Model · Anthropic

Claude Sonnet 5.5

Claude Sonnet 5.5 is served by Anthropic through OpenRouter. It provides 1M tokens of context and supports text, vision, files inputs.

Snapshot 2026-10-10 anthropic/claude-sonnet-5.5

Context window

1M tokens

Input / 1M tokens

$2.00

Output / 1M tokens

$10.00

Key facts

Provider	Anthropic
OpenRouter ID	`anthropic/claude-sonnet-5.5`
Modalities	Text, Vision, Files
Best for	Overall, Coding, Agents

Source openrouter.ai/api/v1/models Verified 2026-10-10 Drift-checked daily 06:00 CST

Best-fit workloads

Best overall

Strong reasoning, tooling and production reliability.

Best for coding

Good code quality, debugging and technical explanation.

Best for agents

Tool use, structured output and multi-step reasoning.

Cost estimates

These examples use the 2026-10-10 input and output prices. Cache discounts, provider surcharges and tool fees are excluded.

Workload	Input	Output	Estimated cost
Quick test	20,000	5,000	$0.090
Product chat month	500,000	125,000	$2.25
Document batch	5,000,000	1,000,000	$20.00

Strengths

✓ $2 / $10 per million with a 1M-token window — the balanced tier most product teams land on
✓ Positioned as a direct upgrade to Sonnet 5 for building features and fixing bugs
✓ Cached input at $0.10 per million, a tenth of the input price

Limitations

! Text output only
! The window is the same 1M as Opus 5.5, so the reason to pay 2x is output quality rather than size
! Half the price of Opus 5.5 and twenty times the price of Haiku 5.5: the middle of this line is where the real decision is

OpenRouter API quickstart

Run these examples from your server or edge function. Keep the OpenRouter API key private and do not expose it in browser code.

cURL

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-5.5",
    "messages": [{ "role": "user", "content": "Summarize this document in five bullet points." }],
    "max_tokens": 500
  }'

JavaScript / TypeScript

const response = await fetch("https://openrouter.ai/api/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.OPENROUTER_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "anthropic/claude-sonnet-5.5",
    messages: [{ role: "user", content: "Summarize this document in five bullet points." }],
    max_tokens: 500,
  }),
});

const data = await response.json();
console.log(data.choices[0].message.content);

How to evaluate Claude Sonnet 5.5

Run five real tasks from your product, not generic demo prompts.
Record token usage, latency and output quality.
Estimate cost using your real input/output mix.
Compare it against one model with a similar price and one stronger model.

Compare models View on OpenRouter ↗

Claude Sonnet 5.5 FAQ

What is Claude Sonnet 5.5?

Claude Sonnet 5.5 is a Anthropic model available through OpenRouter. It supports text, vision, files inputs and is suited for overall, coding, agents workloads.

How much does Claude Sonnet 5.5 cost on OpenRouter?

The 2026-10-10 snapshot lists $2.00 per 1M input tokens and $10.00 per 1M output tokens. Verify current pricing on OpenRouter before production.

How large is Claude Sonnet 5.5's context window?

Claude Sonnet 5.5 offers 1M tokens of context in the current snapshot. Provider-specific limits and surcharges may apply.

Head-to-head comparisons

Claude Sonnet 5.5 vs GPT-6.1 Sol

There is no price argument here, which makes it a rare clean A/B: run your own prompts through both and pick on output. The catalogue's own positioning says Sonnet 5.5 is for well-scoped everyday work and GPT-6.1 Sol for agentic coding and document-heavy professional work — that is a hint about the intended shape of the workload, not a benchmark.

Claude Opus 5.5 vs Claude Sonnet 5.5

Inside one family the choice is unusually clean: you are buying the top tier of the same line, and the cliff between them is the point of the lineup. Route the hard 10% of tasks to Opus and the other 90% to Sonnet, and you cut the bill while keeping the ceiling — providing your routing is better than a coin flip.

Pricing and context data are based on a 2026-10-10 snapshot. Provider limits can change; always verify on OpenRouter before production.