How to Completely Fix the 429 Too Many Requests Error? Implementing Exponential Backoff Retry
Do high-frequency prompt APIs suddenly return 429 and crash? This detailed tutorial teaches you how to write Exponential Backoff retry logic in Python/Node.js to gracefully handle traffic spikes.
1. What Triggers a 429 Error
HTTP 429 explicitly tells the client that the current request has already exceeded the configured RPM (requests per minute) or TPM threshold.
If you simply retry immediately in a tight loop when you receive a 429, it will only make the server reject you more aggressively.
2. Standard Exponential Backoff Retry Python Code
import time, random
def call_gemini_with_retry(prompt, max_retries=5):
for i in range(max_retries):
try:
return model.generate_content(prompt)
except Exception as e:
if "429" in str(e) and i < max_retries - 1:
sleep_time = (2 ** i) + random.uniform(0, 1)
time.sleep(sleep_time)
else:
raise e
By dynamically increasing the retry wait interval, you can smoothly absorb instantaneous burst traffic and bring the business call success rate up to 99.9%.