jsonl
What is a .jsonl file?
application/x-ndjson
JSONL (JSON Lines) is a text format where each line is a complete, independent JSON value, allowing records to be streamed and appended without parsing the whole file. It is not itself a JSON array and each line must stand alone. It is common in logging, machine learning datasets, and data pipelines.
How to use a .jsonl file
Use an example JSONL to test line-by-line streaming parsers, append-and-resume ingestion, and batch pipelines that process one record per line.
Download example .jsonl files
- JSON Lines (JSONL)A JSON Lines file with one object per line — for testing streaming/newline-delimited JSON parsers.
- JSON-Lines Application LogA structured application log with one JSON object per line at info/debug/warn/error levels — for testing log ingestion.
- Time-series — Sparse Events (JSONL)Sparse event log in JSON Lines — two events hours apart for event-stream ingestion tests.
- GDPR Activity Log (JSONL, SAMPLE)SAMPLE activity JSONL for subject-access export pipelines.
- Sentiment Classification Dataset (JSONL)A labelled sentiment-classification dataset in JSON Lines — 24 short product-review-style sentences balanced across positive, negative, and neutral. Fully synthetic; a fixture for testing text-classification loaders, tokenizers, and JSONL parsers.
- Named-Entity Recognition Dataset — BIO Tags (JSONL)A token-classification dataset in JSON Lines — 16 tokenized sentences with aligned BIO tags for person, organisation, and location entities. All names, companies, and places are fictional. A fixture for NER model training and sequence-labelling tooling.
- Chat Fine-tuning Dataset — OpenAI Format (JSONL)A chat fine-tuning dataset in the OpenAI JSONL format — one conversation per line as a messages array with system, user, and assistant turns. Synthetic Q&A content. Paired with an Anthropic-format twin for testing format converters.
- Chat Fine-tuning Dataset — Anthropic Format (JSONL)The same synthetic conversations in the Anthropic Messages JSONL shape — a top-level system prompt plus a messages array of user and assistant turns. The format twin of the OpenAI file, for testing chat-format conversion.
and 58 more in the library.