invalid_request Authentication Origin: Application & API Last updated 14 Oct 2026

OAuth 2.0 Error: invalid_request (missing or invalid parameter)

The authorization or token request is malformed — a required parameter is missing, duplicated, or has an invalid value.

Exact message you may see Error 400: invalid_requestMissing required parameterThe request is missing a required parameter
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Seen on: REST API

Meaning

The error_description usually names the parameter: missing redirect_uri, client_id, code_verifier, invalid scope format, or duplicated parameters from bad URL building. Google shows “Error 400: invalid_request”.

Common causes

  • Required parameter missing (redirect_uri, client_id, code_challenge)
  • Parameter sent twice or badly encoded
  • PKCE required but not sent
  • Request violating provider policy (Google: insecure WebView/OOB flow)

⚡ Quick fix

  1. Read error_description for the parameter
  2. Log the full authorize/token request
  3. Compare with the provider’s documented parameters

Detailed fix by platform

Shell

  1. bash
    # decode the authorize URL you send
python3 -c "import sys,urllib.parse as u;print(u.parse_qs(u.urlparse(sys.argv[1]).query))" "$AUTH_URL"

How to diagnose

  1. Description — Named parameter
  2. Request — Full parameter list
  3. Policy — Provider requirements (PKCE, HTTPS)

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: Application & API. Errors that are often confused with or caused by this one (click to open):

400 — HTTP 400 Bad Request (HTTP)400additionalProperties — API Error: Request failed schema validation (must NOT have additional properties / Additional properties are not allowed) (API)additionalPropertiesauth/popup-closed-by-user — Firebase Auth: auth/popup-closed-by-user / auth/popup-blocked / auth/cancelled-popup-request (Authentication)auth/popup-closed-by-…auth/unauthorized-domain — Firebase Auth: auth/unauthorized-domain — This domain is not authorized for OAuth operations for your Firebase project (Authentication)auth/unauthorized-dom…bad_verification_code — GitHub OAuth: {"error":"bad_verification_code","error_description":"The code passed is incorrect or expired."} (Authentication)bad_verification_codedeleted_client — Google OAuth: Error 401: deleted_client — The OAuth client was deleted (Authentication)deleted_clientdisallowed_useragent — Google OAuth: Error 403: disallowed_useragent (sign-in from an embedded WebView) (Authentication)disallowed_useragentfile_type_not_allowed — Upload error: File type not allowed / unsupported file type (API)file_type_not_allowedinvalid_r…

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