When I make requests to my Amazon S3 bucket, I get a 503 Slow Down response. How can I avoid this request throttling from Amazon S3?

Last updated: 2019-12-16

I'm getting a 503 Slow Down response when I send requests to my Amazon Simple Storage Service (Amazon S3) bucket:

"AmazonS3Exception: Please reduce your request rate. (Service: Amazon S3; Status Code: 503; Error Code: SlowDown)"

How can I avoid request throttling from Amazon S3?

Resolution

You can send 3,500 PUT/COPY/POST/DELETE and 5,500 GET/HEAD requests per second per partitioned prefix in an S3 bucket. When you have an increased request rate to your bucket, Amazon S3 might return 503 Slow Down errors while it scales to support the request rate. This scaling process is called partitioning.

To avoid or minimize 503 Slow Down responses, verify that the number of unique prefixes in your bucket supports your required transactions per second (TPS). This helps your bucket leverage the scaling and partitioning capabilities of Amazon S3. Additionally, be sure that the objects and the requests for those objects are distributed evenly across the unique prefixes. For more information, see Best Practices Design Patterns: Optimizing Amazon S3 Performance.