Batch API

The Gemini Batch API is designed to process large volumes of requests asynchronously at 50% of the standard cost. The target turnaround time is 24 hours, but in majority of cases, it is much quicker.

Use Batch API for large-scale, non-urgent tasks such as data pre-processing or running evaluations where an immediate response is not required.

Creating a batch job

You have two ways to submit your requests in Batch API:

  • Inline requests: A list of GenerateContentRequest objects directly included in your batch creation request. This is suitable for smaller batches that keep the total request size under 20MB. The output returned from the model is a list of inlineResponse objects.
  • Input file: A JSON Lines (JSONL) file where each line contains a complete GenerateContentRequest object. This method is recommended for larger requests. The output returned from the model is a JSONL file where each line is either a GenerateContentResponse or a status object.

Inline requests

For a small number of requests, you can directly embed the GenerateContentRequest objects within your BatchGenerateContentRequest. The following example calls the BatchGenerateContent method with inline requests:

Python


from google import genai
from google.genai import types

client = genai.Client()

# A list of dictionaries, where each is a GenerateContentRequest
inline_requests = [
    {
        'contents': [{
            'parts': [{'text': 'Tell me a one-sentence joke.'}],
            'role': 'user'
        }]
    },
    {
        'contents': [{
            'parts': [{'text': 'Why is the sky blue?'}],
            'role': 'user'
        }]
    }
]

inline_batch_job = client.batches.create(
    model="gemini-3.7-flash",
    src=inline_requests,
    config={
        'display_name': "inlined-requests-job-1",
    },
)

print(f"Created batch job: {inline_batch_job.name}")

JavaScript


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

const ai = new GoogleGenAI({});

const inlinedRequests = [
    {
        contents: [{
            parts: [{text: 'Tell me a one-sentence joke.'}],
            role: 'user'
        }]
    },
    {
        contents: [{
            parts: [{'text': 'Why is the sky blue?'}],
            role: 'user'
        }]
    }
]

const response = await ai.batches.create({
    model: 'gemini-3.7-flash',
    src: inlinedRequests,
    config: {
        displayName: 'inlined-requests-job-1',
    }
});

console.log(response);

REST

curl https://generativelanguage.googleapis.com/v1beta/models/gemini-3.7-flash:batchGenerateContent \
-H "x-goog-api-key: $GEMINI_API_KEY" \
-X POST \
-H "Content-Type:application/json" \
-d '{
    "batch": {
        "display_name": "my-batch-requests",
        "input_config": {
            "requests": {
                "requests": [
                    {
                        "request": {"contents": [{"parts": [{"text": "Describe the process of photosynthesis."}]}]},
                        "metadata": {
                            "key": "request-1"
                        }
                    },
                    {
                        "request": {"contents": [{"parts": [{"text": "Describe the process of photosynthesis."}]}]},
                        "metadata": {
                            "key": "request-2"
                        }
                    }
                ]
            }
        }
    }
}'

Input file

For larger sets of requests, prepare a JSON Lines (JSONL) file. Each line in this file must be a JSON object containing a user-defined key and a request object, where the request is a valid GenerateContentRequest object. The user-defined key is used in the response to indicate which output is the result of which request. For example, the request with the key defined as request-1 will have its response annotated with the same key name.

This file is uploaded using the File API. The maximum allowed file size for an input file is 2GB.

The following is an example of a JSONL file. You can save it in a file named my-batch-requests.json:

{"key": "request-1", "request": {"contents": [{"parts": [{"text": "Describe the process of photosynthesis."}]}], "generation_config": {"temperature": 0.7}}}
{"key": "request-2", "request": {"contents": [{"parts": [{"text": "What are the main ingredients in a Margherita pizza?"}]}]}}

Similarly to inline requests, you can specify other parameters like system instructions, tools or other configurations in each request JSON.

You can upload this file using the File API as shown in the following example. If you are working with multimodal input, you can reference other uploaded files within your JSONL file.

Python


import json
from google import genai
from google.genai import types

client = genai.Client()

# Create a sample JSONL file
with open("my-batch-requests.jsonl", "w") as f:
    requests = [
        {"key": "request-1", "request": {"contents": [{"parts": [{"text": "Describe the process of photosynthesis."}]}]}},
        {"key": "request-2", "request": {"contents": [{"parts": [{"text": "What are the main ingredients in a Margherita pizza?"}]}]}}
    ]
    for req in requests:
        f.write(json.dumps(req) + "\n")

# Upload the file to the File API
uploaded_file = client.files.upload(
    file='my-batch-requests.jsonl',
    config=types.UploadFileConfig(display_name='my-batch-requests', mime_type='jsonl')
)

print(f"Uploaded file: {uploaded_file.name}")

JavaScript


import {GoogleGenAI} from '@google/genai';
import * as fs from "fs";
import * as path from "path";
import { fileURLToPath } from 'url';

const ai = new GoogleGenAI({});
const fileName = "my-batch-requests.jsonl";

