Using Claude Sonnet 5.5 on GCP Vertex AI

Implementation guide · Claude 5.5 · Anthropic

Serverless

GCP Vertex AI exposes Claude Sonnet 5.5 through model ID claude-sonnet-5-5. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.

Last refreshed 2026-09-28. Next refresh: weekly.

Quick Start

  1. 1
    Create an account at GCP Vertex AI and generate an API key.
  2. 2
    Use the GCP Vertex AI SDK or REST API to call claude-sonnet-5-5 — see the documentation for request format.
  3. 3
    You'll be billed $2.00/1M input, $10.00/1M output tokens. See full pricing.

Code Examples

Install
pip install google-cloud-aiplatform
API key
GOOGLE_CLOUD_PROJECT
Model ID
claude-sonnet-5-5

For Google-published models use the model name directly, e.g. "gemini-2.0-flash-001". For third-party publishers (Anthropic, Meta, etc.) use the full publisher path, e.g. "publishers/anthropic/models/claude-3-5-sonnet-v2@20241022".

import os
import vertexai
from vertexai.generative_models import GenerativeModel

# Reads GOOGLE_CLOUD_PROJECT from env; authenticates via Application Default Credentials
vertexai.init(project=os.environ["GOOGLE_CLOUD_PROJECT"], location="us-central1")
model = GenerativeModel("claude-sonnet-5-5")
response = model.generate_content("Hello")
print(response.text)

Pricing on GCP Vertex AI

TypePrice (per 1M)
Input tokens$2.00
Output tokens$10.00

Capabilities

VisionMultimodalReasoningJSON / Tool useStructured OutputsPrompt CachingBatch API

About Claude Sonnet 5.5

Anthropic's Claude Sonnet 5.5, second model in the Claude 5.5 family, released September 28, 2026. First-party positioning: faster, lower-cost complement to Claude Opus 5.5; strongest at well-scoped everyday tasks, bug fixes, and polished documents/slides/spreadsheets; clear upgrade over Claude Sonnet 5 (30%+ faster output; up to 30% less cost per task via fewer tokens — list price unchanged vs Sonnet 5). Claude API id claude-sonnet-5-5. List price $2 per 1M input and $10 per 1M output; cache reads $0.20 / MTok; 5m cache writes $2.50; 1h cache writes $4; Batch API 50% off ($1/$5).

Model Specs

Released2026-09-28
Context1.05m
ArchitectureDecoder Only
Knowledge cutoff2026-06

Provider

GCP Vertex AI

Google Cloud Platform (GCP)

Mountain View, California, United States