specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: Amazon S3
providerId: amazon-s3
created: '2026-05-04'
# Provenance stamped 2026-08-11: this artifact was written by the API Evangelist
# bulk sweep dated 2026-05-04, not harvested from the provider. See roadmap#35.
method: generated
modified: '2026-05-05'
reconciled: true
tags:
  - Rate Limiting
  - AWS
  - Object Storage
  - S3
description: Amazon S3 enforces request limits at the partitioned-prefix level inside a bucket - 3,500
  PUT/COPY/POST/DELETE per second and 5,500 GET/HEAD per second per prefix - and scales nearly linearly
  by sharding across prefixes. Bucket-level operations (CreateBucket, DeleteBucket, etc.) follow the
  AWS API throttling envelope. Use exponential backoff with jitter on SlowDown (503) responses.
sources:
  - https://docs.aws.amazon.com/AmazonS3/latest/userguide/optimizing-performance.html
  - https://docs.aws.amazon.com/AmazonS3/latest/userguide/troubleshooting.html
  - https://docs.aws.amazon.com/general/latest/gr/api-retries.html
headers:
  requestId: x-amz-request-id
  retryAfter: Retry-After
responseCodes:
  throttled: 503
  quotaExceeded: 429
  serviceUnavailable: 503
limits:
  - name: PUT/COPY/POST/DELETE per prefix
    scope: bucket-prefix
    metric: requests_per_second
    limit: 3500
    timeFrame: second
    notes: Per partitioned prefix; shard across prefixes to scale linearly.
  - name: GET/HEAD per prefix
    scope: bucket-prefix
    metric: requests_per_second
    limit: 5500
    timeFrame: second
    notes: Per partitioned prefix.
  - name: Bucket count per account
    scope: account
    metric: count
    limit: 10000
    notes: Soft limit; raisable via Service Quotas (default ranges 100 to 10,000).
  - name: S3 Express One Zone directory bucket
    scope: bucket
    metric: requests_per_second
    limit: see S3 Express One Zone docs
    notes: Higher per-bucket limits (millions of requests/second) on Express One Zone.
policies:
  - name: Backoff on SlowDown
    description: SlowDown (HTTP 503) responses indicate prefix-level throttling. Retry with exponential
      backoff and jitter; AWS SDKs default to standard retry mode.
  - name: Prefix sharding
    description: For very high throughput, distribute keys across prefixes (e.g. random hash prefixes)
      to multiply throughput.
  - name: Multipart upload
    description: For files larger than 100 MB, use multipart upload (parallel parts) to reduce wall-clock
      time and benefit from prefix-level concurrency.
  - name: Quota increases
    description: Bucket-count, multipart upload, and bucket policy limits are soft and raisable via Service
      Quotas.
maintainers:
  - name: Kin Lane
    email: kin@apievangelist.com
    url: https://apievangelist.com
  - name: Amazon Web Services
    email: support@aws.amazon.com
    url: https://aws.amazon.com