In order to deliver reliable services to AdWords API users across the globe, we use a Token Bucket algorithm to meter requests and determine the queries per second (QPS) rate. This is intended to prevent malicious or out-of-control software from overwhelming the AdWords API servers and affecting other users.

We recognize that your AdWords API client application may sometimes exceed the limit and receive a RateExceededError due to factors not fully in your control. Don’t worry. RateExceededError is usually transient and automatically resolved after 30 seconds of inactivity.

Rate limits fluctuate based on different variables, including server load. So we don’t recommend a fixed QPS limit to developers. That’s why it’s extremely important to understand how to handle RateExceededError, and develop your software with rate limits in mind.

Please take a look at our detailed AdWords API Rate Limit guide to learn more about:

• Different types of rate limits and rate limit scopes
• Operational limits for different account access levels
• Recommended practices to avoid exceeding different rate limits
• Tips for handling RateExceededError gracefully in your application, if it happens - Ray Tsang, AdWords API Team