Ndjson To Csv MCP tool

MCP findutils:ndjson_to_csv

Convert newline-delimited JSON (NDJSON, JSON Lines, .jsonl) into a flat CSV. Each line is one JSON object; the header is the union of every key in first-seen order, and a key a row does not have becomes an empty cell. Nested objects are flattened to dot paths (user.name) and array items to indexed keys (tags[0]) by default, or kept as JSON text in one cell with nested set to json. A line that is not valid JSON or not an object is skipped and reported by its line number; the other lines still convert. A JSON array is refused with a pointer to the JSON to CSV tool. Quoting follows RFC 4180. Values are written as text and never coerced.

Open the tool Try it

Arguments

application/json

ndjson

string required

The JSON Lines text: one JSON object per line.
nested

string optional

flatten (default): nested keys become dot paths such as user.name and array items become tags[0]. json: a nested value is written as JSON text in one cell. One of flatten · json. Default "flatten".
delimiter

string optional

Output field separator: "," (default), ";" or "\t". Default ",".
header

boolean optional

Write the header row. Default true. Default true.

Example arguments

Verified

{
  "ndjson": "{\"id\":1,\"user\":{\"name\":\"Ada\"}}\n{\"id\":2,\"user\":{\"name\":\"Linus\"},\"tags\":[\"a\"]}"
}

claude mcp add findutils --transport http https://mcp.findutils.com/

{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}

curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "ndjson_to_csv",
      "arguments": {
        "ndjson": "{\"id\":1,\"user\":{\"name\":\"Ada\"}}\n{\"id\":2,\"user\":{\"name\":\"Linus\"},\"tags\":[\"a\"]}"
      }
    }
  }'

Also a REST endpoint

The same tool answers plain HTTP at POST /api/tools/ndjson-to-csv/execute.

REST reference

Rate limit: 120 a minute, per IP
Auth: None
REST id: ndjson-to-csv
MCP name: ndjson_to_csv
Category: Data
Machine-readable: openapi.json · markdown.md

Arguments

Example arguments

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