NDJSON Tools
19 free NDJSON tools. All run in your browser, with no uploads and no account.
Convert NDJSON to another format
NDJSON to CSV
Convert NDJSON files to CSV format directly in your browser. No upload required — your data never leaves your device.
NDJSON to Parquet
Convert NDJSON files to Parquet format directly in your browser. No upload required — your data never leaves your device.
NDJSON to JSON
Convert NDJSON files to JSON format directly in your browser. No upload required — your data never leaves your device.
NDJSON to TSV
Convert NDJSON files to TSV format directly in your browser. No upload required — your data never leaves your device.
NDJSON to Arrow
Convert NDJSON files to Arrow format directly in your browser. No upload required — your data never leaves your device.
NDJSON to Excel
Convert NDJSON files to Excel format directly in your browser. No upload required — your data never leaves your device.
NDJSON to YAML
Convert NDJSON files to YAML directly in your browser. Download clean, human-readable YAML — no upload required.
NDJSON to XML
Convert NDJSON files to XML directly in your browser. Download a structured XML document with one element per row — no upload required.
NDJSON to SQL
Convert NDJSON files to SQL INSERT statements directly in your browser. Copy or download the generated SQL — no upload required.
NDJSON to Markdown
Convert NDJSON files to a Markdown table directly in your browser. Copy the output and paste it into any Markdown document.
NDJSON to HTML
Convert NDJSON files to an HTML table directly in your browser. Copy the markup or download a ready-to-use HTML file.
Convert other formats to NDJSON
CSV to NDJSON
Convert CSV files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
Parquet to NDJSON
Convert Parquet files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
JSON to NDJSON
Convert JSON files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
TSV to NDJSON
Convert TSV files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
Arrow to NDJSON
Convert Arrow files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
Excel to NDJSON
Convert Excel files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
YAML to NDJSON
Convert YAML files to NDJSON format directly in your browser. No upload required — your data never leaves your device.
View, inspect and query NDJSON files
NDJSON Viewer Online
View and inspect NDJSON files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.
SQL Query Tool
Load one or more files and query them with SQL. Each file becomes a table.
Data Profiler
Column-level stats: null rates, distinct counts, min, max and mean.
NDJSON Format Comparisons
NDJSON vs CSV
NDJSON stores one JSON object per line, ideal for streaming and logs. CSV is the universal flat-file format for spreadsheets and databases. Compare the trade-offs.
JSON vs NDJSON
JSON stores a single document; NDJSON stores one JSON object per line for streaming and large datasets. Learn when to use each and how to convert between them.
About NDJSON
NDJSON (Newline-Delimited JSON), also known as JSON Lines, stores one JSON object per line in a plain-text file. Each line is an independent, self-contained JSON document with no outer array wrapper. This structure makes NDJSON ideal for streaming, appending records incrementally, and processing large datasets without loading the entire file into memory — you can pipe an NDJSON file through any line-by-line processor.
Data engineers building event-driven systems and developers working with log aggregation use NDJSON constantly. Elasticsearch's bulk API accepts NDJSON; Logstash, Filebeat, and Fluentd emit NDJSON. Many application frameworks (Pino, Bunyan, Loguru) write structured logs as NDJSON. BigQuery streaming inserts and Kinesis Firehose delivery files also use the format. If you have ever tailed an application log and seen one JSON object per line, that is NDJSON.
NDJSON is not directly usable in spreadsheets or most analytics tools without conversion. If records contain deeply nested objects, flattening them before analysis is an extra step. Our NDJSON tools bridge the gap: convert to CSV or Parquet for loading into a data warehouse, flatten nested structures to a tabular form, or preview the schema and first rows directly in your browser without writing a script.
Frequently Asked Questions
What is the difference between NDJSON and regular JSON?
Regular JSON wraps multiple records in a single outer array: [{...}, {...}, ...]. NDJSON writes each record on its own line with no outer wrapper. The line-per-record structure means you can process an NDJSON file with simple line-by-line tools, append new records without parsing and rewriting the entire file, and stream records without buffering.
Can I convert NDJSON to CSV?
Yes — use the NDJSON to CSV converter. Each line becomes a row in the CSV output. Nested objects do not convert cleanly to CSV cells, so run the file through Flatten NDJSON first. Each nested key then becomes its own column before you convert.
How do I query an NDJSON file with SQL?
The SQL Query tool loads NDJSON files as DuckDB tables. DuckDB treats each line as a row and infers column types from the JSON values. You can run any SQL query — SELECT, GROUP BY, WHERE, JOIN — against the file directly. For nested fields, use json_extract() to pull values from nested objects.
What is the file extension for NDJSON?
Common extensions include .ndjson, .jsonl (JSON Lines), and .json. The format is identical regardless of extension — one JSON object per line. When uploading here, files with any of these extensions are recognised and parsed correctly.
More NDJSON operations
Every CSV operation also works directly on NDJSON files:
Remove duplicates · Filter · Sort · Split · Sample · Select columns · Rename · Merge · Trim · Fill empty values · Transpose · First N rows · Last N rows · Add row numbers · Validate structure · Flatten · Count by value · Unique values · Compare · Format timestamps · Find & replace · Split column · Combine columns · Convert case · Aggregate · Round numbers · Conditional column · Regex extract · Parse dates · Compare schemas · Change column types · Unpivot · Convert encoding · Shuffle · Bin column · Calculated column · Extract JSON column · Date difference · Normalize · Rank · Running total · Detect outliers · Validate emails · Moving average · Search text · Top N per group · Percent of total · Parse URLs · Lag / lead · Filter by date range · Correlation matrix · Fuzzy deduplicate · Hash columns · Group concatenate · Truncate dates · Coalesce columns · Add UUID column · Pad column · Percentile · Arg max / min