{"slug": "vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks", "title": "Vertex AI SDK Is Dead: Migrate to google-genai Before Your Code Breaks", "summary": "Google removed Vertex AI generative AI modules on June 24, 2026, breaking code that imports from deprecated paths like vertexai.generative_models. Developers must migrate to the google-genai SDK to fix production failures and unlock new models like Gemini 3.1 Pro.", "body_md": "If your service calls Gemini via `from vertexai.generative_models import GenerativeModel`\n\n, it broke two days ago. Google removed the Vertex AI generative AI modules on June 24 — exactly one year after announcing the deprecation. No grace period, no compatibility shim. The fix is a three-step migration that takes under an hour, and it unlocks Gemini 3.1 Pro as a bonus since that model is not available on the old SDK at all.\n\n## What Was Removed\n\nFive module paths are gone as of June 24, 2026. If your code imports from any of these, you’re getting an `ImportError`\n\nor `AttributeError`\n\nin production right now:\n\n`vertexai.generative_models`\n\n— the big one.`GenerativeModel`\n\n,`Part`\n\n,`Content`\n\n, and`HarmCategory`\n\nall lived here.`vertexai.language_models`\n\n—`TextGenerationModel`\n\n,`ChatModel`\n\n`vertexai.vision_models`\n\n—`ImageGenerationModel`\n\n`vertexai.tuning`\n\n— fine-tuning jobs`vertexai.caching`\n\n— context caching\n\nRun this before anything else to find every affected file:\n\n```\ngrep -r \"vertexai.generative_models\" .\n```\n\nEvery match is a live production failure. Repeat for the other module names above.\n\n## The Fix in Three Steps\n\nThe replacement is the [Google Gen AI SDK](https://github.com/googleapis/python-genai) (`google-genai`\n\n). Install it, then swap two patterns in your code.\n\n**Step 1: Install the new SDK**\n\n```\npip install google-genai\n```\n\n**Step 2: Replace the old initialization and call pattern.** Here is what your code looks like now (broken):\n\n``` python\nfrom vertexai.generative_models import GenerativeModel\nimport vertexai\n\nvertexai.init(project=\"my-project\", location=\"us-central1\")\nmodel = GenerativeModel(\"gemini-2.0-flash\")\nresponse = model.generate_content(\"Summarize this:\")\nprint(response.text)\n```\n\nHere is what it should look like after migration:\n\n``` python\nfrom google import genai\nfrom google.genai.types import HttpOptions\n\nclient = genai.Client(\n    vertexai=True,\n    project=\"my-project\",\n    location=\"us-central1\",\n    http_options=HttpOptions(api_version=\"v1\"),\n)\nresponse = client.models.generate_content(\n    model=\"gemini-2.0-flash\",\n    contents=\"Summarize this:\",\n)\nprint(response.text)\n```\n\n**Step 3: Update streaming calls** if you use them:\n\n```\nfor chunk in client.models.generate_content_stream(\n    model=\"gemini-2.0-flash\",\n    contents=\"Tell me a story\",\n):\n    print(chunk.text, end=\"\")\n```\n\n## What Actually Changed Under the Hood\n\nThe old SDK used global module-level state. You called `vertexai.init()`\n\nonce and every subsequent `GenerativeModel`\n\ncall inherited your project and location silently. That worked until you needed multiple clients, different regions, or proper test isolation — at which point it became a liability.\n\nThe new SDK is client-based. All config lives on the `Client`\n\nobject. It is explicit, thread-safe, and actually testable. This is the same direction OpenAI took with their Python SDK, and Google is right to follow.\n\nOne gotcha worth calling out: `GenerateContentResponse`\n\nobjects are now Pydantic models. If you call `.to_dict()`\n\non a response object, that breaks too. Replace it:\n\n```\n# Old (broken)\nresponse_dict = response.to_dict()\n\n# New\nresponse_dict = response.model_dump(mode='json')\n```\n\n## You Also Unlock Gemini 3.1 Pro\n\nThis migration is not purely defensive. Vertex AI SDK releases after June 2026 do not support new Gemini models at all — they are exclusive to `google-genai`\n\n. [Gemini 3.1 Pro](https://cloud.google.com/blog/products/ai-machine-learning/gemini-3-1-pro-on-gemini-cli-gemini-enterprise-and-vertex-ai), released this month, scored 77.1% on the ARC-AGI-2 benchmark and delivers double the reasoning performance of 3 Pro. You can only reach it through the new SDK:\n\n```\nresponse = client.models.generate_content(\n    model=\"gemini-3-1-pro\",\n    contents=\"Your prompt here\",\n)\n```\n\n## Framework Users: Check Your Wrappers\n\nIf you’re using LangChain, upgrade to `langchain-google-genai`\n\n4.0.0 — that release migrated the package to the unified google-genai SDK internally. You’ll switch from `ChatVertexAI`\n\nto `ChatGoogleGenerativeAI`\n\nfor Gemini calls. One real-world catch: the old wrapper used gRPC for transport. The new one defaults to REST. If you run high-throughput streaming, benchmark before flipping to production — some teams have reported latency differences on real-time workloads.\n\nFor Java, the LangChain4j [migration is tracked in issue #4383](https://github.com/langchain4j/langchain4j/issues/4383) — check your wrapper version before assuming it has been handled automatically.\n\n## Verification Checklist\n\n`pip show google-genai`\n\nconfirms the package is installed- Searching codebase for\n`vertexai.generative_models`\n\nreturns zero results `client.models.list()`\n\nreturns available models without error- A test\n`generate_content()`\n\ncall returns`.text`\n\nas expected - Streaming tested with\n`generate_content_stream()`\n\nif your app uses it\n\nThe migration is not optional and there is no rollback path. But it is also not complex — the API surface maps almost one-to-one, and the code you end up with is meaningfully cleaner. The biggest operational risk is not the migration itself; it is discovering the failure in a production incident rather than a planned deploy. Run the search now, migrate today, and use the new model IDs while you’re at it. Google’s [official migration guide](https://cloud.google.com/vertex-ai/generative-ai/docs/deprecations/genai-vertexai-sdk) covers edge cases including async clients, embeddings, and multimodal content.", "url": "https://wpnews.pro/news/vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks", "canonical_source": "https://byteiota.com/vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks/", "published_at": "2026-06-26 08:12:54+00:00", "updated_at": "2026-06-26 08:39:57.882079+00:00", "lang": "en", "topics": ["ai-tools", "developer-tools", "large-language-models"], "entities": ["Google", "Vertex AI", "Gemini", "Gemini 3.1 Pro", "LangChain", "OpenAI"], "alternates": {"html": "https://wpnews.pro/news/vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks", "markdown": "https://wpnews.pro/news/vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks.md", "text": "https://wpnews.pro/news/vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks.txt", "jsonld": "https://wpnews.pro/news/vertex-ai-sdk-is-dead-migrate-to-google-genai-before-your-code-breaks.jsonld"}}