How much does a ocr-image-to-text call cost?

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

What does ocr-image-to-text return?

A JSON object with 5 top-level fields: source_url, lang, image_format, text and confidence. The example on this page is a real call over images/ocr-scan.png.

What happens when a ocr-image-to-text 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 / OCR Image to Text API

OCR Image to Text API

Reads the text out of an image (scan, screenshot, photo) with Tesseract, returned with a mean confidence.

Endpoint: POST /v1/ocr-image-to-text
Price: $0.005 per call
Family: Documents
Docs: /docs/ocr-image-to-text

01When to use it

OCR needs a real engine and its language data AND a hardened fetch: an agent that pulls the image URL itself walks past every SSRF control, and carrying a WASM Tesseract plus a language model is not something an agent does per call.
Your source is GIF, JPEG, PNG, TIFF or WebP and you need plain text.

When not to use it

The input is over 10 MB (10,485,760 bytes): ocr-image-to-text answers too_large (413).
The destination needs more than 45 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	Absolute http(s) URL of the image, up to 2048 characters and 10 MB; redirects are followed, the bytes must be PNG, JPEG, TIFF, WebP or GIF by signature, and at most 40 megapixels.
lang	string	no	Tesseract language model to read the text with; only languages whose data ships with the service are accepted, today eng (the default). One of: "eng". Default: "eng".

03Limits

Limit	Value
Largest source file	10 MB (10,485,760 bytes)
Timeout	45 s
Source formats	GIF, JPEG, PNG, TIFF, WebP
Output formats	plain text

04Example

The published example of ocr-image-to-text, verbatim: the request body and the response it returns.

Request

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

{
  "url": "https://grist.tools/samples/images/ocr-scan.png",
  "lang": "eng"
}

Response

200 OK
payment-response: <base64 settlement receipt>

{
  "source_url": "https://grist.tools/samples/images/ocr-scan.png",
  "lang": "eng",
  "image_format": "png",
  "text": "SAMPLE SCAN FOR OCR\nSECOND LINE 2026\n",
  "confidence": 86
}

Sample file: images/ocr-scan.png. 1-bit black-on-white PNG with two uppercase lines drawn from a hand-written 5x7 bitmap font: SAMPLE SCAN FOR OCR and SECOND LINE 2026.

In the sample itself: its IHDR chunk declares 556 by 100 pixels, 1-bit greyscale and no interlacing. The chunks run IHDR, IDAT and IEND. The returned text runs to 3 lines, 1 blank one among them, and its longest line, "SAMPLE SCAN FOR OCR", holds 19 characters. Its first line reads "SAMPLE SCAN FOR OCR" and its last "SECOND LINE 2026". Split on whitespace, it yields 7 tokens over 2 non-blank lines.

Response field	Type	In the example
source_url	string	"https://grist.tools/samples/images/ocr-scan.png"
lang	string	"eng"
image_format	string	"png"
text	string	"SAMPLE SCAN FOR OCR SECOND LINE 2026 "
confidence	number	86

05Call it from code

JavaScript

// ocr-image-to-text: $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/images/ocr-scan.png",
  "lang": "eng"
}

const res = await fetchWithPayment('https://grist.tools/v1/ocr-image-to-text', {
  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

# ocr-image-to-text: $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/images/ocr-scan.png",
    "lang": "eng"
}

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

curl

# ocr-image-to-text: $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/ocr-image-to-text' -H 'content-type: application/json' -d '{"url":"https://grist.tools/samples/images/ocr-scan.png","lang":"eng"}'

# 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/ocr-image-to-text' -H 'content-type: application/json' -H 'payment-signature: <base64 x402 payload>' -d '{"url":"https://grist.tools/samples/images/ocr-scan.png","lang":"eng"}'

06Errors

Code	HTTP	For this service
invalid_input	400	The body does not match the schema; its fields are url and lang.
blocked_target	403
unreachable_target	424
upstream_timeout	424
unsupported_content_type	415	The source is not a type ocr-image-to-text reads; it reads GIF, JPEG, PNG, TIFF and WebP.
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/ocr-image-to-text.

07Conversions

Conversion	Recorded sample	Source size	Output size
GIF to plain text	images/pair-note.gif	1.9 KB	37 bytes
JPEG to plain text	images/pair-note.jpg	5.2 KB	37 bytes
PNG to plain text	images/ocr-scan.png	7 KB	37 bytes
TIFF to plain text	images/pair-note.tiff	3.6 KB	37 bytes
WebP to plain text	images/pair-note.webp	248 bytes	37 bytes

08Questions

How much does a ocr-image-to-text call cost?: $0.005 per call, paid in USDC on Base via x402, with no account and no API key.
What does ocr-image-to-text return?: A JSON object with 5 top-level fields: source_url, lang, image_format, text and confidence. The example on this page is a real call over images/ocr-scan.png.
What happens when a ocr-image-to-text 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