How much does a csv-to-json call cost?

$0.005 per call, paid in USDC on Base via x402, with no account and no API key.

What does csv-to-json return?

A JSON object with 6 top-level fields: source_url, delimiter, columns, rows, row_count and truncated. The example on this page is a real call over documents/garden-plots.csv.

What happens when a csv-to-json call fails?

The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled. A 503 upstream_unavailable can follow a settled call; the x402 payments guide covers it, 429, 402 and an uncertain 500.

catalogue / tools / Documents / CSV to JSON API

CSV to JSON API

Parses a CSV/TSV document into JSON rows, keyed by a header row or as arrays; the delimiter is auto-detected.

Endpoint: POST /v1/csv-to-json
Price: $0.005 per call
Family: Documents
Docs: /docs/csv-to-json

01When to use it

A correct CSV parser is more than a split on commas (quoted fields, embedded newlines and escaped quotes all bite), and doing it over a URL an agent fetches itself walks past every SSRF control.
Your source is CSV or TSV and you need JSON.

When not to use it

The input is over 25 MB (26,214,400 bytes): csv-to-json answers too_large (413).
The destination needs more than 30 s to answer: the call ends with upstream_timeout (424).
The destination is on a private or local network: the network guard refuses it with blocked_target (403).

02Parameters

Field	Type	Required	Description
url	string	yes	UTF-8 CSV/TSV URL. Missing charset means UTF-8; only utf-8 and utf8 declarations are accepted (case-insensitive, optionally quoted). Unsupported or invalid declarations and NUL bytes return 415; malformed UTF-8 returns 422. A UTF-8 BOM is accepted. Encoding is checked across the whole body.
delimiter	string	no	A single field delimiter character such as "," or a tab; omitted, it is auto-detected from the first rows among comma, tab, pipe, semicolon and the ASCII record and unit separators, and a line break, quote or BOM given here falls back to a comma.
header	boolean	no	Use the first nonempty record as object keys. Names are trimmed; blank names become column_<position>. Names are made unique left to right using the next unused _2, _3 suffix, including collisions with literal suffixed names. Special names remain data keys. Short rows pad with empty strings; extra fields return 422 csv_extra_fields. With false, preserve actual row widths as string arrays. Default: true.
max_rows	integer	no	Maximum returned nonempty data rows. One additional nonempty record sets truncated; its width is budgeted but not checked against the header. A truncated success does not validate the entire CSV structure. Default: 10000.

03Limits

Limit	Value
Largest source file	25 MB (26,214,400 bytes)
Timeout	30 s
Source formats	CSV, TSV
Output formats	JSON

04Example

The published example of csv-to-json, verbatim: the request body and the response it returns.

Request

POST /v1/csv-to-json
content-type: application/json
payment-signature: <base64 x402 payload>

{
  "url": "https://grist.tools/samples/documents/garden-plots.csv",
  "header": true
}

Response

200 OK
payment-response: <base64 settlement receipt>

{
  "source_url": "https://grist.tools/samples/documents/garden-plots.csv",
  "delimiter": ",",
  "columns": [
    "plot",
    "holder",
    "crop",
    "area_m2",
    "notes"
  ],
  "rows": [
    {
      "plot": "A1",
      "holder": "Maple Group",
      "crop": "tomatoes",
      "area_m2": "12",
      "notes": "Stakes needed, north side"
    },
    {
      "plot": "A2",
      "holder": "Oak Group",
      "crop": "beans",
      "area_m2": "08",
      "notes": ""
    },
    {
      "plot": "B1",
      "holder": "Willow Group",
      "crop": "herbs, mixed",
      "area_m2": "6",
      "notes": "Shares water with \"B2\""
    },
    {
      "plot": "B2",
      "holder": "Birch Group",
      "crop": "squash",
      "area_m2": "10.50",
      "notes": "Compost added in April"
    }
  ],
  "row_count": 4,
  "truncated": false
}

Sample file: documents/garden-plots.csv. Five-line comma-separated table of garden plots with a header row, quoted fields holding commas and doubled quotes, an empty field and number-like values such as 08 and 10.50.

