Anthropic: Claude Sonnet 4.5

Name: Claude Sonnet 4.5 API
Brand: Anthropic

stable

Claude Sonnet 4.5 is available through Everstack's OpenAI-compatible gateway with routing, fallback, retries, and observability.

claude-sonnet-4-5-20250929claude-4released Sep 29, 2025

Provider Quick start

Context

tokens

Max output

64K

tokens

Input

$3.00

per 1M

Output

$15.00

per 1M

Activity

Daily period usage

Aggregated managed Everstack traffic. Buckets below 5 tenants or 100 requests are withheld.

Providers

ProviderContextInput /MOutput /M

Anthropic

1M$3.00$15.00

Pricing

Item	Price	Unit
Input	$3.00	per 1M tokens
Output	$15.00	per 1M tokens
Cache read	$0.30	per 1M tokens
Cache write	$3.75	per 1M tokens

Performance

Reliability

Compare

Compare usage and performance

Place this model beside up to three other catalog models.

Capabilities

Modalities

Input

Output

Details

Model ID: claude-sonnet-4-5-20250929
Family: claude-4
Status: stable
Knowledge: -
Released: Sep 29, 2025

Gateway Config

API: 2023-06-01
Auth: ANTHROPIC_API_KEY
Discovery: static
Provider type: static

Quick Start

index.ts

import Everstack from "@everstack/node";const client = new Everstack({  apiKey: process.env.EVERSTACK_API_KEY!,  baseUrl: "https://{instance}.{region}.everstack.ai",});const completion = await client.chat.completions.create({  model: "@anthropic/claude-sonnet-4-5-20250929",  messages: [{ role: "user", content: "Explain vector cache routing." }],});console.log(completion.choices[0]?.message?.content);

Endpoint

Base URL

https://api.anthropic.com/v1

Chat completions

https://api.anthropic.com/v1/chat/completions

Model

claude-sonnet-4-5-20250929

Auth env

ANTHROPIC_API_KEY

Claude Sonnet 4.5 FAQ

How much does the Claude Sonnet 4.5 API cost?

Through Anthropic, Claude Sonnet 4.5 costs $3.00 per 1M input tokens and $15.00 per 1M output tokens.

What is the context window of Claude Sonnet 4.5?

Claude Sonnet 4.5 accepts up to 1M tokens of context and returns up to 64K output tokens on Anthropic.

What can Claude Sonnet 4.5 do?

Claude Sonnet 4.5 supports chat, function calling, image input, extended thinking and computer use. It accepts text, image and PDF input.

How do I call Claude Sonnet 4.5 through Everstack?

Point any OpenAI-compatible SDK at your Everstack gateway and set the model to @anthropic/claude-sonnet-4-5-20250929. Everstack adds retries, provider fallback, caching, per-tenant budgets and OpenTelemetry traces for every request.