What problems have you encountered when integrating and interacting with external APIs or services?

When integrating with external APIs or services, the following issues often arise:

• Network instability and timeouts: the network may be slow or interrupted, leading to errors or long response wait times.
• Rate limiting: many APIs have limits on the number of requests per unit of time, requiring retry mechanisms or queues.
• API changes: external services may change data formats, endpoints, or logic, breaking the integration.
• Authentication and authorization errors: improper management of tokens or access keys leads to access denial.
• Error and exception handling: it is necessary to properly handle various error codes and exceptions so that the application does not crash.
• Serialization/deserialization issues: mismatched data formats (JSON, XML) or unexpected fields.

To address these issues, the following are typically used:

• Exponential backoff retries
• Caching responses
• Monitoring and logging requests
• API contract validation and testing

Example of handling a request with timeout and retries in Python:

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

session = requests.Session()
retry = Retry(total=3, backoff_factor=1, status_forcelist=[429, 500, 502, 503, 504])
session.mount('https://', HTTPAdapter(max_retries=retry))

try:
    response = session.get('https://api.example.com/data', timeout=5)
    response.raise_for_status()
    data = response.json()
except requests.exceptions.RequestException as e:
    print(f'Error during request: {e}')