Text generation

The Gemini API can generate text output from text, images, video, and audio inputs.

Here's a basic example:

Python

from google import genai

client = genai.Client()

interaction = client.interactions.create(
    model="gemini-3.5-flash",
    input="How does AI work?"
)
print(interaction.output_text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const interaction = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "How does AI work?",
  });
  console.log(interaction.output_text);
}

await main();

REST

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "How does AI work?"
  }'

The Google GenAI SDKs provide convenience properties directly on the returned Interaction object to access the model's response.

The most common helper is interaction.output_text (String), which returns the last text blocks in the model's response. If the response is split across multiple consecutive TextContent blocks, it automatically joins them. Note that .output_text does not include earlier text blocks separated by non-text content (such as thoughts, images, audio, or tool calls). For complex or interleaved multimodal responses, you must manually iterate over steps instead. To learn more about other media convenience properties, see the Interactions overview.

Thinking with Gemini

Gemini models often have "thinking" enabled by default which allows the model to reason before responding to a request.

Each model supports different thinking configurations which gives you control over cost, latency, and intelligence. For more details, see the thinking guide.

Python

from google import genai

client = genai.Client()

interaction = client.interactions.create(
    model="gemini-3.5-flash",
    input="How does AI work?",
    generation_config={
        "thinking_level": "low"
    }
)
print(interaction.output_text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const interaction = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "How does AI work?",
    generation_config: {
      thinking_level: "low",
    },
  });
  console.log(interaction.output_text);
}

await main();

REST

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "How does AI work?",
    "generation_config": {
      "thinking_level": "low"
    }
  }'

System instructions and other configurations

You can guide the behavior of Gemini models with system instructions. Pass a system_instruction parameter to configure the model's behavior.

Python

from google import genai

client = genai.Client()

interaction = client.interactions.create(
    model="gemini-3.5-flash",
    system_instruction="You are a cat. Your name is Neko.",
    input="Hello there"
)

print(interaction.output_text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const interaction = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "Hello there",
    system_instruction: "You are a cat. Your name is Neko.",
  });
  console.log(interaction.output_text);
}

await main();

REST

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "system_instruction": "You are a cat. Your name is Neko.",
    "input": "Hello there"
  }'

You can also override default generation parameters, such as temperature, using the generation_config parameter.

Python

from google import genai

client = genai.Client()

interaction = client.interactions.create(
    model="gemini-3.5-flash",
    input="Explain how AI works",
    generation_config={
        "temperature": 1.0
    }
)
print(interaction.output_text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const interaction = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "Explain how AI works",
    generation_config: {
      temperature: 1.0,
    },
  });
  console.log(interaction.output_text);
}

await main();

REST

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "Explain how AI works",
    "generation_config": {
      "temperature": 1.0
    }
  }'

Refer to the Interactions API reference for a complete list of configurable parameters and their descriptions.

Multimodal inputs

The Gemini API supports multimodal inputs, allowing you to combine text with media files. The following example demonstrates providing an image:

Python

from google import genai

client = genai.Client()

uploaded_file = client.files.upload(file="path/to/organ.jpg")

interaction = client.interactions.create(
    model="gemini-3.5-flash",
    input=[
        {"type": "text", "text": "Tell me about this instrument"},
        {
            "type": "image",
            "uri": uploaded_file.uri,
            "mime_type": uploaded_file.mime_type
        }
    ]
)
print(interaction.output_text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const uploadedFile = await ai.files.upload({
    file: "path/to/organ.jpg",
    config: { mimeType: "image/jpeg" }
  });

  const interaction = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: [
      {type: "text", text: "Tell me about this instrument"},
      {
        type: "image",
        uri: uploadedFile.uri,
        mime_type: uploadedFile.mimeType
      }
    ],
  });
  console.log(interaction.output_text);
}

await main();

REST

# First upload the file using the Files API, then use the URI:
curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": [
      {"type": "text", "text": "Tell me about this instrument"},
      {
        "type": "image",
        "uri": "YOUR_FILE_URI",
        "mime_type": "image/jpeg"
      }
    ]
  }'

For alternative methods of providing images and more advanced image processing, see our image understanding guide. The API also supports document, video, and audio inputs and understanding.

Streaming responses

By default, the model returns a response only after the entire generation process is complete.

For more fluid interactions, use streaming to handle response chunks as they're generated. For a comprehensive guide covering event types, streaming with tools, thinking, agents, and image generation, see the dedicated Streaming interactions guide.

Python

from google import genai

client = genai.Client()

stream = client.interactions.create(
    model="gemini-3.5-flash",
    input="Explain how AI works",
    stream=True
)
for event in stream:
    if event.event_type == "step.delta":
        if event.delta.type == "text":
            print(event.delta.text, end="")

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const stream = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "Explain how AI works",
    stream: true,
  });

  for await (const event of stream) {
    if (event.event_type === "step.delta") {
      if (event.delta.type === "text") {
        process.stdout.write(event.delta.text);
      }
    }
  }
}

await main();

REST

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions?alt=sse" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  --no-buffer \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "Explain how AI works",
    "stream": true
  }'

Multi-turn conversations

The Interactions API supports multi-turn conversations by chaining interactions together using previous_interaction_id. Each turn is a separate interaction, and the API automatically manages conversation history.

