PDF Merge API

BASE URLhttps://api-server.compdf.com/server/

❖ Feature Description

Merge multiple PDF files into a single PDF in order, with per-file page ranges and passwords.

❖ Request Mode

Synchronous Request (Sync) ✓

The API returns the result file directly after processing. Recommended for small files and real-time interactive scenarios that need immediate feedback.

Asynchronous Request (Async)

The API first returns task acceptance information, then you query progress and results with taskId. Suitable for large files and batch workloads.

Secure Request Mode

Upload and process files through secure mechanisms such as pre-signed URLs. Suitable for high-security and privacy compliance scenarios.

▎Call Flow

1Upload file

2Call API (sync)

3Get result URL

4Download file

▎Usage Limits

Download validity

24 hours

Execute synchronously

POSThttps://api-server.compdf.com/server/v2/process/pdf/merge

❖ Request Parameters

x-api-key*

Authentication credential sent in the header: x-api-key

Body Parameters multipart/form-data

fileFile[]*

Choose Files

No file selected

List of PDF files to merge (at least 2). Submission order determines merge order.

passwordstring

Default open password. Use this if all source PDFs share the same password; otherwise use passwords[] for per-file passwords.

languageinteger

API error message language. 1 = English, 2 = Chinese (default).

filePageRangesarray

File 1

File 2

Each row maps 1:1 to a file in the upload list above; fill in one row per file in the same order.

Page ranges corresponding one-to-one with the file[] list; provide one entry for each file. Page numbers start at 1. Use "all" or a format such as "1-3,6", with multiple segments separated by commas.

passwordsarray

File 1

File 2

Each row maps 1:1 to a file in the upload list above; fill in one row per file in the same order.

Open passwords corresponding one-to-one with the file[] list. Use an empty string as a placeholder for files that do not require a password.

outputFileNamestring

Output PDF file name. Defaults to merged.pdf if not provided.

❖ Response Properties

Field	Type	Description
code	String	Business status code
msg	String	Message
data	Array	Response data
data[].fileKey	String	Unique key of the file in the storage system.
data[].taskId	String	Task ID. Returned after task creation; used to launch conversion or query task status.
data[].fileName	String	Source file name. Required in presigned mode to generate the object storage upload URL.
data[].downFileName	String	Output file name after conversion.
data[].fileUrl	String	Source file storage URL or object storage key.
data[].downloadUrl	String	File download URL
data[].sourceType	String	Source file type or feature category, e.g. pdf, docx, img, documentAI, idp.
data[].targetType	String	Target file type or feature, e.g. docx, pdf, split, ocr.
data[].fileSize	Integer	Source file size in bytes.
data[].convertSize	Integer	Converted file size in bytes.
data[].convertTime	Integer	Conversion time for a single file, typically in milliseconds.
data[].status	String	File processing status. Common values: success, failed, processing, etc.
data[].failureCode	String	Error code when file conversion fails.
data[].failureReason	String	Error reason when file conversion fails.
data[].fileParameter	String	Conversion parameter JSON string submitted when creating the task.

🔗Request Example

curl --request POST \
  --url https://api-server.compdf.com/server/v2/process/pdf/merge \
  --header 'x-api-key: YOUR API-KEY' \
  --form [email protected] \
  --form [email protected]

✓Response Example

200 OK

{
  "code": "200",
  "msg": "success",
  "data": [
    {
      "fileKey": "<string>",
      "taskId": "<string>",
      "fileName": "<string>",
      "downFileName": "<string>",
      "fileUrl": "<string>",
      "downloadUrl": "<string>",
      "sourceType": "<string>",
      "targetType": "<string>",
      "fileSize": 0,
      "convertSize": 0,
      "convertTime": 0,
      "status": "<string>",
      "failureCode": "<string>",
      "failureReason": "<string>",
      "fileParameter": "<string>"
    }
  ]
}