json_decode(): State mismatch (invalid or malformed JSON): what it means and how to fix it

TL;DR: Validate locally, fix the first real error, validate again (no upload).

Troubleshoot json_decode(): State mismatch (invalid or malformed JSON) quickly and validate JSON locally (no upload).

Guides by runtime PHP guides

What the error means

json_decode(): State mismatch (invalid or malformed JSON) means the parser expected valid JSON but encountered a character/token that cannot appear there. In practice, it usually means the input is not JSON (or not strict JSON), or it is incomplete.

Most common real-world causes

  • The input is not strict JSON (single quotes, comments, trailing commas).
  • The response is truncated (missing closing } / ] / ").
  • The response contains a prefix/suffix (logs, banners, debug output).
  • The payload has invalid escapes or control characters in strings.
  • You are parsing the wrong thing (already-parsed object, HTML, CSV, etc).

Fast debugging steps

  • Validate the JSON as-is to get an exact error location.
  • Check the first and last 50 characters for truncation and prefixes.
  • Fix one issue at a time and re-validate after each change.

Code example (php)

$obj = json_decode($text, true);
if (json_last_error() !== JSON_ERROR_NONE) {
  throw new Exception(json_last_error_msg());
}

Fix without uploading data

If the JSON contains sensitive data, validate and fix it locally. No Upload Tools runs 100% in your browser.

Workflow: validate -> fix the first error -> validate again -> export/convert.

FAQ

Does the exact token matter? Yes. The token often hints at the root cause: < is usually HTML, u is often undefined, and / often points to comments.

Should I just regex-fix JSON? Avoid blind regex edits. Validate after each change so you know what you fixed and what broke.

Next steps
Related by intent
json_last_error_msg(): State mismatch (invalid or malformed JSON): what it means and how json_decode(): Syntax error: what it means and how to fix it json_decode(): Recursion detected: what it means and how to fix it json_last_error_msg(): No error: what it means and how to fix it
Privacy & Security
All processing happens locally in your browser. Files are never uploaded.

Похожие материалы

Related by intent

Useful follow-up pages selected from real search impressions and no-click opportunities.

No-click fix: base64url decode phpNo-click fix: php json decode syntax errorNo-click fix: php json decode recursion detectedRelated fix: neighbor csharp php json decode state mismatch invalid or malformed json workflows enterprisRelated fix: neighbor csharp php json decode arg1 string int given workflows data importRelated fix: neighbor csharp php json decode arg1 string array given workflows data importRelated fix: neighbor csharp php json decode arg1 string float given workflows data importRelated fix: neighbor csharp php json decode expects string null given workflows data import

Next pages to check

Closest crawled pages without impressions yet. Added to speed first-impression conversion.

neighbor csharp php json decode state mismatch invalid or malformed json workflows enterneighbor csharp php json decode arg1 string array given workflows data importneighbor csharp php json decode arg1 string float given workflows data importneighbor csharp php json decode arg1 string int given workflows data importneighbor csharp php json decode expects string array given workflows data importneighbor csharp php json decode expects string array given workflows enterprise rolloutneighbor csharp php json decode expects string null given workflows data importneighbor csharp php json encode type is not supported workflows data importneighbor php go json cannot unmarshal array into field payload items type float64 troublneighbor php go json cannot unmarshal array into field payload items type int troubleshoneighbor php go json cannot unmarshal array into field payload user type string troublesneighbor php go json cannot unmarshal array into field user createdat type time time troneighbor php go json cannot unmarshal array into field user email type int64 troubleshooneighbor php go json cannot unmarshal array into field user id type float64 troubleshootneighbor php go json cannot unmarshal array into field user id type string troubleshootineighbor php go json cannot unmarshal bool into field meta count type bool troubleshootineighbor php go json cannot unmarshal bool into field meta count type int troubleshootinneighbor php go json cannot unmarshal bool into field meta count type int64 troubleshoot

Quick fix checklist

  • Reproduce the error on a minimal input.
  • Check type/format and field mapping.
  • Apply the smallest safe fix.
  • Validate on production-like payload.

Related by winning cluster

Linked from a winner family to push crawl and first-impression conversion.

Open cluster hubneighbor csharp php json decode state mismatch invalid or malformed json workflows enterprise rolloutneighbor csharp php json decode arg1 string array given workflows data importneighbor csharp php json decode arg1 string float given workflows data importneighbor csharp php json decode arg1 string int given workflows data importneighbor csharp php json decode expects string array given workflows data importneighbor csharp php json decode expects string array given workflows enterprise rolloutneighbor csharp php json decode expects string null given workflows data importneighbor csharp csharp newtonsoft error converting 123 system int64 items 0 id workflows api gateway