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Claude

Claude Sonnet 5: Online Chat & API

claude-sonnet-5

Anthropic's balanced flagship — near-Opus intelligence at a fraction of the cost. Chat with it right here in your browser, or wire it into your app through one OpenAI-compatible endpoint.

Input 510 ₽ · Output 2 550 ₽ /1M tokens1M context Thinking Prompt caching
API key
claude-sonnet-5
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Try it right here

Real model, streaming live — free trial credits on sign-up

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About Claude Sonnet 5

Claude Sonnet 5 is Anthropic's most capable Sonnet-class model, built for frontier-level performance across coding, agent workflows and professional knowledge work. It pairs strong reasoning with fast, cost-efficient inference, making it the default choice when you need top-tier quality without Opus-level spend.

The model ships with a 1M-token context window and adaptive thinking: instead of a fixed reasoning budget, it decides on its own how much deliberation a request deserves — quick answers stay instant, hard problems automatically get deeper reasoning. Combined with prompt caching that discounts repeated context by up to 90%, it is particularly economical for agents, RAG pipelines and coding assistants that resend large stable prompts.

On Sozdai you can use Claude Sonnet 5 two ways with one account and one credit balance: chat in the browser playground on this page, or call it programmatically through an OpenAI-compatible endpoint (an Anthropic-native /v1/messages endpoint is available too). Pricing is pure pay-as-you-go per token with no subscription.

Why Claude Sonnet 5

Frontier-level reasoning

Top-tier performance on coding, analysis and long-form writing, with a 1M-token context window that holds entire codebases or document sets in one conversation.

Adaptive thinking

The model decides when to think deeper. Hard problems get extra reasoning automatically — no parameters to tune, matching the official API behavior.

Prompt caching, up to 90% off

Repeated context (system prompts, tools, documents) is cached and billed at a tenth of the input price. Ideal for agents and RAG workloads.

OpenAI-compatible API

Point your existing OpenAI SDK at our base URL and it just works — streaming, tool calling, usage accounting included. Anthropic-native /v1/messages is supported too.

Works with your tools

Claude Code, Cursor, Cline and any OpenAI-style client connect in minutes with our step-by-step guides.

One balance for everything

Web chat and API share the same credit balance and transparent per-token pricing. No subscription, no minimums.

Specifications

Model IDclaude-sonnet-5
FamilyClaude
TypeLLM
Context window1M tokens
Input price510 ₽ / 1M tokens
Output price2 550 ₽ / 1M tokens
Cache read price51 ₽ / 1M tokens
Thinking / reasoningYes
Prompt cachingYes
API compatibilityOpenAI SDK + Anthropic /v1/messages
StreamingYes

Integrate in three steps

1

Create an API key

Sign up, open the console and issue a key — free trial credits are included, no card required.

2

Point your SDK at Sozdai

Set the base URL to our endpoint and pass model "claude-sonnet-5". Existing OpenAI SDK code needs no other changes.

3

Ship and monitor

Stream responses in production and track every request's tokens and cost in the usage logs.

Frequently asked questions

Can I try Claude Sonnet 5 without writing code?+

Yes — the playground on this page is the real model. Sign up, get trial credits and chat instantly; the same account later works for the API.

Is the API compatible with the OpenAI SDK?+

Yes. Use any OpenAI SDK (Python, Node, etc.) with our base URL, or call the Anthropic-native /v1/messages endpoint — both are supported with streaming.

How does pricing work?+

Pure pay-as-you-go per token, shown on this page and billed from your credit balance (1 credit = $0.01). Prompt cache hits are billed at a heavily discounted rate. No subscription.

Does it support thinking / reasoning mode?+

Yes. Claude Sonnet 5 uses adaptive thinking — it automatically decides how much to reason based on the difficulty of your request, identical to the official API behavior.

Can I use it in Claude Code, Cursor or Cline?+

Yes. We publish setup guides for each — configuration is a base URL plus your Sozdai API key.

What is the context window?+

1M tokens — enough for entire codebases, book-length documents and very long multi-turn conversations.