HTML to PDF API
Renders a web page or an inline HTML string to a PDF, returned base64-encoded with its page count.
- Endpoint
POST /v1/html-to-pdf- Price
- $0.005 per call
- Family
- Documents
01When to use it
- It needs a headless browser AND a hardened fetch: an agent that renders a URL itself walks the browser straight past every SSRF control, and carrying a Chromium is not something an agent does per call.
- Your source is HTML and you need PDF.
When not to use it
- The input is over 5 MB (5,242,880 bytes): html-to-pdf answers too_large (413).
- The destination needs more than 12 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 | no | Absolute http(s) URL of an HTML or XHTML page to fetch and render, up to 2048 characters; redirects are followed, the body is capped at 5 MB, and exactly one of url or html is required. |
| html | string | no | Self-contained HTML. Inline PNG data images are supported; external images, stylesheets and fonts are blocked. JavaScript is disabled. |
| format | string | no | Paper size of every page, A4 by default. One of: "A3", "A4", "A5", "Letter", "Legal", "Tabloid". Default: "A4". |
| landscape | boolean | no | Print in landscape orientation instead of portrait. Default: false. |
03Limits
| Limit | Value |
|---|---|
| Largest source file | 5 MB (5,242,880 bytes) |
| Timeout | 12 s |
| Source formats | HTML |
| Output formats |
04Example
The published example of html-to-pdf, verbatim: the request body and the response it returns.
Request
POST /v1/html-to-pdf
content-type: application/json
payment-signature: <base64 x402 payload>
{
"url": "https://grist.tools/samples/web/render-print.html",
"format": "A4",
"landscape": false
}Response
200 OK
payment-response: <base64 settlement receipt>
{
"source_url": "https://grist.tools/samples/web/render-print.html",
"pages": 1,
"bytes": 38404,
"format": "A4",
"landscape": false,
"pdf_base64": "JVBERi0xLjcKJYGBgYEKCjYgMCBvYmoKPDwKL0ZpbHRlciAvRmxhdGVEZWNvZGUK...",
"rendered_at": "2026-09-01T12:00:00.000Z"
}Sample file: web/render-print.html. Printable one-page HTML table with inline CSS: a weekly rain gauge reading schedule.
In the sample itself, the document declares language en and the title "Rain Gauge Reading Schedule"; 1 style element carries 8 CSS rules; the body holds 28 td, 8 tr, 4 th, 1 a, 1 footer, 1 h1, 1 p, 1 table, 1 tbody and 1 thead elements; no script element; its heading reads "Rain Gauge Reading Schedule"; the table header cells are Day, Reader, Reading (mm) and Notes; its one link points to render-article.html. Across the whole file, the markup opens 53 tags, 3 of them inside the head. In the returned PDF: the file opens with the header line %PDF-1.7, then a comment of four bytes above 0x7F that marks the file as binary. The first object in the file is number 6, generation 0, a stream compressed with FlateDecode.
| Response field | Type | In the example |
|---|---|---|
| source_url | string | "https://grist.tools/samples/web/render-print.html" |
| pages | number | 1 |
| bytes | number | 38404 |
| format | string | "A4" |
| landscape | boolean | false |
| pdf_base64 | string | a string of 67 characters |
| rendered_at | string | "2026-09-01T12:00:00.000Z" |
05Call it from code
JavaScript
// html-to-pdf: $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/web/render-print.html",
"format": "A4",
"landscape": false
}
const res = await fetchWithPayment('https://grist.tools/v1/html-to-pdf', {
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
# html-to-pdf: $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/web/render-print.html",
"format": "A4",
"landscape": False
}
res = session.post("https://grist.tools/v1/html-to-pdf", json=payload)
print(res.status_code, res.json())
settle = res.headers.get("payment-response")
if settle:
print(decode_payment_response_header(settle).transaction)curl
# html-to-pdf: $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/html-to-pdf' -H 'content-type: application/json' -d '{"url":"https://grist.tools/samples/web/render-print.html","format":"A4","landscape":false}'
# 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/html-to-pdf' -H 'content-type: application/json' -H 'payment-signature: <base64 x402 payload>' -d '{"url":"https://grist.tools/samples/web/render-print.html","format":"A4","landscape":false}'06Errors
| Code | HTTP | For this service |
|---|---|---|
| invalid_input | 400 | The body does not match the schema; its fields are url, html, format and landscape. |
| blocked_target | 403 | |
| unreachable_target | 424 | |
| upstream_timeout | 424 | |
| 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/html-to-pdf.
07Conversions
| Conversion | Recorded sample | Source size | Output size |
|---|---|---|---|
| HTML to PDF | web/render-print.html | 1.4 KB | 37.5 KB |
08Questions
- How much does a html-to-pdf call cost?
- $0.005 per call, paid in USDC on Base via x402, with no account and no API key.
- What does html-to-pdf return?
- A JSON object with 7 top-level fields: source_url, pages, bytes, format, landscape, pdf_base64 and rendered_at. The example on this page is a real call over web/render-print.html.
- What happens when a html-to-pdf 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.