File input methods

This guide explains the different ways you can include media files such as images, audio, video, and documents when making requests to the Gemini API. Choosing the right method depends on the size of your file, where your data is currently stored, and how frequently you plan to use the file.

The simplest way to include a file as your input is to read a local file and include it in a prompt. The following example shows how to read a local PDF file. PDFs are limited to 50MB for this method. See the Input method comparison table for a complete list of file input types and limits.

from google import genai
from google.genai import types
import pathlib

client = genai.Client()

filepath = pathlib.Path('my_local_file.pdf')

prompt = "Summarize this document"
response = client.models.generate_content(
  model="gemini-3-flash-preview",
  contents=[
      types.Part.from_bytes(
        data=filepath.read_bytes(),
        mime_type='application/pdf',
      ),
      prompt
  ]
)
print(response.text)

import { GoogleGenAI } from "@google/genai";
import * as fs from 'node:fs';

const ai = new GoogleGenAI({});
const prompt = "Summarize this document";

async function main() {
    const filePath = path.join('content', 'my_local_file.pdf'); // Adjust path as needed

    const contents = [
        { text: prompt },
        {
            inlineData: {
                mimeType: 'application/pdf',
                data: fs.readFileSync(filePath).toString("base64")
            }
        }
    ];

    const response = await ai.models.generateContent({
        model: "gemini-3-flash-preview",
        contents: contents
    });
    console.log(response.text);
}

main();

# Encode the local file to base64
B64_CONTENT=$(base64 -w 0 my_local_file.pdf)

curl -X POST "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-flash-preview:generateContent" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "contents": [
      {
        "parts": [
          {"text": "Summarize this document"}
        ]
      },
      {
        "parts": [
          {
            "inlineData": {
              "mimeType": "application/pdf",
              "data": "'"${B64_CONTENT}"'"
            }
          }
        ]
      }
    ]
  }'

Input method comparison

The following table compares each input method with file limits and best use cases. Note that the file size limit may vary depending on the file type and model/tokenizer used to process the file.

Inline data

For smaller files (under 100MB, or 50MB for PDFs), you can pass the data directly in the request payload. This is the simplest method for quick tests or applications handling real-time, transient data. You can provide data as base64 encoded strings or by reading local files directly.

For an example of reading from a local file, see the example at the beginning of this page.

Fetch from a URL

You can also fetch a file from a URL, convert it to bytes, and include it in the input.

from google import genai
from google.genai import types
import httpx

client = genai.Client()

doc_url = "https://discovery.ucl.ac.uk/id/eprint/10089234/1/343019_3_art_0_py4t4l_convrt.pdf"
doc_data = httpx.get(doc_url).content

prompt = "Summarize this document"

response = client.models.generate_content(
  model="gemini-3-flash-preview",
  contents=[
      types.Part.from_bytes(
        data=doc_data,
        mime_type='application/pdf',
      ),
      prompt
  ]
)
print(response.text)

import { GoogleGenAI } from "@google/genai";

const ai = new GoogleGenAI({});
const docUrl = 'https://discovery.ucl.ac.uk/id/eprint/10089234/1/343019_3_art_0_py4t4l_convrt.pdf';
const prompt = "Summarize this document";

async function main() {
    const pdfResp = await fetch(docUrl);
      .then((response) => response.arrayBuffer());

    const contents = [
        { text: prompt },
        {
            inlineData: {
                mimeType: 'application/pdf',
                data: Buffer.from(pdfResp).toString("base64")
            }
        }
    ];

    const response = await ai.models.generateContent({
        model: "gemini-3-flash-preview",
        contents: contents
    });
    console.log(response.text);
}

main();

DOC_URL="https://discovery.ucl.ac.uk/id/eprint/10089234/1/343019_3_art_0_py4t4l_convrt.pdf"
PROMPT="Summarize this document"
DISPLAY_NAME="base64_pdf"

# Download the PDF
wget -O "${DISPLAY_NAME}.pdf" "${DOC_URL}"

# Check for FreeBSD base64 and set flags accordingly
if [[ "$(base64 --version 2>&1)" = *"FreeBSD"* ]]; then
  B64FLAGS="--input"
else
  B64FLAGS="-w0"
fi

