Merge multiple PDF files with CustomJS API

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Important notice

This workflow is provided as-is. Please review and test before using in production.

1. Workflow Overview

This n8n template demonstrates how to download multiple PDF files from public URLs and merge them into a single PDF using the PDF Toolkit from www.customjs.space. [@cus...

Best for

File Management automation workflows
intermediate n8n builders looking for reusable templates

Tools used

n8n-nodes-base.manualtrigger, n8n-nodes-base.httprequest, n8n-nodes-base.merge, @custom-js/n8n-nodes-pdf-toolkit.mergepdfs, n8n-nodes-base.readwritefile

Source and attribution

This workflow is cataloged by N8N Workflows and links back to its original n8n.io source page by CustomJS.

Original n8n.io source

1.1 Workflow description

Title: Merge multiple PDF files with CustomJS API
Workflow name: Merge multiple PDF files with CustomJS API

This n8n template demonstrates how to download multiple PDF files from public URLs and merge them into a single PDF using the PDF Toolkit from www.customjs.space.

@custom-js/n8n-nodes-pdf-toolkit

Notice

Community nodes can only be installed on self-hosted instances of n8n.

What this workflow does

Downloads each PDF using an HTTP Request.
Populates files into an array with Merge node from n8n.
Merges all downloaded PDFs using the Merge PDF node from the @custom-js/n8n-nodes-pdf-toolkit.
Writes the final merged PDF to disk.

Requirements

Self-hosted n8n instance
CustomJS API key for merging multiple PDF files.
PDF files to be merged to be converted into a PDF

Workflow Steps:

Manual Trigger:
- Runs with user interaction.
HTTP Request Node For PDF Download:
- Pass urls for PDF files to merge.
Merge Node For Array Population:
- Just populates two files into an array.
Merge PDF files:
- Uses the CustomJS node to merge the incoming PDF files into a single PDF file.
- If size of PDF files exceeds 6MB, you can simply pass an array of URLs for PDF files.

Usage

Get API key from customJS

Sign up to customJS platform.
Navigate to your profile page
Press "Show" button to get API key

Set Credentials for CustomJS API on n8n

Copy and paste your API key generated from CustomJS here.

Design workflow

A Manual Trigger for starting workflow.
Two HTTP Request Nodes for downloading PDF files.
A Merge Node for populating files as an array.
Merge PDFs node for merging files
Write to Disk node for saving merged PDF file.

You can replace logic for triggering and returning results. For example, you can trigger this workflow by calling a webhook and get a result as a response from webhook. Simply replace Manual Trigger and Write to Disk nodes.

Perfect for

Bundling reports or invoices.
Generating document sets from external sources.
Automating PDF handling without writing custom code

1.2 Logical Blocks

This catalog entry is organized from the workflow JSON. The node-level section below shows the executable blocks available for review before importing the template.

2. Block-by-Block Analysis

Block 1 - When clicking ‘Test workflow’

Type / Role: n8n-nodes-base.manualTrigger - manualTrigger
Config choices: Version 1

Block 2 - HTTP Request

Type / Role: n8n-nodes-base.httpRequest - httpRequest
Config choices: Version 4.2

Block 3 - HTTP Request2

Type / Role: n8n-nodes-base.httpRequest - httpRequest
Config choices: Version 4.2

Block 4 - Merge

Type / Role: n8n-nodes-base.merge - merge
Config choices: Version 3.1

Block 5 - Merge PDF1

Type / Role: @custom-js/n8n-nodes-pdf-toolkit.mergePdfs - mergePdfs
Config choices: Version 1

Block 6 - Read/Write Files from Disk

Type / Role: n8n-nodes-base.readWriteFile - readWriteFile
Config choices: Version 1

Block 7 - Read/Write Files from Disk4

Type / Role: n8n-nodes-base.readWriteFile - readWriteFile
Config choices: Version 1

3. Summary Table

Workflow	Merge multiple PDF files with CustomJS API
Complexity	intermediate
Nodes	7
Categories	File Management
Author	CustomJS
Published	05 May 2025

4. Reproducing the Workflow from Scratch

1. Download the workflow JSON

Use the JSON export at /data/workflows/3873/3873.json as the source template for this automation.
2. Import the template into n8n

Open n8n, import the downloaded JSON, and review each node before activating the workflow.
3. Configure credentials and variables

Replace placeholder credentials, API keys, webhook URLs, account IDs, and environment-specific values with your own settings.
4. Test with sample data

Run the workflow manually or in a staging workspace, inspect node output, and confirm downstream systems receive the expected data.
5. Activate and monitor

Enable the workflow only after testing, then monitor executions, errors, and rate limits during the first production runs.

5. General Notes & Resources

Review imported nodes carefully before activation. This catalog entry is intended to help you inspect the workflow structure, understand required services, and find related templates faster.

Node names, credentials, schedules, webhook paths, and external service limits may need adjustment for your workspace.

Download workflow JSON Original n8n.io source File Management workflows

Frequently asked questions

What does Merge multiple PDF files with CustomJS API do?

This n8n template demonstrates how to download multiple PDF files from public URLs and merge them into a single PDF using the PDF Toolkit from www.customjs.space. [@cus...

What do I need before importing this workflow?

Review the workflow JSON, configure any required credentials in n8n, and test the automation in a safe workspace before using it in production.

Can I customize this workflow?

Yes. Use the block-by-block analysis and the downloadable JSON to inspect each node, then adjust credentials, prompts, schedules, filters, or destinations for your File Management use case.

CustomJS

22 workflows

Nodes

n8n-nodes-base.manualtrigger n8n-nodes-base.httprequest n8n-nodes-base.merge @custom-js/n8n-nodes-pdf-toolkit.mergepdfs n8n-nodes-base.readwritefile

Complexity

intermediate

Published 05 May 2025

Likes 0

View on n8n.io Download Workflow

Install path: /data/workflows/3873/3873.json

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Merge multiple PDF files with CustomJS API

Workflow preview

Important notice

1. Workflow Overview

Best for

Tools used

Source and attribution

1.1 Workflow description

Notice

What this workflow does

Requirements

Workflow Steps:

Usage

Get API key from customJS

Set Credentials for CustomJS API on n8n

Design workflow

Perfect for

1.2 Logical Blocks

2. Block-by-Block Analysis

Block 1 - When clicking ‘Test workflow’

Block 2 - HTTP Request

Block 3 - HTTP Request2

Block 4 - Merge

Block 5 - Merge PDF1

Block 6 - Read/Write Files from Disk

Block 7 - Read/Write Files from Disk4

3. Summary Table

4. Reproducing the Workflow from Scratch

1. Download the workflow JSON

2. Import the template into n8n

3. Configure credentials and variables

4. Test with sample data

5. Activate and monitor

5. General Notes & Resources

Frequently asked questions