Top Downloaded Python Packages on PyPI in the Past Year and Their Uses

Today we share the Python packages with the highest download counts on PyPI in the past year, discussing their functions, relationships, and reasons for popularity.

1. urllib3 (8.93 billion downloads) – A powerful HTTP client offering thread safety, connection pooling, SSL/TLS verification, multipart file upload, request retries, gzip/deflate support, and proxy handling. Although not a successor to urllib2, it underpins many other packages; for end‑users, requests is often preferred.

2. six (7.32 billion downloads) – Provides compatibility utilities for writing code that runs on both Python 2 and Python 3, masking syntax differences such as the print function. The name comes from 2 × 3 = 6; alternatives include future , and tools like 2to3 help migrate to Python 3.

3. botocore, boto3, s3transfer, awscli – These AWS‑related libraries rank among the top downloads. botocore is the low‑level core used by boto3 , which provides access to services like S3 and EC2. s3transfer manages S3 transfers, while awscli is the command‑line interface built on them.

4. pip (6.27 billion downloads) – The standard Python package installer, allowing simple commands such as pip install <package> and pip uninstall <package> . It works with requirements.txt and virtual environments to create isolated environments.

5. python-dateutil (6.17 billion downloads) – Extends the standard datetime module with powerful parsing capabilities. Example usage:

<code>from dateutil.parser import parse
logline = "2020-01-01T00:00:01 INFO 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 urllib3 . Example:

<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 (5.84 billion downloads) – Handles S3 data transfers; many projects depend on it, so its version stability is important.

8. certifi (5.52 billion downloads) – Provides a curated collection of root SSL certificates for Python, mirroring those used by browsers, enabling secure HTTPS verification.

9. idna (5.27 billion downloads) – Implements the Internationalised Domain Names in Applications (IDNA) protocol, offering idna.encode() and idna.decode() functions. Example:

<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) – A YAML parser and emitter for Python, allowing reading and writing of YAML files with native data types, surpassing ConfigParser capabilities.

11. pyasn1 (5.12 billion downloads) – Pure‑Python implementation of ASN.1 types and DER/BER/CER encoding, foundational for many security protocols and certificates.

12. docutils (5.08 billion downloads) – Converts plain text (reStructuredText) into formats like HTML, XML, and LaTeX; used by PEP documentation and Sphinx.

13. chardet (5.01 billion downloads) – Detects character encodings of byte streams. Command‑line usage:

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

14. rsa (4.92 billion downloads) – Pure‑Python RSA implementation supporting encryption, decryption, signing, and verification. 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>

15. jmespath (4.73 billion downloads) – Enables declarative extraction of data from JSON structures. Example:

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

These packages illustrate the diverse tools available in the Python ecosystem, their widespread adoption, and how they interoperate to simplify development tasks.