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Gemini Document Understanding

POST /v1beta/models/{model}:generateContent
As of March 23, 2026, Crazyrouter production has verified that gemini-3-pro-preview supports:
  • Reading PDFs through inlineData
  • Returning parseable JSON when responseMimeType and responseSchema are provided

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PDF Summary

The following request successfully read a PDF and returned a summary in production: 
curl "https://crazyrouter.com/v1beta/models/gemini-3-pro-preview:generateContent?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [
          {"text": "Summarize the attached PDF in one sentence."},
          {
            "inlineData": {
              "mimeType": "application/pdf",
              "data": "JVBERi0xLjQK..."
            }
          }
        ]
      }
    ]
  }'
In the production check, the model returned a one-sentence summary of the attached PDF.

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PDF + Structured Output

The following request returned JSON text that could be parsed directly with json.loads() in production: 
curl "https://crazyrouter.com/v1beta/models/gemini-3-pro-preview:generateContent?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {
        "role": "user",
        "parts": [
          {"text": "Extract the key topic and whether the document mentions gamma."},
          {
            "inlineData": {
              "mimeType": "application/pdf",
              "data": "JVBERi0xLjQK..."
            }
          }
        ]
      }
    ],
    "generationConfig": {
      "responseMimeType": "application/json",
      "responseSchema": {
        "type": "object",
        "properties": {
          "topic": {"type": "string"},
          "mentions_gamma": {"type": "boolean"}
        },
        "required": ["topic", "mentions_gamma"]
      }
    }
  }'
Observed production response: 
{
  "candidates": [
    {
      "content": {
        "parts": [
          {
            "text": "{\n  \"topic\": \"Crazyrouter PDF test document\",\n  \"mentions_gamma\": false\n}"
          }
        ]
      }
    }
  ]
}
You can parse it directly: 
import json

text = response["candidates"][0]["content"]["parts"][0]["text"]
data = json.loads(text)
This page only confirms the PDF-input path and JSON structured output path. For table extraction, long-document comparison, or other higher-variance workflows, revalidate with your own sample documents first.
Large PDFs materially increase input-token usage. Validate prompts and schemas with small documents first, then scale up.