OCR Text Recognition

Inference Space provides OCR text recognition: upload an image or PDF and receive structured recognized text and layout blocks (blocks). The endpoint accepts multipart/form-data uploads and can route requests to multiple OCR providers.

The private deployment API is identical; only replace the Base domain → Enterprise private deployment.

Overview

• Endpoint: POST https://ai.inf.space/v1/recognize, multipart/form-data.
• OCR providers: paddleocr, volcengine, and aliyun. The enabled and default providers are shown in the console.

Authentication and Base

• Host: OCR is a master/control-plane endpoint at https://ai.inf.space; send curl and SDK requests to the documented /v1/recognize path.
• Authentication header: Authorization: Bearer $TOS_API_KEY. Keys start with gk_.
• scope: ai:ocr is required. Select it when creating the key; the ai:* wildcard also works.

See Authentication.

Fields

• Supported formats: png / jpg (jpeg is normalized to jpg) / webp / bmp / pdf.
• Maximum image size: 50 MB. Larger files return 400.

Request examples

  curl "https://ai.inf.space/v1/recognize" \
  -H "Authorization: Bearer $TOS_API_KEY" \
  -F "image=@invoice.png" \
  -F "scene=document" \
  -F "language=zh-CN"

import os
import requests

with open("invoice.png", "rb") as f:
    resp = requests.post(
        "https://ai.inf.space/v1/recognize",
        headers={"Authorization": f"Bearer {os.environ['TOS_API_KEY']}"},
        data={"scene": "document", "language": "zh-CN"},
        files={"image": ("invoice.png", f, "image/png")},
        timeout=120,
    )
resp.raise_for_status()
data = resp.json()
print(data["text"])

import fs from "node:fs";

const form = new FormData();
form.set("scene", "document");
form.set("language", "zh-CN");
form.append("image", new Blob([fs.readFileSync("invoice.png")]), "invoice.png");

const resp = await fetch("https://ai.inf.space/v1/recognize", {
  method: "POST",
  headers: { "Authorization": `Bearer ${process.env.TOS_API_KEY}` },
  body: form,
});
const data = await resp.json();
console.log(data.text);

Response

The response is JSON: text contains the concatenated full-page text, and blocks contains layout blocks with coordinates. Multi-page documents such as PDFs include page_count and per-page results in pages.

{
  "text": "Invoice code: 031001900111\nTotal: CNY 1,280.00",
  "blocks": [
    { "text": "Invoice code: 031001900111", "box": [10, 12, 220, 40], "score": 0.99 }
  ],
  "page_count": 1,
  "pages": [
    { "text": "...", "blocks": [] }
  ]
}

Error handling

• 400: Invalid parameters, an empty file, an unsupported format, a file larger than 50 MB, or an unreadable image (invalid_image).
• 429: Rate limit exceeded; the response may include retry-after.
• 502 / 504: Upstream OCR provider error or timeout.

Related pages

• Authentication
• Image generation and editing
• Speech recognition (ASR) and speech synthesis (TTS)
• Vision segmentation (SAM3 image/video)