LLM Perks

Claude Sonnet 5

Anthropic · All Claude models
Free right now Frontier New
VisionCodingTool useLong context

Claude Sonnet 5 is a language model from Anthropic. It is currently free at 1 provider with up to 1M tokens of context. The model understands images, is suited to coding, supports tool calling.

Developer
Anthropic
Context
1M tokens
Type
Text
License
Proprietary
Free since
October 13, 2026

Where to use Claude Sonnet 5 for free

Each row is a separate free endpoint with its own limits.

ProviderContextLimitCard
UnoRouter
claude-sonnet-5:free
1M No-card free models use shared capacity and per-model limits; availability can change. No Open

Quick start

curl https://api.unorouter.com/v1/chat/completions \
  -H "Authorization: Bearer $UNOROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-5:free",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Example for UnoRouter. Any OpenAI-compatible client works: Cursor, Cline, OpenCode, Open WebUI.

Benchmarks

Intelligence Index
38.2
GPQA Diamond
91.1%
Humanity's Last Exam
41.3%
Long context (LCR)
82.0%

Source: Artificial Analysis · Claude Sonnet 5 (Max)

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FAQ

Is Claude Sonnet 5 free?

Yes. As of October 13, 2026, Claude Sonnet 5 is free at UnoRouter. Each provider has its own limits — see the table above.

What is the context window of Claude Sonnet 5?

The largest context among free routes is 1,000,000 tokens. Some providers cap it lower.

How do I call Claude Sonnet 5 via API?

Use any OpenAI-compatible client with base URL https://api.unorouter.com/v1, model ID claude-sonnet-5:free, and a UnoRouter key.

How good is Claude Sonnet 5?

Artificial Analysis Intelligence Index: 38.2, GPQA Diamond: 91%. For comparison, the strongest free model in the catalog right now is Claude Opus 5.5.

Is Claude Sonnet 5 open-weight?

No, it is proprietary: access is only through provider APIs.