# Base64 encode the PDF
ENCODED_PDF=$(base64 $B64FLAGS "${DISPLAY_NAME}.pdf")

# Generate content using the base64 encoded PDF
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-flash-preview:generateContent" \
    -H "x-goog-api-key: $GEMINI_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts":[
          {"inline_data": {"mime_type": "application/pdf", "data": "'"$ENCODED_PDF"'"}},
          {"text": "'$PROMPT'"}
        ]
      }]
    }' 2> /dev/null > response.json

cat response.json
echo

jq ".candidates[].content.parts[].text" response.json

Gemini File API

The File API is designed for larger files (up to 2GB) or files you intend to use in multiple requests.

Standard file upload

Upload a local file to the Gemini API. Files uploaded this way are stored temporarily (48 hours) and processed for efficient retrieval by the model.

from google import genai
client = genai.Client()

# Upload the file
audio_file = client.files.upload(file="path/to/your/sample.mp3")
prompt = "Describe this audio clip"

# Use the uploaded file in a prompt
response = client.models.generate_content(
    model="gemini-3-flash-preview",
    contents=[prompt, audio_file]
)
print(response.text)

import {
  GoogleGenAI,
  createUserContent,
  createPartFromUri,
} from "@google/genai";

const ai = new GoogleGenAI({});
const prompt = "Describe this audio clip";

async function main() {
  const filePath = "path/to/your/sample.mp3"; // Adjust path as needed

  const myfile = await ai.files.upload({
    file: filePath,
    config: { mimeType: "audio/mpeg" },
  });

  const response = await ai.models.generateContent({
    model: "gemini-3-flash-preview",
    contents: createUserContent([
      prompt,
      createPartFromUri(myfile.uri, myfile.mimeType),
    ]),
  });
  console.log(response.text);

}
await main();

AUDIO_PATH="path/to/sample.mp3"
MIME_TYPE=$(file -b --mime-type "${AUDIO_PATH}")
NUM_BYTES=$(wc -c < "${AUDIO_PATH}")
DISPLAY_NAME=AUDIO

tmp_header_file=upload-header.tmp

# Initial resumable request defining metadata.
# The upload url is in the response headers dump them to a file.
curl "${BASE_URL}/upload/v1beta/files" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -D "${tmp_header_file}" \
  -H "X-Goog-Upload-Protocol: resumable" \
  -H "X-Goog-Upload-Command: start" \
  -H "X-Goog-Upload-Header-Content-Length: ${NUM_BYTES}" \
  -H "X-Goog-Upload-Header-Content-Type: ${MIME_TYPE}" \
  -H "Content-Type: application/json" \
  -d "{'file': {'display_name': '${DISPLAY_NAME}'}}" 2> /dev/null

upload_url=$(grep -i "x-goog-upload-url: " "${tmp_header_file}" | cut -d" " -f2 | tr -d "\r")
rm "${tmp_header_file}"

# Upload the actual bytes.
curl "${upload_url}" \
  -H "Content-Length: ${NUM_BYTES}" \
  -H "X-Goog-Upload-Offset: 0" \
  -H "X-Goog-Upload-Command: upload, finalize" \
  --data-binary "@${AUDIO_PATH}" 2> /dev/null > file_info.json

file_uri=$(jq ".file.uri" file_info.json)
echo file_uri=$file_uri

# Now generate content using that file
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-3-flash-preview:generateContent" \
    -H "x-goog-api-key: $GEMINI_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts":[
          {"text": "Describe this audio clip"},
          {"file_data":{"mime_type": "${MIME_TYPE}", "file_uri": '$file_uri'}}]
        }]
      }' 2> /dev/null > response.json

cat response.json
echo

jq ".candidates[].content.parts[].text" response.json

Register Google Cloud Storage files

If your data is already in Google Cloud Storage, you don't need to download and re-upload it. You can register it directly with the File API.

1. Grant Service Agent access to each bucket

   1. Enable the Gemini API in your Google Cloud project.

   2. Create the Service Agent:

      gcloud beta services identity create --service=generativelanguage.googleapis.com --project=<your_project>

   3. Grant the Gemini API Service Agent permissions to read your storage buckets.

      The user needs to assign the Storage Object Viewer IAM role to this service agent on the specific storage buckets they intend to use.

