HTML instead of JSON (starts with <)

Fix HTML instead of JSON (starts with <). Validate strict JSON locally, pinpoint the exact break, then format/repair and re-validate (no upload).

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TL;DR: Validate locally, pinpoint the failing spot, apply the minimal fix, then validate again.

Fast no-upload workflow

  1. Validate the input (strict rules, correct encoding, correct delimiter/quotes).
  2. Locate the exact position/line reported by the parser or validator.
  3. Fix the smallest broken part (often a quote, escape, delimiter, or a truncated copy/paste).
  4. Re-validate and only then convert/export.

Recommended tools

Relevant guides

This list is auto-picked from existing guides. If you don’t see your exact case, use: search guides for “unexpected character html api returned html”.

Unexpected character encountered while parsing value: &lt;. Path '', line 0, position 0.: how to fix it (Newtonsoft.Json)

Newtonsoft.Json error (&lt;. , line 0, position 0.): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

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After parsing a value an unexpected character was encountered: }. Path '', line 1, position 2.: how to fix it (Newtonsoft.Json)

Newtonsoft.Json error (}. , line 1, position 2.): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

Unexpected character ('&lt;' (code 60)): expected a valid value (JSON String, Number, Array, Object or token 'null', 'true' or 'false'): how to fix it (Jackson)

Jackson JSON error (expected a valid value (JSON String, Number, Array, Objec...): why it happens (HTML/text instead of JSON, truncation) and the fastest fixes (no upload).

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System.Text.Json.JsonException: 'o' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.: what it means and how to fix it

Newtonsoft.Json error (&#039;o&#039; is an invalid start of a value. LineNumber: 0 | ByteP...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

System.Text.Json.JsonException: 'u' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.: what it means and how to fix it

Newtonsoft.Json error (&#039;u&#039; is an invalid start of a value. LineNumber: 0 | ByteP...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

System.Text.Json.JsonException: '&lt;' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.: what it means and how to fix it

Newtonsoft.Json error (&#039;&lt;&#039; is an invalid start of a value. LineNumber: 0 | ByteP...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

System.Text.Json.JsonException: 'N' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.: what it means and how to fix it

Newtonsoft.Json error (&#039;N&#039; is an invalid start of a value. LineNumber: 0 | ByteP...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

Invalid JSON primitive: ...: how to fix it (Newtonsoft.Json)

Newtonsoft.Json error (...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

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System.Text.Json.JsonException: ',' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.: what it means and how to fix it

Newtonsoft.Json error (&#039;,&#039; is an invalid start of a value. LineNumber: 0 | ByteP...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

System.Text.Json.JsonException: '/' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.: what it means and how to fix it

Newtonsoft.Json error (&#039;/&#039; is an invalid start of a value. LineNumber: 0 | ByteP...): common causes (HTML instead of JSON, extra chars) and a safe no-upload validation workflow.

Read guide

Search tools by keyword

Open tools search for “unexpected character html api returned html”.

Related subtopics

Related by intent

Expert signal

Expert note: HTML instead of JSON (starts with <) usually resolves fastest when triage starts from strict validation and then branches to comparison/alternative paths based on input quality.

Data snapshot 2026

MetricValue
Intent confidence score79/100
Predicted CTR uplift potential25%
Target crawl depth< 4 clicks

Trust note: All processing happens locally in your browser. Files are never uploaded.

FAQ (quick)

Start here: JSON Validator (runs locally, no upload).

Can I fix HTML instead of JSON (starts with <) without uploading my data? Yes. no-upload.ru tools run locally in your browser (NO UPLOAD). Start with JSON Validator and keep samples redacted if you must share them.

What is the fastest safe workflow? Validate first, fix the smallest broken part, then validate again before converting/exporting. This prevents silent downstream issues.

Why does HTML instead of JSON (starts with <) happen? Most issues come from copy/paste truncation, wrong encoding, non-strict syntax (comments/trailing commas), or a shape mismatch (array vs object).

Which tool should I start with for HTML instead of JSON (starts with <)? Start with JSON Validator. If you still see errors, follow the related playbook/trend report on this page.

Privacy & Security
All processing happens locally in your browser. Files are never uploaded.