It is not possible to merge existing PDFs together with PDFreactor without generating a PDF from an HTML source document. However, there is a workaround for that. You can convert an empty HTML document to PDF and then merge existing PDFs with it. This can be done using the following code:


Java

PDFreactor pr = new PDFreactor();
Configuration conf = new Configuration();

// An "empty" HTML document
conf.setDocument("<html>");

// Make the document really small so that the PDFs can overlay it
conf.setUserStyleSheets(new Resource().setContent("@page { size: 1in 1in; }"));

conf.setMergeSettings(new MergeSettings()
    // Set merge mode to "Overlay" to overlay the "empty" page over the existing PDFs
    .setMode(MergeMode.OVERLAY)

    // Merge the existing PDFs
    .setMergeDocuments(
        new Resource().setUri("url/to/documentA.pdf"),
        new Resource().setUri("url/to/documentB.pdf"),
        new Resource().setUri("url/to/documentC.pdf")
    )
);

pr.convertAsBinary(conf);

C#

PDFreactor pr = new PDFreactor();
Configuration conf = new Configuration();

// An "empty" HTML document
conf.Document = "<html>";

// Make the document really small so that the PDFs can overlay it
conf.UserStyleSheets = new List<Resource>
{
    new Resource { Content = "@page { size: 1in 1in; }" }
};

conf.MergeSettings = new MergeSettings {
    // Set merge mode to "Overlay" to overlay the "empty" page over the existing PDFs
    Mode = MergeMode.OVERLAY;

    // Merge the existing PDFs
    MergeDocuments = new List<Resource>
    {
        new Resource { Uri = "url/to/documentA.pdf" },
        new Resource { Uri = "url/to/documentB.pdf" },
        new Resource { Uri = "url/to/documentC.pdf" }
    }
};

pr.ConvertAsBinary(conf);

PHP

$pr = new PDFreactor();
$conf = [];

// An "empty" HTML document
$conf["document"] = "<html>";

// Make the document really small so that the PDFs can overlay it
$conf["userStyleSheets"] = [
    [ "content" => "@page { size: 1in 1in; }" ]
];

$conf["mergeSettings"] = [
    // Set merge mode to "Overlay" to overlay the "empty" page over the existing PDFs
    "mode" => MergeMode::OVERLAY,

    // Merge the existing PDFs
    "mergeDocuments" => [
        [ "uri" => "url/to/documentA.pdf" ],
        [ "uri" => "url/to/documentB.pdf" ],
        [ "uri" => "url/to/documentC.pdf" ]
    ]
];

$pr->convertAsBinary($conf);

JavaScript/Node.js

pr = new PDFreactor();
conf = {};

// An "empty" HTML document
conf.document = "<html>";

// Make the document really small so that the PDFs can overlay it
conf.userStyleSheets = [
    { content: "@page { size: 1in 1in; }" }
];

conf.mergeSettings = {
    // Set merge mode to "Overlay" to overlay the "empty" page over the existing PDFs
    mode: PDFreactor.MergeMode.OVERLAY,

    // Merge the existing PDFs
    mergeDocuments: [
        { uri: "url/to/documentA.pdf" },
        { uri: "url/to/documentB.pdf" },
        { uri: "url/to/documentC.pdf" }
    ]
};

pr.convertAsBinary(conf);

Python

pr = PDFreactor()
conf = {}

# An "empty" HTML document
conf["document"] = "<html>"

# Make the document really small so that the PDFs can overlay it
conf["userStyleSheets"] = [
    { "content": "@page { size: 1in 1in; }" }
]

conf["mergeSettings"] = {
    # Set merge mode to "Overlay" to overlay the "empty" page over the existing PDFs
    "mode": PDFreactor.MergeMode.OVERLAY,

    # Merge the existing PDFs
    "mergeDocuments": [
        { "uri": "url/to/documentA.pdf" },
        { "uri": "url/to/documentB.pdf" },
        { "uri": "url/to/documentC.pdf" }
    ]
}

pr.convertAsBinary(conf)

Ruby

pr = PDFreactor.new()
conf = {}

# An "empty" HTML document
conf["document"] = "<html>"

# Make the document really small so that the PDFs can overlay it
conf["userStyleSheets"] = [
    { content: "@page { size: 1in 1in; }" }
]

conf["mergeSettings"] = {
    # Set merge mode to "Overlay" to overlay the "empty" page over the existing PDFs
    "mode": PDFreactor::MergeMode::OVERLAY,

    # Merge the existing PDFs
    "mergeDocuments": [
        { uri: "url/to/documentA.pdf" },
        { uri: "url/to/documentB.pdf" },
        { uri: "url/to/documentC.pdf" }
    ]
}

pr.convertAsBinary(conf)

REST

{ "document": "<html>", "userStyleSheets": [{ "content": "@page { size: 1in 1in; }" }], "mergeSettings": { "mode": "OVERLAY", "mergeDocuments": [{ "uri": "url/to/documentA.pdf" }, { "uri": "url/to/documentB.pdf" }, { "uri": "url/to/documentC.pdf" }]} }