   This access doesn't expire by default, but can be changed at any time. You can also use the Google Cloud Storage IAM SDK commands to grant permissions.

2. Authenticate your service

   Prerequisites

   • Enable API
   • Create a service account/agent with appropriate permissions.

   You first need to authenticate as the service that has storage object viewer permissions. How this happens depends on the environment in which your file management code will be running.

   Outside of Google Cloud

   If your code is running from outside of Google Cloud, such as your desktop, download the account credentials from the Google Cloud Console with the following steps:

   1. Browse to the Service Account console
   2. Select the relevant service account
   3. Select the Keys tab and choose Add key, Create new key
   4. Choose the JSON key type, and note where the file was downloaded to on your machine.

   For more details, see the official Google Cloud documentation on service account key management.

   Then use the following commands to authenticate. These commands assume your service account file is in the current directory, named service-account.json.

   Python

   from google.oauth2.service_account import Credentials
   
   GCS_READ_SCOPES = [       
     'https://www.googleapis.com/auth/devstorage.read_only',
     'https://www.googleapis.com/auth/cloud-platform'
   ]
   
   SERVICE_ACCOUNT_FILE = 'service-account.json'
   
   credentials = Credentials.from_service_account_file(
       SERVICE_ACCOUNT_FILE,
       scopes=GCS_READ_SCOPES
   )
   

   Javascript

   const { GoogleAuth } = require('google-auth-library');
   
   const GCS_READ_SCOPES = [
     'https://www.googleapis.com/auth/devstorage.read_only',
     'https://www.googleapis.com/auth/cloud-platform'
   ];
   
   const SERVICE_ACCOUNT_FILE = 'service-account.json';
   
   const auth = new GoogleAuth({
     keyFile: SERVICE_ACCOUNT_FILE,
     scopes: GCS_READ_SCOPES
   });
   

   CLI

   gcloud auth application-default login \
     --client-id-file=service-account.json \
     --scopes='https://www.googleapis.com/auth/cloud-platform,https://www.googleapis.com/auth/devstorage.read_only'
   

   On Google Cloud

   If you are running directly in Google Cloud, for example by using Cloud Run functions or a Compute Engine instance, you will have implicit credentials but will need to re-authenticate to grant the appropriate scopes.

   Python

   This code expects that the service is running in an environment where Application Default Credentials can be obtained automatically, such as Cloud Run or Compute Engine.

   import google.auth
   
   GCS_READ_SCOPES = [       
     'https://www.googleapis.com/auth/devstorage.read_only',
     'https://www.googleapis.com/auth/cloud-platform'
   ]
   
   credentials, project = google.auth.default(scopes=GCS_READ_SCOPES)
   

   JavaScript

   This code expects that the service is running in an environment where Application Default Credentials can be obtained automatically, such as Cloud Run or Compute Engine.

   const { GoogleAuth } = require('google-auth-library');
   
   const auth = new GoogleAuth({
     scopes: [
       'https://www.googleapis.com/auth/devstorage.read_only',
       'https://www.googleapis.com/auth/cloud-platform'
     ]
   });
   

   CLI

   This is an interactive command. For services like Compute Engine you can attach scopes to the running service at the config level. See the user-managed service docs for an example.

   gcloud auth application-default login \
   --scopes="https://www.googleapis.com/auth/cloud-platform,https://www.googleapis.com/auth/devstorage.read_only"
   

3. File registration (Files API)

   Use the Files API to register files and produce a Files API path that can directly be used in the Gemini API.

   Python

   from google import genai
   from google.genai.types import Part
   
   # Note that you must provide an API key in the GEMINI_API_KEY
   # environment variable, but it is unused for the registration endpoint.
   client = genai.Client()
   
   registered_gcs_files = client.files.register_files(
       uris=["gs://my_bucket/some_object.pdf", "gs://bucket2/object2.txt"],
       # Use the credentials obtained in the previous step.
       auth=credentials
   )
   prompt = "Summarize this file."
   
