PDF merge API

Send two to twenty PDFs as multipart fields and get one merged PDF back. Pages keep the order of the fields you send.

POST /api/v1/pdf/merge

Try it without a key

curl -X POST https://hexloomlabs.com/api/v1/pdf/merge \
  -F file1=@first.pdf -F file2=@second.pdf \
  -o merged.pdf

The keyless demo is limited to 1 MB per call and a best-effort rate limit.

With a RapidAPI key

curl -X POST https://hexloom-file-api.p.rapidapi.com/pdf/merge \
  -H "X-RapidAPI-Key: YOUR_KEY" \
  -F file1=@first.pdf -F file2=@second.pdf \
  -o merged.pdf

The free plan is 100 calls a month; paid plans and prices are shown on the RapidAPI listing before you subscribe. The free plan allows 1 MB per call for this endpoint; paid plans allow 10 MB.

Request

Content type: multipart/form-data, 2 to 20 file fields; any field names; merge order is the order sent.
Output limited to 500 pages.

Responses

200 with application/pdf body: the merged file.
400 need_two_files: fewer than two PDFs sent.
415 unsupported_pdf_filter: the PDF uses a stream encoding the service does not accept (LZW, ASCII85, ASCIIHex or RunLength). Re-save it from a PDF viewer.
400 too_many_files: more than 20 PDFs sent.
413 too_many_pages: the merged output would pass 500 pages.
413 too_large, 429 rate_limited: see limits.

Errors return JSON: {"ok":false,"error":{"code":"...","message":"..."}}.

What it does not do

It does not repair damaged PDFs, remove passwords or run OCR.

What we keep

File contents are held in memory for the length of the request and are not stored or logged by this service. Cloudflare, which hosts it, keeps its usual request logs (time, path, size, IP and request headers; key and secret headers are masked). See the privacy policy and terms. Questions: support.