NDJSON → JSON Converter
Convert NDJSON to JSON Online
Merge NDJSON (newline-delimited JSON) streams into standard JSON arrays. Convert Buddy handles massive NDJSON log files with streaming processing that runs entirely in your browser. Perfect for log analysis, data aggregation, and API responses.
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Processes NDJSON line-by-line
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Merges into JSON arrays
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Handles log files of any size
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Validates each JSON line
Start Converting NDJSON to JSON
No registration required. Files processed locally in your browser.
Command Center
Detect → schema → convert
Drop a file and watch Convert Buddy detect structure, preview fields, and convert instantly.
Drop a file to detect + convert
Supported formats: CSV, JSON, NDJSON, XML
Detection status
IdleFormat: ndjson
Structure: Awaiting detection.
Fields: 0
Estimated records: —
Input: Awaiting file
Output format
Choose your destination format.
Performance telemetry
LiveThroughput
0.0 MB/s
Records/sec
0
Records processed
0
Elapsed
00:00
Bytes in/out
0.0 MB / 0.0 MB
Output
Output will appear here after conversion completes.
Format: ndjson → json
Output files are UTF-8 text. JSON output is intentionally minified for streaming performance, so it may open as a single line until you run your editor's format command.
Frequently Asked Questions
What is NDJSON?
NDJSON (Newline Delimited JSON) is a format where each line is a valid JSON object. It is commonly used for log files, streaming data, and large datasets because it can be processed line-by-line without loading the entire file into memory.
How is NDJSON different from JSON?
Standard JSON is a single data structure (object or array), while NDJSON is a sequence of JSON values separated by newlines. NDJSON is ideal for streaming and append-only logs, while JSON is better for structured documents. Convert Buddy can convert between both formats.
Can I convert large NDJSON files?
Yes. Convert Buddy parses NDJSON files line-by-line using streaming, so file size is not limited by browser memory. We have tested with multi-GB NDJSON log files. The output can be streamed as a JSON array or saved directly to disk.
What happens if an NDJSON line is invalid?
Convert Buddy validates each line as it is parsed. Invalid JSON lines are reported with details (line number and error message), and you can choose to skip invalid lines or halt conversion. This helps identify malformed log entries.
When should I use NDJSON instead of JSON?
Use NDJSON for streaming data, log files, and large datasets that need append-only writes. Use standard JSON for configuration files, API responses, and when you need a single hierarchical structure. Convert Buddy supports both directions.
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