   # call generateContent for each file
   for f in registered_gcs_files.files:
     print(f.name)
     response = client.models.generate_content(
       model="gemini-3-flash-preview",
       contents=[Part.from_uri(
         file_uri=f.uri,
         mime_type=f.mime_type,
       ),
       prompt],
     )
     print(response.text)
   

   CLI

   access_token=$(gcloud auth application-default print-access-token)
   project_id=$(gcloud config get-value project)
   curl -X POST https://generativelanguage.googleapis.com/v1beta/files:register \
       -H 'Content-Type: application/json' \
       -H "Authorization: Bearer ${access_token}" \
       -H "x-goog-user-project: ${project_id}" \
       -d '{"uris": ["gs://bucket/object1", "gs://bucket/object2"]}'
   

External HTTP / Signed URLs

You can pass publicly accessible HTTPS URLs or pre-signed URLs (compatible with S3 Presigned URLs and Azure SAS) directly in your generation request. The Gemini API will fetch the content securely during processing. This is ideal for files up to 100MB that you don't want to re-upload.

You can use public or signed URLs as input by using the URLs in the file_uri field.

from google import genai
from google.genai.types import Part

uri = "https://ontheline.trincoll.edu/images/bookdown/sample-local-pdf.pdf"
prompt = "Summarize this file"

client = genai.Client()

response = client.models.generate_content(
    model="gemini-3-flash-preview",
    contents=[
        Part.from_uri(
            file_uri=uri,
            mime_type="application/pdf",
        ),
        prompt
    ],
)
print(response.text)

import { GoogleGenAI, createPartFromUri } from '@google/genai';

const client = new GoogleGenAI({});

const uri = "https://ontheline.trincoll.edu/images/bookdown/sample-local-pdf.pdf";

async function main() {
  const response = await client.models.generateContent({
    model: 'gemini-3-flash-preview',
    contents: [
      // equivalent to Part.from_uri(file_uri=uri, mime_type="...")
      createPartFromUri(uri, "application/pdf"),
      "summarize this file",
    ],
  });

  console.log(response.text);
}

main();

curl "https://autopush-generativelanguage.sandbox.googleapis.com/v1beta/models/gemini-3-flash-preview:generateContent \
      -H 'x-goog-api-key: $GEMINI_API_KEY' \
      -H 'Content-Type: application/json' \
      -d '{
          "contents":[
            {
              "parts":[
                {"text": "Summarize this pdf"},
                {
                  "file_data": {
                    "mime_type":"application/pdf",
                    "file_uri": "https://ontheline.trincoll.edu/images/bookdown/sample-local-pdf.pdf"
                  }
                }
              ]
            }
          ]
        }'

Accessibility

Verify that the URLs you provide don't lead to pages that require a login or are behind a paywall. For private databases, ensure you create a signed URL with the correct access permissions and expiry.

Safety checks

The system performs a content moderation check on the URL to confirm they meet safety and policy standards (e.g. non-opted out & paywalled content). If the URL you provided fails this check, you will get an url_retrieval_status of URL_RETRIEVAL_STATUS_UNSAFE.

Supported content types

This list of supported file types and limitations is intended as initial guidance and is not comprehensive. The effective set of supported types is subject to change and can vary based on the specific model and tokenizer version in use. Unsupported types will result in an error. Additionally, content retrieval for these file types currently only supports publicly accessible URLs.

Best practices

• Choose the right method: Use inline data for small, transient files. Use the File API for larger or frequently used files. Use external URLs for data already hosted online.
• Specify MIME Types: Always provide the correct MIME type for the file data to ensure proper processing.
• Handle Errors: Implement error handling in your code to manage potential issues like network failures, file access problems, or API errors.
• Manage GCS Permissions: When using GCS registration, grant the Gemini API Service Agent only the necessary Storage Object Viewer role on the specific buckets.
• Signed URL Security: Ensure signed URLs have an appropriate expiration time and limited permissions.

Limitations

• File size limits vary by method (see comparison table) and file type.
• Inline data increases request payload size.
• File API uploads are temporary and expire after 48 hours.
• External URL fetching is limited to 100MB per payload and supports specific content types.
• Google Cloud Storage registration requires proper IAM setup and OAuth token management.

What's next

• Try writing your own multimodal prompts using Google AI Studio.
• For information on including files in your prompts, see the Vision, Audio, and Document processing guides.
• For more guidance on prompt design, like tuning sampling parameters, see the Prompt strategies guide.