How to Merge PDF Files with cURL

Learn how to merge PDF documents using cURL to call the Merge PDFs API Tool from pdfRest.
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Why Use Merge PDFs with cURL?

The pdfRest Merge PDFs API Tool is a powerful resource that allows users to combine multiple PDF files into a single document programmatically. This tutorial will demonstrate how to send an API call to Merge PDFs using cURL, a command-line tool for making HTTP requests. cURL is widely used for its simplicity and versatility in interacting with web APIs, making it an ideal choice for developers looking to automate tasks or integrate PDF processing capabilities into their applications.

Consider a scenario where a business needs to consolidate several reports into one document for a quarterly review. Instead of manually combining these files, which can be time-consuming and prone to errors, the business can use the Merge PDFs API to automate the process. This ensures a consistent and efficient workflow, especially when dealing with a large number of documents or when such tasks need to be performed regularly.

Merge PDFs with cURL Code Example

curl -X POST "" \
  -H "Accept: application/json" \
  -H "Content-Type: multipart/form-data" \
  -H "Api-Key: xxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" \
  -F "file=@/path/to/file" \
  -F "pages[]=all" -F "type[]=file" \
  -F "file=@/path/to/file" \
  -F "pages[]=all" -F "type[]=file" \
  -F "output=example_out"

Reference to the code: pdf-rest-api-samples

Breaking Down the Code

This section will explain the different parts of the cURL command used to call the Merge PDFs API:


This specifies the HTTP method for the request, which is POST in this case, indicating that data will be sent to the server to create or update a resource.

-H "Accept: application/json"

This header tells the server that the client expects a response in JSON format.

-H "Content-Type: multipart/form-data"

This header indicates that the data being sent in the request is in multipart/form-data format, which is used for uploading files.

-H "Api-Key: xxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"

The API key is required for authentication with the pdfRest API. Replace the placeholder with your actual API key.

-F "file=@/path/to/file"
-F "pages[]=all" -F "type[]=file"

Here, -F adds a multipart form field called file with the file to be uploaded. The '@' symbol indicates that the following string is a file path, which you should replace with the actual path to your PDF file. Next, the pages[] form field specifies the pages of the uploaded file to be included. Finally, the type[] field indicates that this resource is a file.

Each of these three fields must be included for each file that will be merged.

-F "output=example_out"

This form field sets the name of the output file that will be generated after merging the PDFs.

Beyond the Tutorial

By following the steps above, you've learned how to merge PDF files using the pdfRest Merge PDFs API with a cURL command. This is just one of the many capabilities offered by pdfRest. To explore and demo all of the pdfRest API Tools, visit the API Lab. For more detailed information and additional endpoints, refer to the API Reference Guide.

Note: This is an example of a multipart API call. For code samples using JSON payloads, visit pdf-rest-api-samples with JSON payloads.

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