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Access Google’s Generative AI models, including the Gemini family, directly via the Gemini API or experiment rapidly using Google AI Studio. The langchain-google-genai package provides the LangChain integration for these models. This is often the best starting point for individual developers. For information on the latest models, their features, context windows, etc. head to the Google AI docs. All model ids can be found in the Gemini API docs.

Integration details

Model features

Setup

To access Google AI models you’ll need to create a Google Account, get a Google AI API key, and install the langchain-google-genai integration package. 1. Installation:
2. Credentials: Head to https://ai.google.dev/gemini-api/docs/api-key (or via Google AI Studio) to generate a Google AI API key.

Chat Models

Use the ChatGoogleGenerativeAI class to interact with Google’s chat models. See the API reference for full details.
To enable automated tracing of your model calls, set your LangSmith API key:

Instantiation

Now we can instantiate our model object and generate chat completions:

Invocation

Chaining

We can chain our model with a prompt template like so:

Multimodal Usage

Gemini models can accept multimodal inputs (text, images, audio, video) and, for some models, generate multimodal outputs.

Image Input

Provide image inputs along with text using a HumanMessage with a list content format. Make sure to use a model that supports image input, such as gemini-2.5-flash.
Other supported image_url formats:
  • A Google Cloud Storage URI (gs://...). Ensure the service account has access.
  • A PIL Image object (the library handles encoding).

Audio Input

Provide audio file inputs along with text.

Video Input

Provide video file inputs along with text.

Image Generation (Multimodal Output)

Certain models (such as gemini-2.0-flash-preview-image-generation) can generate text and images inline. You need to specify the desired response_modalities. See more information on the Gemini API docs for details.
You can also use LangGraph to manage the conversation history for you as in this tutorial.

Tool Calling

You can equip the model with tools to call.

Structured Output

Force the model to respond with a specific structure using Pydantic models.

Token Usage Tracking

Access token usage information from the response metadata.

Built-in tools

Google Gemini supports a variety of built-in tools (google search, code execution), which can be bound to the model in the usual way.

Native Async

Use asynchronous methods for non-blocking calls.

Safety Settings

Gemini models have default safety settings that can be overridden. If you are receiving lots of “Safety Warnings” from your models, you can try tweaking the safety_settings attribute of the model. For example, to turn off safety blocking for dangerous content, you can construct your LLM as follows:
For an enumeration of the categories and thresholds available, see Google’s safety setting types.

API reference

For detailed documentation of all ChatGoogleGenerativeAI features and configurations head to the API reference.