claude-sonnet-5Claude Sonnet 5 is Anthropic's newest Sonnet — a 1M-token context window (both the default and the maximum; there is no smaller-context variant), up to 128K output tokens, adaptive thinking, and the same tools and platform features as Claude Sonnet 4.6 (Priority Tier is the one exception — Sonnet 5 does not support it). On API Models it's just $1 input / $4.5 output per 1M tokens, with prompt caching (cache reads at $0.1/M). Use it through the Anthropic Messages API (/v1/messages) — the native path for Claude Code, the Anthropic SDK, and Anthropic-compatible clients like Cursor — with native tool use (function calling). Request params match Claude Opus 4.8.
Default and maximum — no smaller variant
Extended reasoning when the task needs it
Long, complete responses in one call
Native tool use via the Anthropic Messages API
View complete API reference with all parameters and examples.
Enable real-time streaming responses with Server-Sent Events.
{
"model": "claude-sonnet-5",
"stream": true,
"max_tokens": 1024,
"messages": [...]
}Enable Claude to use tools and call functions.
{
"model": "claude-sonnet-5",
"max_tokens": 1024,
"tools": [{
"name": "get_weather",
"description": "Get current weather for a location",
"input_schema": {
"type": "object",
"properties": {
"location": {"type": "string", "description": "City name"}
},
"required": ["location"]
}
}],
"tool_choice": {"type": "auto"},
"messages": [{"role": "user", "content": "What's the weather in Tokyo?"}]
}Analyze PDF documents by sending them as base64 encoded content.
{
"model": "claude-sonnet-5",
"max_tokens": 1024,
"messages": [{
"role": "user",
"content": [{
"type": "document",
"source": {
"type": "base64",
"media_type": "application/pdf",
"data": "<base64_encoded_pdf>"
}
}, {
"type": "text",
"text": "Summarize this document."
}]
}]
}Get structured JSON responses that match your schema.
{
"model": "claude-sonnet-5",
"max_tokens": 1024,
"output_format": {
"type": "json_schema",
"schema": {
"type": "object",
"properties": {
"name": {"type": "string"},
"age": {"type": "integer"}
},
"required": ["name", "age"]
}
},
"messages": [{"role": "user", "content": "Extract info: John is 30 years old"}]
}Enable Claude to search the web for up-to-date information.
{
"model": "claude-sonnet-5",
"max_tokens": 1024,
"tools": [{
"type": "web_search_20250305",
"name": "web_search",
"max_uses": 5
}],
"messages": [{"role": "user", "content": "What's the latest news about AI?"}]
}| Parameter | Type | Required | Description |
|---|---|---|---|
| model | string | Yes | Model identifier (e.g., claude-sonnet-5) |
| messages | array | Yes | Array of message objects with role and content |
| max_tokens | integer | Yes | Maximum tokens in the response (1 - 128000) |
| system | string | No | System prompt to set context |
| stream | boolean | No | Enable streaming responses (SSE) |
| temperature | number | No | Sampling temperature (0.0 - 1.0) |
| top_p | number | No | Nucleus sampling threshold (0.0 - 1.0) |
| top_k | integer | No | Top-k sampling (0 - infinity) |
| stop_sequences | array | No | Sequences that stop generation |
| tools | array | No | Function calling tools definition |
| tool_choice | object | No | Tool selection strategy (auto/any/tool) |
| thinking | object | No | Enable extended thinking mode |
| output_format | object | No | Structured output with JSON schema |
View complete API reference with streaming, thinking, and more.
Billing: Cost = (input_tokens * input_price + output_tokens * output_price) / 1,000,000
Claude Sonnet 5 is a Large Language Model API provided by Anthropic. Claude Sonnet 5 is Anthropic's newest Sonnet — a 1M-token context window (both the default and the maximum; there is no smaller-context variant), up to 128K output tokens, adaptive thinking, and the same tools and platform features as Claude Sonnet 4.6 (Priority Tier is the one exception — Sonnet 5 does not support it). On API Models it's just $1 input / $4.5 output per 1M tokens, with prompt caching (cache reads at $0.1/M). Use it through the Anthropic Messages API (/v1/messages) — the native path for Claude Code, the Anthropic SDK, and Anthropic-compatible clients like Cursor — with native tool use (function calling). Request params match Claude Opus 4.8. Through API Models platform, you can access this model via a unified API with transparent pay-as-you-go pricing. Current pricing: Input: $1, Output: $4.5 per 1M tokens.
Build intelligent conversational systems to automatically answer user queries and improve service efficiency.
Automatically write articles, emails, ad copy, and other text content to boost productivity.
Assist with code writing, debugging, and code review to accelerate software development.
Understand and analyze unstructured data, extract key insights, and generate summary reports.
Claude Sonnet 5 is available through API Models at: Input: $1, Output: $4.5 per 1M tokens. Billing is pay-as-you-go — you only pay for what you generate.
Sign up at API Models, get your API key, and call our unified API endpoint. We provide detailed API documentation with code examples in cURL, Python, and Node.js.
API Models offers the same Claude Sonnet 5 model through our aggregation platform. We provide a unified API interface so you do not need separate accounts for each provider - one API key to access all models.
Claude Sonnet 5 is Anthropic's newest Sonnet model: a 1M-token context window (both default and maximum — there's no smaller-context variant), up to 128K output tokens, adaptive thinking, and the same tools and platform features as Claude Sonnet 4.6, with one exception — it does not support Priority Tier. On apimodels.app it's just $1 input / $4.5 output per 1M tokens, balancing capability with a low price.
Yes — Sonnet 5 supports native tool use (function calling) through the Anthropic Messages API (/v1/messages), the format Claude Code and the Anthropic SDK use. Point ANTHROPIC_BASE_URL at https://apimodels.app/api/v1, set the model to claude-sonnet-5, and use your apimodels API key (see /docs/claude-code). Anthropic-API-compatible clients like Cursor work too when configured as a custom Anthropic model. Send tools in Anthropic format ({name, input_schema}); request params are identical to Claude Opus 4.8.
Input $1 / output $4.5 per 1M tokens. Prompt caching is supported: cache-read (hit) tokens are billed at just $0.1/M — a tenth of the input rate — and cache writes at $2/M. The 1M-token context plus caching makes it ideal for long documents, long sessions, and agentic coding.
Sonnet 5 is the newest Sonnet — 1M context + adaptive thinking at $1/$4.5, the best value for most coding/chat/long-document work. Sonnet 4.6 is the previous Sonnet; Opus 4.8 ($3/$13) is for the hardest long-horizon agentic reasoning. Pick claude-sonnet-5 for the newest, cheapest, still-strong option — all share one API key so you can switch by task.
On API Models, Claude Sonnet 5 runs alongside 60+ models on one API key and one balance, so choosing is about fit, not lock-in. It supports 1M Context, Adaptive Thinking, 128K Output, Tool Calling, and you can weigh it on price and capability against other Large Language Model models, then switch by changing a single model-name string — no new account or integration. Browse every Large Language Model option with live pricing at apimodels.app/models.
Claude Sonnet 5 supports: 1M Context, Adaptive Thinking, 128K Output, Tool Calling. See the API Models docs for full parameters and call examples.
Yes. API Models exposes Claude Sonnet 5 through a single unified API and one key — no separate provider accounts, and no need to handle each provider's regional network access yourself.
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