Valid controls
A baseline object and a Unicode case prove that the test harness can accept valid JSON.
Free reference asset · v1.0.0
JSON Error Fixture Pack
Use small, synthetic files to reproduce JSON parser, validator, editor, and ingestion behavior without exposing a production payload.
10 synthetic fixtures · CC0-1.0 · released July 20, 2026 · no account required
What is inside
Syntax failures and semantic traps in one small pack
Common syntax failures
Trailing commas, single quotes, unquoted keys, comments, invalid escapes, unexpected EOF, and leading zeros.
Semantic risk
The duplicate-key fixture parses in JavaScript but can silently overwrite an earlier value. Its category is explicit in the manifest.
Use the pack
Reproduce, classify, then verify
- Keep the versioned ZIP unchanged as the baseline.
- Run one fixture through your parser, editor, API, or ingestion job.
- Compare parse/no-parse behavior with manifest.json; treat exact error wording as engine-specific.