NDJSON Viewer

Paste a newline-delimited JSON stream and read it — one indented record per block, minified, as a single JSON array, or as an aligned table. Search any key or value at any depth, filter by a dotted path, page through it, and see exactly which lines failed to parse. Nothing leaves your browser.

NDJSON / JSON Lines (one complete JSON value per line)Show the records asIndent (spaces, 0 minifies)Search any key or value, at any depthSearch matchesCase-sensitive matchingFilter by dotted path (numbers index arrays)…and require this value thereCompare search and value bySort every object's keys alphabeticallySkip this many matching recordsShow at most this many records (0 = all)Lines that are not valid JSONShow input line numbersPrepend a stats header (# comment lines)

Try:

Records

About this tool

NDJSON (also called JSON Lines) is the format many loggers, queues and export jobs use when they want one JSON record per line. It is friendly to streaming tools, but not friendly to eyeballs: one broken line can hide inside thousands of records, nested fields are hard to scan, and turning the stream into an array or a table usually means writing a one-off script.

This viewer keeps the streaming shape but makes it readable. Paste a stream and choose one of four views:

View	Use it when
Pretty	You want one indented record per block, with key order preserved.
Compact	You want valid NDJSON back, minified one record per line.
Array	A downstream tool accepts JSON arrays but not JSON Lines.
Table	Records are mostly objects and you want a quick column view.

Search walks every key and scalar value at any depth, so timeout finds err.code without you knowing the path. When you do know the path, use a dotted selector like user.name or items.0.id. Invalid lines are reported in place by default, with line and column, so you can fix the bad record without losing the rest of the stream.

Worked example

Paste this stream:

{"id":1,"status":"ok","latency_ms":12}
{"id":2,"status":"error","latency_ms":940,"err":{"code":"timeout"}}
{"id":3,"status":"ok","latency_ms":31}

Set Search any key or value to timeout, turn on Show input line numbers, and leave the view on Pretty. The result is only the matching record, with the original line number preserved:

# record 1 (line 2)
{
  "id": 2,
  "status": "error",
  "latency_ms": 940,
  "err": {
    "code": "timeout"
  }
}

Limits and edge cases

Up to 50,000 non-blank lines per run.
Every non-blank line must be one complete JSON value. Pretty-printed multi-line JSON is JSON, not NDJSON; use the array view after first converting it to one record per line.
Table view is a quick text table, not CSV. Nested objects and arrays are rendered as compact JSON inside a cell.
Search is text-based over keys and scalar values. For a boolean expression language or field projection, use a dedicated NDJSON filter tool instead.

FAQ

What is the difference between NDJSON and a JSON array?

NDJSON has one complete JSON value per line, with no comma between lines and no outer brackets. It is easy to append to and stream because a program can parse each line as soon as it arrives. A JSON array wraps all records in [ and ] with commas between them, which is what many web APIs and editors expect. The Array view turns the lines into that shape without changing the records.

Will one bad line make the whole stream fail?

Not by default. Lines that are not valid JSON is set to Report each one in place, so the viewer prints a # line N: invalid JSON marker and keeps rendering the other records. Switch it to Stop at the first one when you are validating a machine pipeline and want a non-zero failure instead, or Drop them silently when you are exploring a noisy capture.

How do dotted paths work?

A path segment walks an object key, and a numeric segment indexes an array. user.name reads the name key inside the user object. items.0.id reads the id key from the first item in the items array. If the path is present and the value box is empty, the path is an existence filter; if the value box is filled, that exact field is compared using the selected match mode.

Does table view flatten nested JSON?

No. The table unions top-level keys across the shown object records. If a cell is a nested object or array, that nested value is printed as compact JSON inside the cell. That keeps the table faithful and predictable; deep flattening needs choices about separators, arrays and duplicate keys that are better handled by a converter built for tabular output.

Developer & Automation Access

Run it from the terminal

Same engine as this page, headless — via the gizza CLI:

gizza tool ndjson-viewer '{"id":1,"status":"ok","latency_ms":12}
{"id":2,"status":"error","latency_ms":940,"err":{"code":"timeout"}}
{"id":3,"status":"ok","latency_ms":31}'

New to the CLI? Get gizza →

Open it by URL

Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:

https://gizza.ai/tools/ndjson-viewer/?data=%7B%22id%22%3A1%2C%22status%22%3A%22ok%22%2C%22latency_ms%22%3A12%7D%0A%7B%22id%22%3A2%2C%22status%22%3A%22error%22%2C%22latency_ms%22%3A940%2C%22err%22%3A%7B%22code%22%3A%22timeout%22%7D%7D%0A%7B%22id%22%3A3%2C%22status%22%3A%22ok%22%2C%22latency_ms%22%3A31%7D&view=pretty&indent=2&search=timeout&search_in=any&case_sensitive=true&path=err.code&value=error&match_mode=contains&sort_keys=true&skip=0&limit=0&invalid=report&line_numbers=true&stats=true

Machine-readable descriptor: tool.json — title + parameters JSON Schema for agents.