GPT-5.6 · GPT-5.5 · GPT-5.4 · GPT Image

GPT API

Call the latest GPT models through one OpenAI-compatible API key. Use GPT-5.6 Sol, Luna, and Terra, GPT-5.5, GPT-5.4, GPT-5 mini, GPT-4o, and GPT Image 2 from the same Flatkey account.

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

GPT API access

ModeloFlatkeyReference
GPT-5.5 output / 1M tokens$10.00$15.00
GPT-5.4 and GPT-5 miniOne keySeparate setup
GPT-4o and GPT Image 2One keySeparate setup

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

Latest GPT model coverage

Use GPT-5.6 Sol, Luna, and Terra, GPT-5.5, GPT-5.4, GPT-5 mini, GPT-4o, GPT-4.1 mini, and GPT Image 2 from one catalog as they are available.

OpenAI-compatible API

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

Text and image workloads

Route chat, coding, automation, content, and image generation through one account with pricing visibility before you scale.

One account for model comparison

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

GPT API

Call the latest GPT models through one OpenAI-compatible API key. Use GPT-5.6 Sol, Luna, and Terra, GPT-5.5, GPT-5.4, GPT-5 mini, GPT-4o, and GPT Image 2 from the same Flatkey account.

Get your GPT API key

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

Which GPT models can I use?

Current catalog coverage includes GPT-5.6 Sol, GPT-5.6 Luna, GPT-5.6 Terra, GPT-5.5, GPT-5.4, GPT-5.4 mini, GPT-5.4 nano, GPT-5 mini, GPT-4o, GPT-4o mini, GPT-4.1 mini, and GPT Image 2 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 GPT model id you need, such as gpt-5.5.

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.