Chat with a Google Gemini or Vertex AI model

Google's AI offering is broken up into two parts: Gemini and Vertex AI. Most enterprises are likely to use Vertex AI, and individuals are likely to use Gemini.

Use google_upload() to upload files (PDFs, images, video, audio, etc.)

Authentication

By default, chat_google_gemini() will use Google's default application credentials if there is no API key provided. This requires the gargle package.

It can also pick up on viewer-based credentials on Posit Connect. This in turn requires the connectcreds package.

chat_google_gemini(
  system_prompt = NULL,
  base_url = "https://generativelanguage.googleapis.com/v1beta/",
  api_key = NULL,
  model = NULL,
  params = NULL,
  api_args = list(),
  echo = NULL
)

chat_google_vertex(
  location,
  project_id,
  system_prompt = NULL,
  model = NULL,
  params = NULL,
  api_args = list(),
  echo = NULL
)

models_google_gemini(
  base_url = "https://generativelanguage.googleapis.com/v1beta/",
  api_key = NULL
)

models_google_vertex(location, project_id)

Arguments

system_prompt

A system prompt to set the behavior of the assistant.

base_url

The base URL to the endpoint; the default uses OpenAI.

api_key

API key to use for authentication.

You generally should not supply this directly, but instead set the GOOGLE_API_KEY environment variable. The best place to set this is in .Renviron, which you can easily edit by calling usethis::edit_r_environ(). For Gemini, you can alternatively set GEMINI_API_KEY.

model

The model to use for the chat (defaults to "gemini-2.0-flash"). We regularly update the default, so we strongly recommend explicitly specifying a model for anything other than casual use. Use models_google_gemini() to see all options.

params

Common model parameters, usually created by params().

api_args

Named list of arbitrary extra arguments appended to the body of every chat API call. Combined with the body object generated by ellmer with modifyList().

echo

One of the following options:

• none: don't emit any output (default when running in a function).

• text: echo text output as it streams in (default when running at the console).

• all: echo all input and output.

Note this only affects the chat() method.

location

Location, e.g. us-east1, me-central1, africa-south1.

project_id

Project ID.

Value

A Chat object.

See also

Other chatbots: chat_anthropic(), chat_aws_bedrock(), chat_azure_openai(), chat_cloudflare(), chat_cortex_analyst(), chat_databricks(), chat_deepseek(), chat_github(), chat_groq(), chat_huggingface(), chat_mistral(), chat_ollama(), chat_openai(), chat_openrouter(), chat_perplexity(), chat_portkey()

Examples

if (FALSE) { # \dontrun{
chat <- chat_google_gemini()
chat$chat("Tell me three jokes about statisticians")
} # }