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JSONL Deduplicator

Clean repeated JSONL records before validation, splitting or training. This browser-based deduplicator can compare whole records or a single key field, normalize whitespace and download a deduplicated JSONL file locally.

AI Prep

No file selected
Read locally in your browser only

This tool does not upload files to a server.

Deduplication options

No fields detected yet.

Total lines

0

Unique lines

0

Removed lines

0

Duplicate groups

0

Paste JSONL content to remove repeated AI dataset records.

Duplicate matches

Review which lines were removed and which earlier line they matched.

No duplicate matches yet.

What this tool does

JSONL Deduplicator removes repeated records from line-delimited datasets before they flow into training, evaluation or batch-processing pipelines. It can compare full records or a single selected field so you can choose whether duplicate detection should be strict or task-focused.

This is especially useful when data comes from merged exports, repeated collection jobs or iterative prompt-building workflows where near-identical records can quietly inflate the dataset.

  • Deduplicate by full normalized record or by one key field.
  • Normalize whitespace before matching repeated prompts and answers.
  • Inspect which lines were removed and which earlier lines they matched.

When to use it

Use deduplication before train/test splitting, JSONL validation or prompt dataset conversion if you suspect the source data was merged from multiple exports. Removing exact repeats early keeps later metrics and evaluation splits more trustworthy.

It is also useful after conversion workflows, where the schema may look clean but repeated content still remains underneath.

  • Run deduplication after merging multiple JSONL files.
  • Check for repeated prompts before model training.
  • Use a key field when the full record differs only in metadata.

How to use

  • Paste JSONL content or import a local `.jsonl` file.
  • Optionally enter a key field such as `prompt`, `id` or `instruction`, then choose normalization options.
  • Run deduplication to inspect duplicate groups and download the cleaned JSONL output.

Example

Input

{"prompt":"Summarize","completion":"Short"}
{"prompt":"Summarize","completion":"Short"}

Output

Total lines: 2 | Unique lines: 1 | Removed lines: 1

Privacy note

JSONL parsing and deduplication happen entirely in your browser. Imported files stay on your device and are not uploaded to QuickTinyData servers.

Recommended Guides

Start with these higher-value walkthroughs to understand the workflow around this tool, not just the button clicks.

FAQ

Can I deduplicate by prompt or ID instead of the full record?

Yes. Enter a key field name to compare just that value instead of the entire JSON object.

Does this detect semantic duplicates?

No. It removes exact duplicates after optional normalization, not meaning-level similarities.

Should I validate JSONL before or after deduplication?

If the file may contain malformed rows, validate first. If the syntax is already clean, deduplicating early is often a good next step.

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