Does new interaction API support vertex ai?

[danhnguyen8391]

I tried interaction API with vertex ai but get error 404. For the same code, I try with AI studio API key, it works. Seem like this new API does still not support vertex ai?

[adk-bot]

Response from ADK Answering Agent (experimental, answer may be inaccurate)

TLDR: Yes, the Interaction API supports Vertex AI, but it requires a different configuration than the AI Studio API key. The 404 error you're seeing is likely due to an authentication or configuration issue. Please ensure you have authenticated for Vertex AI and set the correct environment variables.

---

Hello! Thanks for your question.

The ADK is designed to work with both the Gemini API (used by AI Studio) and the Vertex AI API. However, they use different authentication and configuration setups, which is likely the cause of the 404 error you are encountering.

Here are the key differences and steps to ensure your environment is set up correctly for Vertex AI:

1. Authentication:

   • AI Studio uses an API key (GOOGLE_API_KEY).
   • Vertex AI uses your Google Cloud user credentials. You must authenticate by running this command in your terminal:

     gcloud auth application-default login

2. Environment Variables: To tell the ADK to use Vertex AI instead of the Gemini API, you must set the following environment variable. [1, 2]

   export GOOGLE_GENAI_USE_VERTEXAI=TRUE

By default, if GOOGLE_GENAI_USE_VERTEXAI is not set or is FALSE, the ADK will attempt to use the Gemini API with an API key. [2, 3]

To resolve the 404 error, please verify that you have:

• Run gcloud auth application-default login successfully.
• Set GOOGLE_GENAI_USE_VERTEXAI to TRUE in your environment.
• Ensured that your Google Cloud project has the Vertex AI API enabled.

Following these steps should correctly configure the ADK to use your Vertex AI setup. Let us know if you continue to experience issues.

[1] https://google.github.io/adk-docs/streaming/dev-guide/part1/
[2] https://google.github.io/adk-docs/agents/config/
[3] https://google.github.io/adk-docs/get-started/quickstart/

[danhnguyen8391]

My vertex ai service account still works well when I use generated content API that means the setup is not a problem. It only does not work when I use interaction API.

[patrickloeber]

Hi, Patrick here from the Gemini API team. No, the Interaction API is currently not available in Vertex AI. It's in our roadmap, we expect to bring Interactions API to VertexAI in the next couple of months.

[tokrex]

Hey Patrick, was very happy to find your post 10 hours ago, because i want to use google's new interactions api (especially with store=true) in our rust backends... tell me how i should explain my CFO and CTO this? We the model options 'lyria-3' we can now only make music ;D i think my management like to hear, that we can now generate cool house and hip hop music with Google's Enterprise Platform ;D better sing agent responses to your customers ~ text is just boring ;D they will love it... in other words if we dont want to use 'deep-research-preview-04-2026' (never tried it, but it's sandboxed and eats i guess more resources)... we stay with :streamGenerateContent endpoints... but hey, interactions api was so promising.. it's a bit sad. especially the lyria-3 option.. i think it's a joke ;D the doc team of gemini just made a mistake here... right? i am sure ;D

[selvabalaji-prudentai]

Hi, Interactions API is available now: https://docs.cloud.google.com/gemini-enterprise-agent-platform/reference/models/interactions-api

from google import genai
from google.genai import types

client = genai.Client(vertexai=True, location='global')
interaction = client.interactions.create(...)

Note that the Gemini Enterprise Agent Platform still has the Interactions API in experimental state, while Gemini API has it as GA now.

Hi @patrickloeber,

Thanks for the update. I tried the Vertex AI Interactions API again using the latest google-genai SDK, but I'm still running into the same issue.

Using an API key works as expected:

client = genai.Client(api_key=GEMINI_API_KEY)
interaction = client.interactions.create(model="gemini-3.5-flash", ...)

However, when I use Vertex AI with a service account:

client = genai.Client(
vertexai=True,
project="nonprod-shared-local-dev",
location="global",
)

(with GOOGLE_APPLICATION_CREDENTIALS pointing to a valid service account), the same call fails with:

BadRequestError: Error code: 400
Unsupported model interaction: gemini-3.5-flash

generate_content() works fine with the same Vertex AI client, so authentication and project configuration appear to be correct. The issue seems to be specific to the Interactions API.

Our production environment uses Vertex AI with service accounts for IAM, billing, and auditability, so using an API key isn't an option for us.

Could you clarify:

Is the Interactions API fully supported on Vertex AI today, or is support still limited/experimental?
Is there any additional project configuration or feature enablement required?
If this isn't supported yet, do you have an estimated timeline for GA support on Vertex AI?

Thanks!

[markrubio-TU]

Hey Patrick, was very happy to find your post 10 hours ago, because i want to use google's new interactions api (especially with store=true) in our rust backends... tell me how i should explain my CFO and CTO this? We the model options 'lyria-3' we can now only make music ;D i think my management like to hear, that we can now generate cool house and hip hop music with Google's Enterprise Platform ;D better sing agent responses to your customers ~ text is just boring ;D they will love it... in other words if we dont want to use 'deep-research-preview-04-2026' (never tried it, but it's sandboxed and eats i guess more resources)... we stay with :streamGenerateContent endpoints... but hey, interactions api was so promising.. it's a bit sad. especially the lyria-3 option.. i think it's a joke ;D the doc team of gemini just made a mistake here... right? i am sure ;D

LOL made my day. made me laugh. it's just so sad that Vertex AI IS SUPPOSED TO BE AN ENTERPRISE OFFERING but the very basic functionality doesn't work. LOL

Addendum: even this documentation looks to be outdated? https://docs.cloud.google.com/gemini-enterprise-agent-platform/build/managed-agents/interact-with-agents. It says here it is supposed to support antigravity-preview-05-2026. but everytime I try I get a not-so-helpful 500 status code with just api_error?

[majinken1026]

I'm also anxiously awaiting an update on this issue. I would like to use Interactions API on Vertex using Gemini 3 series model.

[tapashray]

Same here, this api seems easier to use instead of generate_content() and send_message() and having to recreate the chat history. Surprisingly the documentation also doesn't indicate this gap anywhere