// Define the requests
const requests = [
    { "key": "request-1", "request": { "contents": [{ "parts": [{ "text": "Describe the process of photosynthesis." }] }] } },
    { "key": "request-2", "request": { "contents": [{ "parts": [{ "text": "What are the main ingredients in a Margherita pizza?" }] }] } }
];

// Construct the full path to file
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const filePath = path.join(__dirname, fileName); // __dirname is the directory of the current script

async function writeBatchRequestsToFile(requests, filePath) {
    try {
        // Use a writable stream for efficiency, especially with larger files.
        const writeStream = fs.createWriteStream(filePath, { flags: 'w' });

        writeStream.on('error', (err) => {
            console.error(`Error writing to file ${filePath}:`, err);
        });

        for (const req of requests) {
            writeStream.write(JSON.stringify(req) + '\n');
        }

        writeStream.end();

        console.log(`Successfully wrote batch requests to ${filePath}`);

    } catch (error) {
        // This catch block is for errors that might occur before stream setup,
        // stream errors are handled by the 'error' event.
        console.error(`An unexpected error occurred:`, error);
    }
}

// Write to a file.
writeBatchRequestsToFile(requests, filePath);

// Upload the file to the File API.
const uploadedFile = await ai.files.upload({file: 'my-batch-requests.jsonl', config: {
    mimeType: 'jsonl',
}});
console.log(uploadedFile.name);

REST

tmp_batch_input_file=batch_input.tmp
echo -e '{"contents": [{"parts": [{"text": "Describe the process of photosynthesis."}]}], "generationConfig": {"temperature": 0.7}}\n{"contents": [{"parts": [{"text": "What are the main ingredients in a Margherita pizza?"}]}]}' > batch_input.tmp
MIME_TYPE=$(file -b --mime-type "${tmp_batch_input_file}")
NUM_BYTES=$(wc -c < "${tmp_batch_input_file}")
DISPLAY_NAME=BatchInput

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 "https://generativelanguage.googleapis.com/upload/v1beta/files" \
-D "${tmp_header_file}" \
-H "x-goog-api-key: $GEMINI_API_KEY" \
-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: ${MIME_TYPE}" \
-H "Content-Type: application/jsonl" \
-d "{'file': {'display_name': '${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: ${NUM_BYTES}" \
-H "X-Goog-Upload-Offset: 0" \
-H "X-Goog-Upload-Command: upload, finalize" \
--data-binary "@${tmp_batch_input_file}" 2> /dev/null > file_info.json

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

The following example calls the BatchGenerateContent method with the input file uploaded using File API:

Python

from google import genai

# Assumes `uploaded_file` is the file object from the previous step
client = genai.Client()
file_batch_job = client.batches.create(
    model="gemini-3.7-flash",
    src=uploaded_file.name,
    config={
        'display_name': "file-upload-job-1",
    },
)

print(f"Created batch job: {file_batch_job.name}")

JavaScript

// Assumes `uploadedFile` is the file object from the previous step
const fileBatchJob = await ai.batches.create({
    model: 'gemini-3.7-flash',
    src: uploadedFile.name,
    config: {
        displayName: 'file-upload-job-1',
    }
});

console.log(fileBatchJob);

REST

# Set the File ID taken from the upload response.
BATCH_INPUT_FILE='files/123456'
curl https://generativelanguage.googleapis.com/v1beta/models/gemini-3.7-flash:batchGenerateContent \
-X POST \
-H "x-goog-api-key: $GEMINI_API_KEY" \
-H "Content-Type:application/json" \
-d "{
    'batch': {
        'display_name': 'my-batch-requests',
        'input_config': {
            'file_name': '${BATCH_INPUT_FILE}'
        }
    }
}"

When you create a batch job, you will get a job name returned. Use this name for monitoring the job status as well as retrieving the results once the job completes.

The following is an example output that contains a job name:


Created batch job from file: batches/123456789

Batch embedding support

You can use the Batch API to interact with the Embeddings model for higher throughput. To create an embeddings batch job with either inline requests or input files, use the batches.create_embeddings API and specify the embeddings model.

Python

from google import genai

client = genai.Client()

# Creating an embeddings batch job with an input file request:
file_job = client.batches.create_embeddings(
    model="gemini-embedding-2",
    src={'file_name': uploaded_batch_requests.name},
    config={'display_name': "Input embeddings batch"},
)

# Creating an embeddings batch job with an inline request:
batch_job = client.batches.create_embeddings(
    model="gemini-embedding-2",
    # For a predefined list of requests `inlined_requests`
    src={'inlined_requests': inlined_requests},
    config={'display_name': "Inlined embeddings batch"},
)

JavaScript

// Creating an embeddings batch job with an input file request:
let fileJob;
fileJob = await client.batches.createEmbeddings({
    model: 'gemini-embedding-2',
    src: {fileName: uploadedBatchRequests.name},
    config: {displayName: 'Input embeddings batch'},
});
console.