Response field	Type	In the example
source_url	string	"https://grist.tools/samples/documents/garden-plots.csv"
delimiter	string	","
columns	array	5 items
rows	array	4 items, each with plot, holder, crop, area_m2 and notes
row_count	number	4
truncated	boolean	false

05Call it from code

JavaScript

// csv-to-json: $0.005 per call, paid in USD Coin on eip155:8453 via x402
// Install: npm install @x402/fetch@2 @x402/evm@2 viem@2
// Save as client.mjs (ES module, Node 18+), export EVM_PRIVATE_KEY with the paying wallet's key in your shell, then run: node client.mjs
// The wrapper reads the 402 (payment-required), signs and retries with payment-signature.
import { wrapFetchWithPayment, x402Client, decodePaymentResponseHeader } from '@x402/fetch'
import { ExactEvmScheme } from '@x402/evm/exact/client'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY)
const client = new x402Client().register('eip155:8453', new ExactEvmScheme(account))
const fetchWithPayment = wrapFetchWithPayment(fetch, client)

const body = {
  "url": "https://grist.tools/samples/documents/garden-plots.csv",
  "header": true
}

const res = await fetchWithPayment('https://grist.tools/v1/csv-to-json', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify(body),
})
console.log(res.status, await res.json())
const settle = res.headers.get('payment-response')
if (settle) console.log(decodePaymentResponseHeader(settle).transaction)

Python

# csv-to-json: $0.005 per call, paid in USD Coin on eip155:8453 via x402
# Install: pip install "x402[requests,evm]>=2.24,<3"
# The session reads the 402 (payment-required), signs and retries with payment-signature.
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http import decode_payment_response_header
from x402.http.clients.requests import x402_requests
from x402.mechanisms.evm.exact import register_exact_evm_client
from x402.mechanisms.evm.signers import EthAccountSigner

account = Account.from_key(os.environ["EVM_PRIVATE_KEY"])
client = x402ClientSync()
register_exact_evm_client(client, EthAccountSigner(account), networks="eip155:8453")
session = x402_requests(client)

payload = {
    "url": "https://grist.tools/samples/documents/garden-plots.csv",
    "header": True
}

res = session.post("https://grist.tools/v1/csv-to-json", json=payload)
print(res.status_code, res.json())
settle = res.headers.get("payment-response")
if settle:
    print(decode_payment_response_header(settle).transaction)

curl

# csv-to-json: $0.005 per call, paid in USD Coin on eip155:8453 via x402
# 1. Unpaid call: HTTP 402, the requirements in the payment-required header (base64 JSON) and in the body.
curl -i -X POST 'https://grist.tools/v1/csv-to-json' -H 'content-type: application/json' -d '{"url":"https://grist.tools/samples/documents/garden-plots.csv","header":true}'

# 2. Same call with the signed payment (an EIP-3009 authorization, EIP-712 signed: it cannot be
#    typed by hand). x-payment is accepted as the v1 alternative. HTTP 200 carries payment-response.
curl -i -X POST 'https://grist.tools/v1/csv-to-json' -H 'content-type: application/json' -H 'payment-signature: <base64 x402 payload>' -d '{"url":"https://grist.tools/samples/documents/garden-plots.csv","header":true}'

06Errors

Code	HTTP	For this service
invalid_input	400	The body does not match the schema; its fields are url, delimiter, header and max_rows.
blocked_target	403
unreachable_target	424
upstream_timeout	424
unsupported_content_type	415	The source is not a type csv-to-json reads; it reads CSV and TSV.
too_large	413
unprocessable	422
internal	500

Input that is rejected before the tool runs (malformed JSON, schema mismatch, body over the size limit) is never charged.

When each code is raised, and what it means for payment: /docs/csv-to-json.

07Conversions

Conversion	Recorded sample	Source size	Output size
CSV to JSON	documents/garden-plots.csv	220 bytes	396 bytes
TSV to JSON	documents/garden-plots.tsv	212 bytes	396 bytes

08Questions

How much does a csv-to-json call cost?: $0.005 per call, paid in USDC on Base via x402, with no account and no API key.
What does csv-to-json return?: A JSON object with 6 top-level fields: source_url, delimiter, columns, rows, row_count and truncated. The example on this page is a real call over documents/garden-plots.csv.
What happens when a csv-to-json call fails?: The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled. A 503 upstream_unavailable can follow a settled call; the x402 payments guide covers it, 429, 402 and an uncertain 500.

09Related

Documents guide