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Claude Sonnet 4

invited beta chatCodeReasoningTool calling

Anthropic Sonnet 4: balanced model for coding and everyday agentic tasks.

Input
$3/M
Output
$15/M
Cache read
$0.3/M
Context
200K
vs GPT-4o
~40% cheaper

Benchmarks

Claude Sonnet 4: 57 published, but no benchmark it shares with enough other models to compare.

Claude Sonnet 4 other models measured peer average no peer scored higher
EmbSpatialBench no thinking
67.5%
AI2D (test) no thinking
82.6%

Vendor-published: Alibaba (Qwen)

Price in context

Where the price sits among 60 comparable models

Input$3/M
$0.05 · Qwen3 VL Flash GPT-5.4 Pro · $30
Output$15/M
$0.275 · DeepSeek V4 Flash GPT-5.4 Pro · $180
Cached read$0.3/M
$0.0028 · DeepSeek V4 Flash GPT-5.4 Pro · $15

The bar shows how this model’s price compares with every other model of the same kind on Synthorai. The cheapest and the most expensive are named at each end. These are base rates; batch, region and cache-write discounts are on the pricing page.

Specs & limits

Prompt caching

How it caches explicit (opt-in)
Min prefix 1,024
Lifetime 5m default, 1h option
Write cost 1.25x (5m) / 2x (1h)

Use Claude Sonnet 4 in 30 seconds

OpenAI-compatible: swap the base_url, keep your SDK. POST /v1/chat/completions

from openai import OpenAI

client = OpenAI(
    base_url="https://synthorai.io/v1",
    api_key="sk-syn-...",
)

resp = client.chat.completions.create(
    model="claude-sonnet-4",
    messages=[{"role": "user", "content": "Summarize this diff"}],
    reasoning_effort="medium",
)
print(resp.choices[0].message.content)

FAQ

Is the Claude Sonnet 4 API free to try?

Claude Sonnet 4 is currently in invited beta: access is application-based rather than open signup. Apply from the Synthorai console; once approved, standard pay-as-you-go pricing applies with no subscription.

How much does Claude Sonnet 4 cost?

Claude Sonnet 4 costs $3 per million input tokens and $15 per million output tokens on Synthorai. That is the provider's list price, with no platform markup. Cached input tokens bill at $0.3/M.

Does Claude Sonnet 4 support prompt caching?

Yes, via opt-in: mark stable prefixes with cache_control breakpoints. Cached input tokens bill at $0.3/M vs $3/M uncached; prompts need a 1,024-token stable prefix to cache (TTL 5m default, 1h option). Prompt caching guide →

How do I get access to Claude Sonnet 4?

Claude Sonnet 4 is in invited beta: request access from the Synthorai console. Once approved it works like every other model: point your OpenAI SDK at base_url="https://synthorai.io/v1" and set model="claude-sonnet-4".

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Every value on this page is transcribed from the vendor's own documentation, linked above, and carries the date it was checked. Prices are compared across the catalogue; specification values that vendors define differently are shown with the difference stated rather than charted. Nothing here is measured by us, and nothing is scored.

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