Data & Requests · LOCAL TOOL

CSV Mapping Preview

Select CSV columns using a JSON mapping array with from, to, and type fields. Convert to strings, finite numbers, or true/false booleans and report conversion failures by source row and column.

Runs in this page
No API call

WORKSPACEINPUT → RESULT

Your input

LOCAL

Result

Run the tool to see a result.

Your result will appear here. Input is not saved.

Browser-side processingNothing is sent to a tool API.

WHY THIS TOOL EXISTS

A focused job, not a black box.

The mapping is explicit and reviewable. Failed rows remain outside the converted record list, so an empty number or an unrecognized boolean cannot silently become a plausible value.

How to use it

Paste CSV with unique column headers.
Define each output field and its explicit type in the mapping array.
Inspect rejected cells and source row numbers before using converted records.

TRY A WORKING EXAMPLE

Start with known input.

Load this sample into the workspace, run the tool, and compare the result shown below.

Show sample input

{
  "csv": "name,count,active\nRin,12,true\nMika,unknown,false",
  "mapping": "[{\"from\":\"name\",\"to\":\"name\",\"type\":\"string\"},{\"from\":\"count\",\"to\":\"quantity\",\"type\":\"number\"},{\"from\":\"active\",\"to\":\"enabled\",\"type\":\"boolean\"}]"
}

Expected sample result from the local tool

1 row(s) converted · 1 failed cell(s).

{
  "converted": [
    {
      "sourceRow": 2,
      "record": {
        "name": "Rin",
        "quantity": 12,
        "enabled": true
      }
    }
  ],
  "failures": [
    {
      "row": 3,
      "column": "count",
      "value": "unknown",
      "expected": "number"
    }
  ]
}

Rows with any failed cell are excluded from the converted records; original row numbers remain available.

LIMITS AND INTERPRETATION

What the result cannot tell you.

At most 10000 rows and 100 mappings. Numbers use JavaScript Number conversion and precision; booleans accept only true/false, ignoring surrounding space and case. Rows with any failed conversion are excluded.

Inputs are processed in this page and are not written to local storage.