OpenAI Multimodal Responses

OpenAI-compatible Responses API. This endpoint uses OpenAI-style input, supports text, public image URLs, PDF file input, tool calls, reasoning options, and streaming parameters.

POST https://api.requestbeam.com/openai/responses

Authentication

All requests require Bearer Token authentication.

Authorization: Bearer YOUR_API_KEY

Body

Model Parameter Differences

• Native OpenAI-compatible Responses forwarding preserves top_p in the upstream request; validation and sampling behavior depend on the selected model and upstream. The checks on 2026-09-26 accepted top_p: 0.9 for gpt-5.5, gpt-5.6-sol, and gpt-5.6-terra. Acceptance and forwarding do not prove a sampling effect or guarantee support for other values, models, or later requests. Start with a minimal request.
• Support on this page applies only to the regular /openai/responses endpoint. It does not imply that the same model supports /openai/responses/compact, WebSocket, or stateful previous_response_id.
• The five GPT models listed above currently have no verified Compact channel. Compact requests are rejected before billing when no explicitly enabled channel is available. Ordinary Responses and Responses WebSocket remain available.

Request Examples

The examples below provide input. A continuation may omit input when it provides a valid previous_response_id and the selected channel supports stateful continuation. A response ID does not enable that capability on an unsupported channel. Tool results remain valid input items, including function_call_output.

Text

{
  "model": "gpt-5.4",
  "input": "Hello, introduce yourself in one sentence."
}

Codex CLI-Style Parameters

{
  "model": "gpt-5.5",
  "input": "Reply with READY only.",
  "reasoning": {
    "effort": "xhigh"
  },
  "store": false,
  "text": {
    "verbosity": "low"
  },
  "stream": true
}

Image Understanding

{
  "model": "gpt-5.4",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "What is in this image?"
        },
        {
          "type": "input_image",
          "image_url": "https://example.com/cat.png",
          "detail": "high"
        }
      ]
    }
  ]
}

File Input

Use file_data plus filename to submit PDF content. file_data must be a complete Data URL.

{
  "model": "gpt-5.4",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "Summarize the key points in this PDF."
        },
        {
          "type": "input_file",
          "file_data": "data:application/pdf;base64,JVBERi0xLjQKJc...",
          "filename": "report.pdf"
        }
      ]
    }
  ]
}

Image and File Input

{
  "model": "gpt-5.4",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "Give three conclusions based on the image and attachment."
        },
        {
          "type": "input_image",
          "image_url": "https://example.com/chart.png",
          "detail": "high"
        },
        {
          "type": "input_file",
          "file_data": "data:application/pdf;base64,JVBERi0xLjQKJc...",
          "filename": "notes.pdf"
        }
      ]
    }
  ]
}

Streaming Output

{
  "model": "gpt-5.4",
  "stream": true,
  "input": [
    {
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "Explain this diagram step by step."
        },
        {
          "type": "input_image",
          "image_url": "https://example.com/diagram.png"
        }
      ]
    }
  ]
}

Response

Non-streaming responses follow OpenAI Responses style. Actual fields may vary with selected model capabilities.

Success Example

{
  "id": "resp_123",
  "object": "response",
  "created_at": 1766534400,
  "model": "gpt-5.4",
  "output": [
    {
      "type": "message",
      "role": "assistant",
      "content": [
        {
          "text": "The image shows a cat, and the attachment is a document about pet care."
        }
      ]
    }
  ],
  "usage": {
    "input_tokens": 128,
    "output_tokens": 42,
    "total_tokens": 170
  }
}

Streaming Response

When stream=true, the endpoint returns Server-Sent Events.

event: response.output_text.delta
data: {"type":"response.output_text.delta","delta":"The image"}

event: response.completed
data: {"type":"response.completed","response":{"id":"resp_123"}}

Read events until response.completed or the connection closes.

Error Response

See Error Codes and Troubleshooting for the full code reference, protocol differences, and diagnostic steps.

Platform-generated HTTP errors use the flat fields below instead of an error wrapper. Some upstream errors may retain their original structure; errors inside an already-started SSE stream do not follow this HTTP response example.

{
  "code": 40000,
  "message": "Insufficient credit. Required: 30000, Available: 20000",
  "type": "api_error"
}

Notes

• The Responses endpoint uses input, not messages. If your client only sends messages, use /openai/v1/chat/completions.
• Image input uses input_image; image_url must be a public http:// or https:// URL. Base64 Data URLs are not supported for images.
• File input uses input_file. For PDFs, use file_data plus filename; file_data should be a complete data:application/pdf;base64,... URL.
• Audio input/output, image generation tools, file search, and other advanced capabilities depend on the selected model and available features.
• The fields listed on this page form the current public Responses request contract; do not assume unlisted fields are available.
• /openai/responses is the recommended public path.
• /v1/responses follows the same public request and response contract.
• /compat/v1/responses follows the same public request and response contract.
• /openai/v1/responses follows the same public request and response contract.