InvalidAction
AWS InvalidAction (Invalid Action) means the action or operation requested is invalid. In AWS APIs, this error returns HTTP 400.
Last reviewed: February 25, 2026|Editorial standard: source-backed technical guidance
What Does Invalid Action Mean?
When InvalidAction is returned, the request reaches AWS but the requested operation token is not recognized for that endpoint, so execution stops before business logic runs.
Common Causes
- -The
Actionvalue is misspelled or not supported by the targeted AWS service API. - -Request is sent to the wrong service endpoint, so valid action name is unknown there.
- -Client references deprecated/unsupported API version or action mapping.
- -Manual query construction strips or rewrites the action parameter unexpectedly.
How to Fix Invalid Action
- 1Verify action name against the exact service API reference for the chosen endpoint.
- 2Use official SDK/CLI command mappings instead of hard-coded action strings.
- 3Confirm request is routed to the intended AWS service and region endpoint.
- 4Regenerate signed request after correcting action and version parameters.
Step-by-Step Diagnosis for Invalid Action
- 1Capture full query string, endpoint host, and request ID from the failing request.
- 2Diff failing action/version pair against a known-good SDK-generated request.
- 3Inspect proxy/gateway transformations that may alter query parameters.
- 4Validate service discovery/routing config used by the caller.
Action Resolution Checks
- -Verify the
Actionvalue against the target service API and version (example: action string valid in one AWS API family is invalid on another endpoint). - -Inspect service endpoint routing and hostname selection (example: request is sent to a different service domain where the action token is unknown).
Query Construction Audit
- -Parse final query string immediately before signing and send (example: middleware rewrites or strips the
Actionparameter after request assembly). - -Trace API-version mappings in custom clients (example: deprecated action alias remains in legacy script while SDK mapping moved to a new operation).
How to Verify the Fix
- -Replay the same call and confirm InvalidAction is no longer returned.
- -Confirm intended operation executes and returns expected response schema.
- -Run regression tests for action routing and query construction paths.
How to Prevent Recurrence
- -Centralize action-to-endpoint mappings in versioned client libraries.
- -Ban raw action strings in application code where SDK operations exist.
- -Alert on InvalidAction spikes by service, endpoint, and deploy version.
Pro Tip
- -keep an allowlist of supported action names per service/version in CI and fail builds when unknown action tokens are introduced.
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.