Convert CSV to JSONL (JSON Lines)

Online Converter: Convert CSV file to JSON Lines (NDJSON) format

Your CSV file

Conversion Configuration

CSV file delimiter

,Comma

;Semicolon

|Vertical Bar

→Tabulation (tab)

Use first line/row as a header?

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JSONL Converters CSV Converters

Convert CSV files to JSON Lines (JSONL/NDJSON) format for streaming applications, machine learning pipelines, and log processing systems. Each row becomes a separate JSON object on its own line, enabling efficient line-by-line processing.

JSONL is ideal for data pipelines where you need to process records individually without loading entire files into memory. Convert your tabular CSV data into this streaming-friendly format.

Why Convert CSV to JSONL?

Stream Processing: Process records one at a time without loading the entire dataset into memory.
ML Training Data: JSONL is the preferred format for OpenAI fine-tuning, Hugging Face datasets, and many ML frameworks.
Log Ingestion: Feed data into Elasticsearch, Splunk, or other log analysis systems that accept newline-delimited JSON.
Data Pipelines: Build robust ETL pipelines with clear record boundaries and easy error handling per line.

About JSON Lines Format

JSON Lines (JSONL, NDJSON) is a text format where each line is a valid JSON object. Unlike standard JSON arrays, JSONL files can be processed line by line, making them perfect for streaming and large datasets.

Format Resources

JSON Lines - Format specification
RFC 4180 - CSV format specification

Related Converters

JSONL to CSV - Convert back to CSV format
CSV to JSON - Convert to standard JSON array
CSV to Parquet - Convert to columnar format

Frequently Asked Questions

What's the difference between JSON and JSONL?

Standard JSON wraps all records in an array with commas between them. JSONL puts each record on its own line with no array wrapper, enabling line-by-line processing without parsing the entire file.

How are CSV headers handled?

CSV column headers become the keys in each JSON object. For example, a CSV with columns "name,email" produces JSONL records like {"name":"...","email":"..."}.

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