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POST /v1/merge Merge multiple PDFs into a single document. PDFs are combined in array order. 
Authorization: Bearer forme_sk_...

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Request Body

FieldTypeRequiredDescription
pdfsstring[]YesArray of base64-encoded PDF bytes. Minimum 2, maximum 20.

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Examples

curl -X POST https://api.formepdf.com/v1/merge \
  -H "Authorization: Bearer forme_sk_abc123..." \
  -H "Content-Type: application/json" \
  -d "{
    \"pdfs\": [
      \"$(base64 -w0 invoice.pdf)\",
      \"$(base64 -w0 terms.pdf)\"
    ]
  }" \
  --output combined.pdf

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Response

200 OK with Content-Type: application/pdf — the merged PDF.

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Limits

  • Minimum 2 PDFs per request
  • Maximum 20 PDFs per request
  • PDFs are merged in array order — the first PDF’s pages appear first

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What Is Not Merged

The following PDF features from source documents are not carried over in v1:
  • AcroForms — form fields are not merged (use flatten before merging if you need form data preserved visually)
  • Bookmarks — PDF outline entries are not combined
  • Named destinations — internal cross-references between source documents are not resolved
  • Structure trees — tagged PDF accessibility data is not merged
Page content, fonts, images, and annotations are preserved.