The PDF merge REST API — combine uploads and URLs into one PDF.

using System;
using SelectPdf.Api;

PdfMergeClient client = new PdfMergeClient(apiKey);

// Add files in the order they appear in the merged PDF
client.addUrlFile(testUrl);                  // remote URL
client.addFile(testPdf);                     // local upload
// client.addFile(testPdf, "src_password"); // with password

// Optional: protect + label the merged output
client.setUserPassword("secret");
client.setDocTitle("Combined statement");

// --- Merge to a local file ---
client.saveToFile(localFile);
Console.WriteLine("Pages: " + client.getNumberOfPages());
Console.WriteLine("Credits left: " + client.CreditsRemaining);

package com.selectpdf;

PdfMergeClient client = new PdfMergeClient(apiKey);

// Add files in the order they appear in the merged PDF
client.addUrlFile(testUrl);                  // remote URL
client.addFile(testPdf);                     // local upload
// client.addFile(testPdf, "src_password"); // with password

// Optional: protect + label the merged output
client.setUserPassword("secret");
client.setDocTitle("Combined statement");

// --- Merge to a local file ---
client.saveToFile(localFile);
System.out.printf("Pages: %d%n", client.getNumberOfPages());

UsageClient u = new UsageClient(apiKey);
System.out.println("Usage: " + u.getUsage(false));

require("SelectPdf.Api.php");

$client = new SelectPdf\Api\PdfMergeClient($apiKey);

// Add files in the order they appear in the merged PDF
$client->addUrlFile($testUrl);                 // remote URL
$client->addFile($testPdf);                    // local upload
// $client->addFile($testPdf, "src_password"); // with password

// Optional: protect + label the merged output
$client->setUserPassword("secret");
$client->setDocTitle("Combined statement");

// --- Merge to a local file ---
$client->saveToFile($localFile);
echo "Pages: " . $client->getNumberOfPages() . "\n";

$u = new \SelectPdf\Api\UsageClient($apiKey);
$usage = $u->getUsage(false);
echo "Credits: " . $usage["available"] . "\n";

import selectpdf

client = selectpdf.PdfMergeClient(apiKey)

# Add files in the order they appear in the merged PDF
client.addUrlFile(testUrl)                 # remote URL
client.addFile(testPdf)                    # local upload
# client.addFileWithPassword(testPdf, "src_password")  # with password

# Optional: protect + label the merged output
client.setUserPassword("secret")
client.setDocTitle("Combined statement")

# --- Merge to a local file ---
client.saveToFile(localFile)
print("Pages:", client.getNumberOfPages())

usage = selectpdf.UsageClient(apiKey).getUsage()
print("Credits:", usage["available"])

var selectpdf = require('selectpdf');

var client = new selectpdf.PdfMergeClient(apiKey);

// Add files in the order they appear in the merged PDF
client.addUrlFile(testUrl);                  // remote URL
client.addFile(testPdf);                     // local upload
// client.addFile(testPdf, 'src_password');  // with password

// Optional: protect + label the merged output
client.setUserPassword('secret');
client.setDocTitle('Combined statement');

// --- Merge to a local file ---
client.saveToFile(localFile, function(err, file) {
    if (err) return console.error('Merge error:', err);
    console.log('Pages:', client.getNumberOfPages());
});

require 'selectpdf'

client = SelectPdf::PdfMergeClient.new(api_key)

# Add files in the order they appear in the merged PDF
client.add_url_file(test_url)              # remote URL
client.add_file(test_pdf)                  # local upload
# client.add_file(test_pdf, 'src_password')  # with password

# Optional: protect + label the merged output
client.user_password = 'secret'
client.doc_title = 'Combined statement'

# --- Merge to a local file ---
client.save_to_file(local_file)
print "Pages: #{client.number_of_pages}\n"

usage = SelectPdf::UsageClient.new(api_key).get_usage(false)
print "Credits: #{usage['available']}\n"

use SelectPdf;
use JSON;

my $client = SelectPdf::PdfMergeClient->new($apiKey);

# Add files in the order they appear in the merged PDF
$client->addUrlFile($test_url);              # remote URL
$client->addFile($test_pdf);                 # local upload
# $client->addFileWithPassword($test_pdf, "src_password");

# Optional: protect + label the merged output
$client->setUserPassword("secret");
$client->setDocTitle("Combined statement");

# --- Merge to a local file ---
$client->saveToFile($local_file);
print "Pages: " . $client->getNumberOfPages() . "\n";

my $u = SelectPdf::UsageClient->new($apiKey);
print "Credits: " . $u->getUsage(0)->{"available"} . "\n";

// No dedicated Go SDK — POST /api2/pdfmerge/ over net/http.
package main

import (
    "bytes"
    "io"
    "mime/multipart"
    "net/http"
    "os"
)

const apiURL = "https://selectpdf.com/api2/pdfmerge/"

func main() {
    b := &bytes.Buffer{}
    w := multipart.NewWriter(b)
    w.WriteField("key", apiKey)
    w.WriteField("files_no", "2")
    w.WriteField("url_1", testUrl)       // file 1: remote URL
    // file 2: upload as multipart part named "file_2"
    f, _ := os.Open(testPdf)
    defer f.Close()
    part, _ := w.CreateFormFile("file_2", testPdf)
    io.Copy(part, f)
    w.Close()

    req, _ := http.NewRequest("POST", apiURL, b)
    req.Header.Set("Content-Type", w.FormDataContentType())
    resp, _ := http.DefaultClient.Do(req)
    defer resp.Body.Close()

    out, _ := os.Create(localFile)
    defer out.Close()
    io.Copy(out, resp.Body)
}