InvalidRequest
AWS InvalidRequest (Invalid Request) means the request is not valid for the selected S3 operation, endpoint mode, or signature configuration. In Amazon S3, this error returns HTTP 400.
Last reviewed: March 29, 2026|Editorial standard: source-backed technical guidance
What Does Invalid Request Mean?
When InvalidRequest is returned, S3 received the request but rejected it as semantically incompatible with the selected operation or endpoint mode, so workflows fail until request semantics match bucket and API context.
Common Causes
- -Headers, endpoint style, or operation options are incompatible with the targeted S3 API path.
- -Request uses unsupported combination of bucket configuration and requested operation.
- -Signature/auth mode does not match what the endpoint or feature requires.
- -Client sends condition/precondition parameters that conflict with current object or bucket state.
How to Fix Invalid Request
- 1Rebuild request using SDK defaults for the specific S3 operation and endpoint type.
- 2Validate required headers and feature flags for the chosen bucket and API action.
- 3Remove conflicting optional parameters and reintroduce them one at a time.
- 4Confirm signing mode and region endpoint align with the target bucket configuration.
Step-by-Step Diagnosis for Invalid Request
- 1Capture full request headers, endpoint URL, and request ID from the failing call.
- 2Compare failing request against AWS SDK-generated request for the same operation.
- 3Inspect bucket settings (region, acceleration, ownership controls, versioning) for incompatibilities.
- 4Trace middleware/proxy behavior that may rewrite headers or host style.
Operation Compatibility Checks
- -Inspect whether requested options are valid for the specific S3 operation (example: selected headers or flags are valid for one API call but invalid for another).
- -Verify bucket feature state against request intent (example: operation assumes a bucket setting that is not enabled for that bucket context).
Endpoint and Signature Mode Audit
- -Trace endpoint style and region targeting choices (example: host style or region mismatch makes an otherwise valid request semantically invalid).
- -Inspect signed headers and middleware rewrites on the wire (example: proxy modifies request characteristics after signing, causing InvalidRequest in specific S3 flows).
How to Verify the Fix
- -Replay the same operation and confirm InvalidRequest is no longer returned.
- -Validate object/bucket operation outcomes match functional expectations.
- -Run regression suite across endpoint modes and feature combinations.
How to Prevent Recurrence
- -Use operation-specific request builders that enforce compatible header/option sets.
- -Test critical S3 workflows against real buckets in CI with feature parity to production.
- -Monitor InvalidRequest rates by operation and endpoint mode.
Pro Tip
- -capture and diff canonical request metadata for failing versus successful calls to isolate subtle endpoint-mode incompatibilities quickly.
Decision Support
Compare Guide
HTTP 400 vs 422: Bad Request vs Unprocessable Content
Fix API payload issues faster by using 400 for malformed syntax and 422 for semantic validation failures, so clients correct format before business rules.
Playbook
CORS Error Fix Playbook (Preflight / Origin / Credentials)
Use this playbook to separate browser-enforced cross-origin policy failures from server-side CORS header and route defects and apply strict origin and credential controls safely.
Playbook
Validation Failure Playbook (400 / 422 / INVALID_ARGUMENT)
Use this playbook to separate malformed-request failures from semantic validation failures, then fix request contracts without broad server-side bypasses.
Official References
Provider Context
This guidance is specific to AWS services. Always validate implementation details against official provider documentation before deploying to production.