Document OCR - H Platform Docs

Transcribe a page

No dedicated endpoint: the same OpenAI-compatible chat/completions call, with a page image and a transcription prompt, sent at temperature=0.0 with enable_thinking=False. The Markdown comes back in message.content. Client setup is in the Quickstart.

IMAGE_URL = "https://your-host/page.png"  # or "data:image/png;base64,..."

OCR_PROMPT = (
    "Transcribe this document page to Markdown, preserving the reading order, "
    "headings, lists, and tables. Render tables as Markdown tables and equations "
    "as LaTeX. Return only the transcription, with no commentary and no surrounding "
    "code fence. If the page has no readable text, return an empty string."
)

response = client.chat.completions.create(
    model="holo3-1-35b-a3b",
    messages=[{
        "role": "user",
        "content": [
            {"type": "image_url", "image_url": {"url": IMAGE_URL}},
            {"type": "text", "text": OCR_PROMPT},
        ],
    }],
    temperature=0.0,
    extra_body={"chat_template_kwargs": {"enable_thinking": False}},
)

print(response.choices[0].message.content)

const IMAGE_URL = "https://your-host/page.png"; // or "data:image/png;base64,..."

const OCR_PROMPT =
  "Transcribe this document page to Markdown, preserving the reading order, " +
  "headings, lists, and tables. Render tables as Markdown tables and equations " +
  "as LaTeX. Return only the transcription, with no commentary and no surrounding " +
  "code fence. If the page has no readable text, return an empty string.";

const response = await client.chat.completions.create({
  model: "holo3-1-35b-a3b",
  messages: [
    {
      role: "user",
      content: [
        { type: "image_url", image_url: { url: IMAGE_URL } },
        { type: "text", text: OCR_PROMPT },
      ],
    },
  ],
  temperature: 0.0,
  // chat_template_kwargs is H-specific, passed through in the request body
  ...({ chat_template_kwargs: { enable_thinking: false } } as any),
});

console.log(response.choices[0].message.content);

Input	Quality
English, digitally generated: exported PDFs, slides, web pages, reports	Strongest
Scanned pages and photos	Best effort
Handwriting, non-Latin scripts	Not a good fit; use a dedicated OCR system when stakes are high

Multi-page PDFs

Holo reads images, not PDFs, so rasterize each page to an image and transcribe them one per request, then stitch the results. One page per request keeps each image at full resolution and is the most reliable pattern.

import base64
import pymupdf  # pip install pymupdf

def ocr_page(png_bytes: bytes) -> str:
    data_uri = "data:image/png;base64," + base64.b64encode(png_bytes).decode()
    response = client.chat.completions.create(
        model="holo3-1-35b-a3b",
        messages=[{
            "role": "user",
            "content": [
                {"type": "image_url", "image_url": {"url": data_uri}},
                {"type": "text", "text": OCR_PROMPT},
            ],
        }],
        temperature=0.0,
        extra_body={"chat_template_kwargs": {"enable_thinking": False}},
    )
    return response.choices[0].message.content or ""

with pymupdf.open("document.pdf") as doc:
    pages = [ocr_page(page.get_pixmap(dpi=200).tobytes("png")) for page in doc]

markdown = "\n\n".join(pages)
print(markdown)

import { pdf } from "pdf-to-img"; // npm install pdf-to-img

async function ocrPage(png: Buffer): Promise<string> {
  const dataUri = "data:image/png;base64," + png.toString("base64");
  const response = await client.chat.completions.create({
    model: "holo3-1-35b-a3b",
    messages: [
      {
        role: "user",
        content: [
          { type: "image_url", image_url: { url: dataUri } },
          { type: "text", text: OCR_PROMPT },
        ],
      },
    ],
    temperature: 0.0,
    ...({ chat_template_kwargs: { enable_thinking: false } } as any),
  });
  return response.choices[0].message.content ?? "";
}

const pages: string[] = [];
for await (const page of await pdf("document.pdf", { scale: 2 })) {
  pages.push(await ocrPage(page));
}

const markdown = pages.join("\n\n");
console.log(markdown);

Next steps

Element localization

Get click coordinates from a screenshot.

Build an agent

How to use Holo in your computer-use harness.

API reference

Endpoint, auth, rate limits, and errors.