HTML to PDF API#

The HTML to PDF API converts an uploaded HTML file into a high-quality PDF using WeasyPrint rendering. Send a .html or .htm file to POST /v1/convert/html-to-pdf and the rendered PDF is returned synchronously: raw bytes by default, or JSON metadata with a presigned download URL when direct_download=false. Page size, margins, orientation, headers, footers, and grayscale output are all controlled via pdf_options.

Endpoint#

POST /v1/convert/html-to-pdf

Content-Type: multipart/form-data

Accepted input: .html or .htm files (UTF-8 encoded)

Output format: .pdf (application/pdf)

Authentication#

Requires either a private API key or a JWT token from a public key.

X-API-Key: sk_your_private_key

Or:

Authorization: Bearer <jwt_token>

Request Parameters#

PDF Options#

Pass as a JSON string in the pdf_options form field. All fields are optional.

Supported page sizes: A0, A1, A2, A3, A4, A5, A6, B0, B1, B2, B3, B4, B5, Letter, Legal, Tabloid, Ledger

Header/footer template variables: {{page}}, {{total_pages}}, {{date}}, {{title}}, {{url}}

Conversion Details#

• Uses WeasyPrint for CSS-based PDF rendering
• The pdf_options are translated into CSS @page rules injected into the HTML before rendering
• WeasyPrint respects the document's own CSS styles in addition to the injected page rules
• All rendering is synchronous and server-side

Response#

Direct Download (direct_download=true, default)#

HTTP 200 OK
Content-Type: application/pdf
Content-Disposition: inline; filename="document_20260405_123456789.pdf"

Returns raw PDF bytes.

Metadata Response (direct_download=false)#

{
    "presigned_url": "https://spaces.example.com/...",
    "object_key": "env/files/{project_id}/html-to-pdf/document_20260405_123456789.pdf",
    "filename": "document_20260405_123456789.pdf",
    "file_size": 45678,
    "conversion_time_seconds": 1.2
}

Code Examples#

Python#

import requests
import json

with open("report.html", "rb") as f:
    response = requests.post(
        "https://api.enconvert.com/v1/convert/html-to-pdf",
        headers={"X-API-Key": "sk_your_private_key"},
        files={"file": ("report.html", f, "text/html")},
        data={
            "pdf_options": json.dumps({
                "page_size": "A4",
                "orientation": "portrait",
                "margins": {"top": 20, "bottom": 20, "left": 15, "right": 15}
            })
        }
    )

with open("report.pdf", "wb") as out:
    out.write(response.content)

Node.js#

const form = new FormData();
form.append("file", fs.createReadStream("report.html"));
form.append("pdf_options", JSON.stringify({
    page_size: "A4",
    orientation: "portrait",
    margins: { top: 20, bottom: 20, left: 15, right: 15 }
}));

const response = await fetch("https://api.enconvert.com/v1/convert/html-to-pdf", {
    method: "POST",
    headers: { "X-API-Key": "sk_your_private_key" },
    body: form
});

fs.writeFileSync("report.pdf", Buffer.from(await response.arrayBuffer()));

PHP#

$ch = curl_init("https://api.enconvert.com/v1/convert/html-to-pdf");
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ["X-API-Key: sk_your_private_key"],
    CURLOPT_POSTFIELDS => [
        "file" => new CURLFile("report.html", "text/html"),
        "pdf_options" => json_encode([
            "page_size" => "A4",
            "margins" => ["top" => 20, "bottom" => 20, "left" => 15, "right" => 15]
        ])
    ]
]);
$pdf = curl_exec($ch);
curl_close($ch);
file_put_contents("report.pdf", $pdf);

Go#

body := &bytes.Buffer{}
writer := multipart.NewWriter(body)

part, _ := writer.CreateFormFile("file", "report.html")
file, _ := os.Open("report.html")
io.Copy(part, file)

writer.WriteField("pdf_options", `{"page_size":"A4","margins":{"top":20,"bottom":20,"left":15,"right":15}}`)
writer.Close()

req, _ := http.NewRequest("POST", "https://api.enconvert.com/v1/convert/html-to-pdf", body)
req.Header.Set("Content-Type", writer.FormDataContentType())
req.Header.Set("X-API-Key", "sk_your_private_key")
resp, _ := http.DefaultClient.Do(req)

Error Responses#

Limits#

Frequently asked questions#

How do I convert HTML to PDF with a REST API?#

Send a multipart/form-data request to POST /v1/convert/html-to-pdf with your .html or .htm file in the file field, authenticated via X-API-Key or a Bearer JWT. By default the response is the raw PDF bytes with Content-Type: application/pdf.

Can I set a custom page size, margins, or orientation for the PDF?#

Yes. Pass a JSON string in the pdf_options form field with page_size (e.g. A4, Letter, Legal), margins in millimeters, and orientation (portrait or landscape). For non-standard dimensions, set page_width and page_height together in millimeters.

How do I add page numbers or headers and footers to the generated PDF?#

Set header or footer in pdf_options as {"content": "<text>", "height": 15}. The content supports the template variables {{page}}, {{total_pages}}, {{date}}, {{title}}, and {{url}}, and is limited to 2000 characters.

Why are images, fonts, or stylesheets missing from my PDF output?#

External resources referenced by URL in the HTML may not resolve during server-side rendering. Use inline CSS and base64-encoded images, or make sure all referenced resources are publicly accessible.

Can I get a download URL instead of raw PDF bytes?#

Yes. Set direct_download=false and the endpoint returns JSON metadata including a presigned_url, object_key, filename, file_size, and conversion_time_seconds instead of the PDF body.