Tiny retry decorator for Python, works for sync and async functions, with optional verbose output and callback hooks.

pip install retrymax

• Retry synchronous or asynchronous functions
• Optional exponential backoff
• Optional verbose output to see retry attempts
• Optional callback hook for custom actions on retry
• Safe handling of exceptions, only retries specified exceptions

from retrymax import retry

@retry(times=3, delay=1, verbose=True)
def fetch_data():
    print("Trying to fetch data...")
    raise ValueError("Failed!")

try:
    fetch_data()
except ValueError:
    print("All retries failed!")

Output:

Trying to fetch data...
[retrymax] Attempt 1 failed: Failed!
Trying to fetch data...
[retrymax] Attempt 2 failed: Failed!
Trying to fetch data...
[retrymax] Attempt 3 failed: Failed!
All retries failed!

import asyncio
from retrymax import retry

@retry(times=3, delay=0.5, verbose=True)
async def fetch_async():
    print("Trying async fetch...")
    raise ValueError("Async fail!")

async def main():
    try:
        await fetch_async()
    except ValueError:
        print("All async retries failed!")

asyncio.run(main())

Output:

Trying async fetch...
[retrymax] Attempt 1 failed: Async fail!
Trying async fetch...
[retrymax] Attempt 2 failed: Async fail!
Trying async fetch...
[retrymax] Attempt 3 failed: Async fail!
All async retries failed!

from retrymax import retry

def my_callback(exception, attempt):
    print(f"[callback] Retry {attempt} failed: {exception}")

@retry(times=3, delay=0.5, verbose=True, on_retry=my_callback)
def fetch_with_callback():
    print("Attempting fetch with callback...")
    raise ValueError("Failed again!")

try:
    fetch_with_callback()
except ValueError:
    print("All retries failed with callback!")

Output:

Attempting fetch with callback...
[retrymax] Attempt 1 failed: Failed again!
[callback] Retry 1 failed: Failed again!
Attempting fetch with callback...
[retrymax] Attempt 2 failed: Failed again!
[callback] Retry 2 failed: Failed again!
Attempting fetch with callback...
[retrymax] Attempt 3 failed: Failed again!
[callback] Retry 3 failed: Failed again!
All retries failed with callback!

• times (int): Number of retry attempts (default: 3)
• delay (float): Delay between retries in seconds (default: 0)
• backoff (str or None): "exp" for exponential backoff (default: None)
• exceptions (tuple): Exceptions to catch and retry (default: (Exception,))
• verbose (bool): Print retry attempts (default: False)
• on_retry (callable): Optional callback called on each retry with (exception, attempt)

MIT License

• Works with Python 3.8+
• Supports both synchronous and asynchronous functions
• Safe and consistent retry behavior
• Perfect for network calls, flaky APIs, or any operation that may fail intermittently