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Requests — Python HTTP Client

Standard synchronous HTTP client for Python. Simple API, connection pooling, auth, retries.

For async or HTTP/2, use httpx — same API style, adds async/await and multiplexing.

When to Use What

Library Best for
requests Scripts, CLI tools, sync apps, low-concurrency API calls
httpx FastAPI test clients, async apps, HTTP/2, high-concurrency
aiohttp Async-first apps, WebSocket clients, custom event loops

Section Map

File Topics
01 Fundamentals & Methods GET/POST/PUT/PATCH/DELETE, params, headers, cookies, sessions, response
02 Advanced Patterns Auth, retries, timeouts, streaming, uploads, proxies, error handling

Cheat Sheet

HTTP Methods

Method Code Use case
GET requests.get(url, params={"q": "test"}) Read / search
POST requests.post(url, json={"name": "a"}) Create
PUT requests.put(url, json=data) Full replace
PATCH requests.patch(url, json=partial) Partial update
DELETE requests.delete(url) Remove
HEAD requests.head(url) Headers only

Response Object

Attribute Returns
r.status_code 200, 404, 500
r.ok True if status < 400
r.json() Parsed JSON -> dict / list
r.text Body as str (decoded)
r.content Body as bytes (raw)
r.headers Response headers (case-insensitive dict)
r.url Final URL after redirects
r.elapsed timedelta of round-trip time
r.raise_for_status() Raises HTTPError if 4xx/5xx

Session (Connection Pooling)

import requests

# Session reuses TCP connection and shares headers across calls
with requests.Session() as s:
    s.headers.update({"Authorization": "Bearer TOKEN"})
    r = s.get("https://api.example.com/users", timeout=(3.05, 10))
    r.raise_for_status()

Timeout + Retry

from urllib3.util.retry import Retry
from requests.adapters import HTTPAdapter

# retry on transient server errors with exponential backoff
retry = Retry(total=3, backoff_factor=0.5, status_forcelist=[502, 503, 504])
adapter = HTTPAdapter(max_retries=retry)

with requests.Session() as s:
    s.mount("https://", adapter)  # attach retry logic to all HTTPS calls
    s.mount("http://", adapter)
    r = s.get("https://api.example.com/data", timeout=(3.05, 10))

Auth

from requests.auth import HTTPBasicAuth

# basic auth — two equivalent forms
requests.get(url, auth=HTTPBasicAuth("user", "pass"), timeout=(3.05, 10))
requests.get(url, auth=("user", "pass"), timeout=(3.05, 10))  # shortcut

# bearer token via header
requests.get(url, headers={"Authorization": "Bearer TOKEN"}, timeout=(3.05, 10))

File Upload

# always open in binary mode ("rb") for uploads
with open("report.pdf", "rb") as f:
    requests.post(url, files={"file": ("report.pdf", f, "application/pdf")}, timeout=(3.05, 30))

Quick Rules

  1. Always set timeout — timeout=(connect, read) prevents hangs.
  2. Use Session for multiple calls to the same host — reuses TCP connections.
  3. Use json= instead of data=json.dumps(...) — auto-sets Content-Type.
  4. Call r.raise_for_status() — fail fast instead of silent 4xx/5xx.
  5. Use Retry adapter — transient 502/503/504 happen; retry with backoff.
  6. Stream large responses — stream=True + iter_content() to avoid OOM.
  7. Never verify=False in production — security risk.

See also