Csv Diff API

POST https://api.findutils.com/api/tools/csv-diff/execute

Compare two CSV or TSV tables by key column and list the rows that were added, removed or changed - a table diff, not a line diff, so rows in a different order are not changes. keys names one or more columns (a composite key, e.g. email + country); when omitted the tool picks a shared column named id, else a unique *_id column (customer_id), else one named email, sku, uuid, key or code, else the first shared column whose values are unique in both files, else it falls back to whole-row comparison and says so in notes. A row is changed when a non-key column present in both files differs (cells compared exactly; trim and ignore_case apply to key matching only). Duplicate keys within a file keep the first row and are reported in duplicate_keys. A quote that opens and never closes stops the comparison with UNCLOSED_QUOTE naming the file and line. mode "row" compares whole rows as a multiset, with no changed class. Returns counts, the rows (capped at max_rows), and diff_csv: comma-separated, header change_type, then every column of A followed by the new columns of B, then old_<column> for each column that changed anywhere; removed rows hold A's values, added and changed rows B's, and old_<column> holds A's value on changed rows. diff_csv lists every added, removed and changed row; unchanged rows are left out. Nothing is uploaded when used on the browser page.

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Request body

application/json

a

string required

The old table (file A), CSV or TSV with a header row. a and b together up to about 10 MB.
b

string required

The new table (file B), CSV or TSV with a header row. a and b together up to about 10 MB.
keys

array optional

Key column names present in both files. Omit to let the tool suggest one.
mode

string optional

key (default): match rows by key columns. row: match whole rows, counting repeats. One of key · row. Default "key".
trim

boolean optional

Ignore spaces around key values when matching. Default true. Default true.
ignore_case

boolean optional

Match key values without regard to letter case. Default false. Default false.
delimiter

string optional

Field separator for both files. Default auto: detected per file from its first line. One of auto · , · · ; · |. Default "auto".
header

boolean optional

The first row of each file is a header. Default true. When false, columns are named column_1..N. Default true.
max_rows

integer optional

Most entries returned in rows. Default 5000. Counts and diff_csv are never cut. Default 5000.

Example arguments

Verified

{
  "a": "id,name,price\n1,Apple,1.00\n2,Banana,0.50",
  "b": "id,name,price\n1,Apple,1.20\n3,Cherry,3.00"
}

curl -X POST https://api.findutils.com/api/tools/csv-diff/execute \
  -H "Content-Type: application/json" \
  -d '{
    "a": "id,name,price\n1,Apple,1.00\n2,Banana,0.50",
    "b": "id,name,price\n1,Apple,1.20\n3,Cherry,3.00"
  }'

const response = await fetch('https://api.findutils.com/api/tools/csv-diff/execute', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({"a":"id,name,price\n1,Apple,1.00\n2,Banana,0.50","b":"id,name,price\n1,Apple,1.20\n3,Cherry,3.00"}),
});
const data = await response.json();

import requests

response = requests.post(
    "https://api.findutils.com/api/tools/csv-diff/execute",
    json={"a":"id,name,price\n1,Apple,1.00\n2,Banana,0.50","b":"id,name,price\n1,Apple,1.20\n3,Cherry,3.00"},
)
data = response.json()

$ch = curl_init('https://api.findutils.com/api/tools/csv-diff/execute');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
    CURLOPT_POSTFIELDS => '{"a":"id,name,price\n1,Apple,1.00\n2,Banana,0.50","b":"id,name,price\n1,Apple,1.20\n3,Cherry,3.00"}',
    CURLOPT_RETURNTRANSFER => true,
]);
$data = json_decode(curl_exec($ch), true);

Also an MCP tool

Call csv_diff from Claude, Cursor or any MCP client. Same arguments, same output.

https://mcp.findutils.com

MCP reference

Rate limit: 60 a minute, per IP
Auth: None
REST id: csv-diff
MCP name: csv_diff
Category: Data
Machine-readable: openapi.json · markdown.md

Request body

Example arguments

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