128k OpenAI Context Window
Process massive documents with OpenAI GPT 5 mini. The 128,000 token window allows for deep RAG applications and long-form content analysis without losing track of details.

image
text
Image To Text (Response)
curl --request POST "https://gptproto.com/v1/responses" \
--header "Authorization: Bearer $GPTPROTO_API_KEY" \
--header "Content-Type: application/json" \
--data '{
"model": "gpt-5-mini",
"input": [
{
"role": "user",
"content": [
{
"type": "input_text",
"text": "What is in this image?"
},
{
"type": "input_image",
"image_url": "https://tos.gptproto.com/resource/cat.png"
}
]
}
]
}'Image To Text (Chat)
curl --request POST "https://gptproto.com/v1/chat/completions" \
--header "Authorization: Bearer $GPTPROTO_API_KEY" \
--header "Content-Type: application/json" \
--data '{
"model": "gpt-5-mini",
"messages": [
{
"role": "user",
"content": [
{
"type": "text",
"text": "What is in this image?"
},
{
"type": "image_url",
"image_url": {
"url": "https://tos.gptproto.com/resource/cat.png"
}
}
]
}
],
"max_tokens": 300
}'Discover the technical strengths that make OpenAI GPT 5 mini a leader in cost-efficient AI.
Process massive documents with OpenAI GPT 5 mini. The 128,000 token window allows for deep RAG applications and long-form content analysis without losing track of details.

Achieve 100% reliability in structured outputs. OpenAI GPT 5 mini uses constrained decoding to match your schemas perfectly, which is essential for automated data pipelines.

Reduce overhead with $0.15 per million tokens. OpenAI GPT 5 mini provides frontier-level intelligence at a fraction of the cost of larger models, maximizing your ROI.

Experience Time To First Token under 200ms. OpenAI GPT 5 mini is built for real-time chat and interactive apps where every millisecond counts for the user experience.

Getting a gpt 5 mini API key takes four steps and a few minutes. Create a free GPTProto account, add credits, generate your key, and make your first call — at $0.175 / $1.4 it's a cheaper gpt 5 mini API key than going direct, and one key works across every model on the platform. Full gpt 5 mini Documentation is in the docs.

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