Claude Sonnet 4.5
Claude Sonnet 4.5 on Zumik: live pricing, context, and caching, routable by id or alias through one OpenAI-compatible endpoint.
At a glance.
| Provider | Anthropic |
| Family | claude-sonnet |
| Released | 2025-09 |
| License | Proprietary |
| Context window | 200K tokens |
| Max output | 64K tokens |
| Modalities | text, image, pdf |
| Tool calling | Yes |
| Reasoning mode | Yes |
| Caching | explicit |
| Batch discount | 50% off |
What reuse looks like here.
Pricing, context, and capabilities for Claude Sonnet 4.5 are live, but it is outside the flagship set Zumik benchmarks in depth, so measured reuse, capture, and warm TTFT are not shown yet. Run a workload estimate or route it by id to start collecting traces.
What you actually pay once caching works.
At a typical 55% prefix reuse, a million input tokens on Claude Sonnet 4.5 effectively costs $1.51 instead of $3.00 - blending to roughly $4.89 with a 25% output share. Background work drops a further 50% on the batch tier.
Estimate it for your workloadRoute it directly by id, or let an alias pick it when it wins under policy.
Same OpenAI client, this model.
from openai import OpenAI
client = OpenAI(base_url="https://api.zumik.ai/v1", api_key="zk_live_...")
r = client.responses.create(
model="claude-sonnet-4-5-20250929",
input="Draft a fix for the failing test.",
)
print(r.usage.input_tokens_cached) # confirm reuseClaude Sonnet 4.5, answered.
How much does Claude Sonnet 4.5 cost?
Claude Sonnet 4.5 is $3.00 per million input tokens and $15.00 per million output tokens through Zumik. Cache reads are $0.30 per million, a 90% discount on input.
What is Claude Sonnet 4.5's context window?
Claude Sonnet 4.5 supports a 200K-token context window with up to 64K output tokens.
Run Claude Sonnet 4.5 with reuse measured.
Point an OpenAI client at Zumik and see exactly how much of this model's input you are reusing.