Doccano import failed error "JSONL file contains invalid record at line 12"

Not specified by the original author.

TL;DR

Fix this in Doccano by acting on the exact message first: open the file at line 12, fix the malformed JSON on that line (unescaped quotes inside the text field are the usual cause), validate that every line parses on its own, then reimport. Do not rerun the whole job unchanged, because the same inputs produce the same failure. Prove the fix on one item, then rerun the full scope and reconcile the counts.

JSONL file contains invalid record at line 12

Use this when

• The operation in Doccano fails with this exact message: JSONL file contains invalid record at line 12.
• The same failure repeats on retry with unchanged inputs.
• A review, export or check is blocked until this item completes.

Not for this skill when

• The message is a permission or outage notice from the platform. Resolve that first, then return here if this error remains.
• The operation completes and you only disagree with its output. That is a quality review, not this failure.

Steps

1. Reproduce the failure with the smallest scope that still shows it in Doccano, and copy the full message plus the item, user or metric involved into the run notes. Verify: the error is reproduced on demand with a named item, not only seen in a log.
2. Apply the specific fix for this error: open the file at line 12, fix the malformed JSON on that line (unescaped quotes inside the text field are the usual cause), validate that every line parses on its own, then reimport. Verify: every line parses independently and the import count matches the line count.
3. Check the neighbouring items that share the same config, ontology, baseline or credential, because this class of failure rarely affects only one item. Verify: the neighbouring items are listed and each is marked affected or clear.
4. Rerun the original operation in Doccano on the previously failing scope, watching for the same message rather than assuming success from a quiet log. Verify: the operation completes and the original message does not appear.
5. Compare the result counts, decisions or alerts against the source in Doccano so a silent partial success is caught before sign off. Verify: counts match the source or every difference is named and explained.
6. Record the fix, the triggering input and the verification result on the item so the next occurrence is recognised immediately. Verify: the record names the error, the fix applied and the evidence of success.

Why it happens

JSONL needs one complete JSON object per line; one broken line aborts the import at that line.

Variant phrasings

JSONL file contains invalid record at line 12

The verbatim form searchers paste from the terminal or console. Treat it identically: same fix, same single item proof, then the full rerun.

How to fix: Doccano import failed error "JSONL file contains invalid record at line 12"

The how-to phrasing for the same failure in Doccano. The steps above apply unchanged; start at the reproduction step rather than skipping to the rerun.

Doccano troubleshooting for this failure

The symptom-first phrasing used when the console hides the full message. Surface the full message first, confirm it matches the code block above, then follow the steps.

Compatibility: Doccano at current versions, plus the platform API or console the query names; no extra tooling beyond a text editor and the source system access needed to verify counts.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstn9Zot1xAwzFlV6itLznqg

Resolved from the public thread: https://vectle.com/posts/pstn9Zot1xAwzFlV6itLznqg

Thread query: Doccano import failed error "JSONL file contains invalid record at line 12"

TL;DR: Fix this in Doccano by acting on the exact message first: open the file at line 12, fix the malformed JSON on that line (unescaped quotes inside the text field are the usual cause), validate that every line parses on its own, then reimport. Do not rerun the whole job unchanged, because the same inputs produce the same failure. Prove the fix on one item, then rerun the full scope and reconcile the counts.