connections just like modern browsers.

8. idna

5.27 billion downloads – implements the Internationalized Domain Names in Applications (IDNA) protocol, converting Unicode domain names to ASCII (punycode) and back.

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

9. PyYAML

5.25 billion downloads – a YAML parser and emitter for Python, allowing easy reading and writing of YAML configuration files.

10. pyasn1

5.12 billion downloads – pure‑Python implementation of ASN.1 data structures and DER/BER/CER encoding, used in many security‑related protocols.

11. pyasn1-modules

5.12 billion downloads – provides ASN.1 modules for common standards such as X.509 certificates.

12. docutils

5.08 billion downloads – a modular system for converting plain text documents (reStructuredText) into formats like HTML, XML, and LaTeX. Used by the Python Enhancement Proposal (PEP) documentation and Sphinx.

13. chardet

5.01 billion downloads – detects the character encoding of text data, useful for processing unknown files or network streams.

chardetect somefile.txt
# output: ascii with confidence 1.0

14. rsa

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

import rsa
(bob_pub, bob_priv) = rsa.newkeys(512)
crypto = rsa.encrypt('hello Bob!'.encode(), bob_pub)
message = rsa.decrypt(crypto, bob_priv)
print(message.decode())  # hello Bob!

15. jmespath

4.73 billion downloads – provides a query language for extracting data from JSON structures.

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

16. setuptools

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

17. awscli

3.94 billion downloads – the official Amazon Web Services command‑line interface, built on botocore and boto3.

18. pytz

3.94 billion downloads – provides accurate and cross‑platform timezone definitions.

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

19. futures

3.89 billion downloads – backport of the concurrent.futures module for Python 2, enabling easy thread‑pool execution.

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

20. colorama

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

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')

21. simplejson

3.41 billion downloads – a fast JSON encoder/decoder, often faster than the built‑in json module because part of it is written in C.

22. boto3

3.29 billion downloads – the high‑level AWS SDK for Python, built on botocore.

Overall, the most popular packages provide core functionality such as HTTP communication, time handling, configuration parsing, encryption, and cloud service access, and many other libraries depend on them.