HTML to PDF in Java

Send HTML (or a URL) to the FrameForge API and get a PDF back. It is rendered in real Chromium, so modern CSS, web fonts and JavaScript all work. No browser to install or babysit.

The code

Java 11+ (java.net.http). Set FRAMEFORGE_KEY to your API key.

import java.net.URI;
import java.net.http.*;
import java.nio.file.Path;
import java.time.Duration;

public class RenderPdf {
  public static void main(String[] args) throws Exception {
    String json = "{\"html\":\"<h1>Invoice #1001</h1>\",\"format\":\"pdf\",\"width\":794,\"height\":1123}";
    HttpRequest req = HttpRequest.newBuilder(URI.create("https://api.frameforgeapi.com/render"))
        .header("Content-Type", "application/json")
        .header("X-API-Key", System.getenv("FRAMEFORGE_KEY"))
        .timeout(Duration.ofSeconds(60))
        .POST(HttpRequest.BodyPublishers.ofString(json))
        .build();
    HttpResponse<Path> res = HttpClient.newHttpClient()
        .send(req, HttpResponse.BodyHandlers.ofFile(Path.of("invoice.pdf")));
    if (res.statusCode() != 200) throw new RuntimeException("Render failed: " + res.statusCode());
  }
}

How it works

• POST /render takes JSON with exactly one of html (up to 1 MiB) or url, plus format (png, jpeg or pdf), width and height (1 to 3840 px) and fullPage.
• The response body is the file itself (application/pdf), not JSON, so write the bytes straight to disk or stream them to the user.
• Page size: the PDF page is width × height pixels. 794 × 1123 is A4 at 96 DPI and 816 × 1056 is US Letter. Content longer than one page flows onto more pages of the same size. With fullPage: true you get one tall page instead.
• Margins: pages have no printer margins, so add padding in your HTML (for example body { padding: 48px }).
• Caching: identical requests within 24 hours are served from cache and don't count against your quota. Check the X-FrameForge-Cache response header.
• Errors come back as JSON with an error code: 401 bad key, 429 rate limited, 400 blocked_url for private or local addresses.

Rendering a URL instead of HTML

{"url": "https://example.com/report", "format": "pdf", "width": 1280, "height": 800, "fullPage": true}

Doing it yourself instead

Playwright for Java runs Chromium locally, and OpenHTMLtoPDF renders XHTML with CSS 2.1-level support.

An API makes sense when you don't want Chromium on your servers, or when you need images (PNG/JPEG) and PDFs from the same call. If you render a few PDFs a month on a server you already run, self-hosting is perfectly reasonable.

Free tool: Website to PDF. Other languages: Node.js · Python · PHP · Ruby · Go · C# / .NET · curl / Bash · Next.js · Laravel · Django · Ruby on Rails