Python

from google import genai

client = genai.Client()

interaction1 = client.interactions.create(
    model="gemini-3.5-flash",
    input="I have 2 dogs in my house.",
)
print(interaction1.output_text)

interaction2 = client.interactions.create(
    model="gemini-3.5-flash",
    input="How many paws are in my house?",
    previous_interaction_id=interaction1.id,
)
print(interaction2.output_text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const interaction1 = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "I have 2 dogs in my house.",
  });
  console.log("Response 1:", interaction1.output_text);

  const interaction2 = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "How many paws are in my house?",
    previous_interaction_id: interaction1.id,
  });
  console.log("Response 2:", interaction2.output_text);
}

await main();

REST

RESPONSE1=$(curl -s -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "I have 2 dogs in my house."
  }')

INTERACTION_ID=$(echo "$RESPONSE1" | jq -r '.id')

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "I have two dogs in my house. How many paws are in my house?",
    "previous_interaction_id": "'$INTERACTION_ID'"
  }'

Streaming can also be used for multi-turn conversations by combining previous_interaction_id with the streaming methods.

Python

from google import genai

client = genai.Client()

interaction1 = client.interactions.create(
    model="gemini-3.5-flash",
    input="I have 2 dogs in my house.",
)
print(interaction1.output_text)

stream = client.interactions.create(
    model="gemini-3.5-flash",
    input="How many paws are in my house?",
    previous_interaction_id=interaction1.id,
    stream=True
)
for event in stream:
    if event.event_type == "step.delta":
        if event.delta.type == "text":
            print(event.delta.text, end="")

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const interaction1 = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "I have 2 dogs in my house.",
  });
  console.log("Response 1:", interaction1.output_text);

  const stream = await ai.interactions.create({
    model: "gemini-3.5-flash",
    input: "How many paws are in my house?",
    previous_interaction_id: interaction1.id,
    stream: true,
  });
  for await (const event of stream) {
    if (event.event_type === "step.delta") {
      if (event.delta.type === "text") {
        process.stdout.write(event.delta.text);
      }
    }
  }
}

await main();

REST

RESPONSE1=$(curl -s -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "I have 2 dogs in my house."
  }')
INTERACTION_ID=$(echo "$RESPONSE1" | jq -r '.id')

curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions?alt=sse" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  --no-buffer \
  -d '{
    "model": "gemini-3.5-flash",
    "input": "How many paws are in my house?",
    "previous_interaction_id": "'$INTERACTION_ID'",
    "stream": true
  }'

Stateless conversations

By default, the Interactions API manages conversation state server-side when you use previous_interaction_id. However, you can also operate in stateless mode by managing the conversation history yourself on the client side.

To use stateless mode: 1. Set store=false in your request to opt out of server-side storage. 2. Maintain the conversation history as an array of steps on the client side. 3. In subsequent requests, pass the accumulated steps in the input field, and append your new turn as a user_input step.

Python

from google import genai

client = genai.Client()

history = [
    {
        "type": "user_input",
        "content": [{"type": "text", "text": "I have 2 dogs in my house."}]
    }
]

interaction1 = client.interactions.create(
    model="gemini-3.5-flash",
    store=False,
    input=history
)
print("Response 1:", interaction1.steps[-1].content[0].text)

for step in interaction1.steps:
    history.append(step.model_dump())

history.append({
    "type": "user_input",
    "content": [{"type": "text", "text": "How many paws are in my house?"}]
})

interaction2 = client.interactions.create(
    model="gemini-3.5-flash",
    store=False,
    input=history
)
print("Response 2:", interaction2.steps[-1].content[0].text)

JavaScript

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

const ai = new GoogleGenAI({});

async function main() {
  const history = [
    {
      type: "user_input",
      content: [{ type: "text", text: "I have 2 dogs in my house." }]
    }
  ];

  const interaction1 = await ai.interactions.create({
    model: "gemini-3.5-flash",
    store: false,
    input: history
  });
  console.log("Response 1:", interaction1.steps.at(-1).content[0].text);

  history.push(...interaction1.steps);

  history.push({
    type: "user_input",
    content: [{ type: "text", text: "How many paws are in my house?" }]
  });

  const interaction2 = await ai.interactions.create({
    model: "gemini-3.5-flash",
    store: false,
    input: history
  });
  console.log("Response 2:", interaction2.steps.at(-1).content[0].text);
}

await main();

REST

# Turn 1: Send request with store: false
RESPONSE1=$(curl -s -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d '{
    "model": "gemini-3.5-flash",
    "store": false,
    "input": [
      {
        "type": "user_input",
        "content": "I have 2 dogs in my house."
      }
    ]
  }')

# Extract the steps from response
MODEL_STEPS=$(echo "$RESPONSE1" | jq '.steps')

# Reconstruct the full history for Turn 2 by combining:
# 1. First user input
# 2. Model response steps
# 3. Second user input
HISTORY=$(jq -n \
  --argjson first_input '[{"type": "user_input", "content": "I have 2 dogs in my house."}]' \
  --argjson model_steps "$MODEL_STEPS" \
  --argjson second_input '[{"type": "user_input", "content": "How many paws are in my house?"}]' \
  "'"'"'$first_input + $model_steps + $second_input'"'"'")

# Turn 2: Send the full history
curl -X POST "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-api-key: $GEMINI_API_KEY" \
  -H 'Content-Type: application/json' \
  -H "Api-Revision: 2026-05-20" \
  -d "{
    \"model\": \"gemini-3.5-flash\",
    \"store\": false,
    \"input\": $HISTORY
  }"

Prompting tips

Consult our prompt engineering guide for suggestions on getting the most out of Gemini.

What's next