Claude Opus · Sonnet · Haiku

Claude API

Call the latest Claude models through one OpenAI-compatible API key. Use Claude Opus 5, Sonnet 5, Opus 4.8, Sonnet 4.6, and Haiku 4.5 without a separate Anthropic setup.

GPT · Gemini · Claude · DeepSeek · Kimi · Seedance — one key, one invoice · no credit card to start

Claude API access

ModeloFlatkeyReference
Claude Sonnet 5 output / 1M tokens$9.00$10.00
Claude Opus 5 and Opus 4.8One keySeparate setup
Claude Sonnet 4.6 and Haiku 4.5One keySeparate setup

* Representative coverage — see live pricing for current Claude model rates and availability.

Latest Claude model coverage

Use Claude Opus 5, Sonnet 5, Opus 4.8, Sonnet 4.6, Sonnet 4.5, and Haiku 4.5 from the same Flatkey account as they are available in the catalog.

OpenAI-compatible API

Keep the OpenAI SDK already in your application. Change base_url, set a Flatkey API key, and choose the Claude model id you need.

Built for code, agents, and long documents

Claude is a strong fit for coding agents, support automation, analysis workflows, and long-context reasoning where output quality matters.

One account for model comparison

Compare Claude with GPT, Gemini, DeepSeek, Qwen, Kimi, and GLM without creating separate provider accounts or changing your API integration.

Claude API

Call the latest Claude models through one OpenAI-compatible API key. Use Claude Opus 5, Sonnet 5, Opus 4.8, Sonnet 4.6, and Haiku 4.5 without a separate Anthropic setup.

Get your Claude API key

GPT · Gemini · Claude · DeepSeek · Kimi · Seedance — one key, one invoice · no credit card to start

Which Claude models can I use?

Current catalog coverage includes Claude Opus 5, Claude Sonnet 5, Claude Opus 4.8, Claude Opus 4.7, Claude Opus 4.6, Claude Opus 4.5, Claude Sonnet 4.6, Claude Sonnet 4.5, and Claude Haiku 4.5 when available.

Can I use my existing OpenAI SDK?

Yes. Point the SDK at the Flatkey /v1 base URL, use a Flatkey API key, and choose the Claude model id you need, such as claude-sonnet-5.

Do I have to change my code?

No. flatkey.ai is OpenAI-compatible: keep your existing OpenAI SDK and switch base_url plus api_key. Model ids stay the same.

How is billing handled across models?

One plan covers every model. Usage analytics and a single invoice keep spend bounded before you scale.