Merge API Documentation

Send a PDF with your prompt to have a model summarize, answer questions about, or extract from it. Pass it as base64 or a URL in a document block; Gateway converts it to the served vendor’s format.

curl https://api-gateway.merge.dev/v1/responses \
  -H "Authorization: Bearer $MERGE_GATEWAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "google/gemini-3.6-flash",
    "input": [{
      "type": "message",
      "role": "user",
      "content": [
        {"type": "text", "text": "What are the key findings?"},
        {"type": "document", "source_type": "url", "media_type": "application/pdf", "data": "https://example.com/report.pdf"}
      ]
    }]
  }'

AI SDK file parts need merge-gateway-ai-sdk-provider 0.3.0 or later; earlier versions drop them silently.

Reference

Field	Notes
`source_type`	`base64` (default) or `url`
`media_type`	Required, such as `application/pdf`
`data`	Base64 string, or the URL when `source_type` is `url`

Inline documents are capped at 20 MB decoded per request, all documents combined; URLs don’t count. Over the cap returns 413 payload_too_large, and a route without document input returns 400 unsupported_params. Filter by document input in the model catalog.

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