HTML to PDF API: CustomJS vs Alternatives

What Is an HTML-to-PDF API?

An HTML to PDF API is a service that converts web content, such as raw HTML, URLs, or templates, into a downloadable PDF file. It supports styling with inline CSS, CSS selectors, and responsive designs, allowing precise formatting for headers, footers, and page margins in millimeters.

Unlike a simple browser print function, an API offers PDF conversion options such as portrait orientation, metadata relevant fields, and footer HTMLString, making it ideal for automation inside workflows.

Typical use cases go beyond basic downloads. PDFs are nearly universal in businesses. 98% of companies use PDFs as their default format for external communication. It is no wonder: APIs are essential for generating reliable documents at scale. Use cases range from invoices with dynamic data to contracts, reports, and even archiving a website to PDF, all part of modern PDF automation.

How CustomJS Converts HTML to PDF

CustomJS makes HTML to PDF conversion straightforward while keeping it flexible for different workflows. Users send raw HTML, a URL, or a Nunjucks template. You could write you a CustomJS function to call it via an API, or you could use our native PDF generation modules in Make.com or n8n.

const { HTML2PDF } = require('./utils'); 

return HTML2PDF(input.html);

This setup makes PDF automation practical for invoices, certificates, and reports inside Make.com workflows without extra coding effort.

CustomJS vs. Top 5 HTML-to-PDF APIs

1. CustomJS vs. HTML2PDF

HTML2PDF offers a quick way to turn a website to PDF, but it comes with clear trade-offs. The service does not support JavaScript execution, so features like inline CSS, CSS selector targeting, or dynamic values cannot be applied during HTML to PDF conversion. Pricing is another drawback at scale. It charges nearly seven times more per 1,000 PDFs compared to CustomJS, making bulk PDF automation expensive.

Pricing

HTML2PDF is free to use, whereas CustomJS offers 600 free requests per month along with paid plans.

Features

• JavaScript templating with Nunjucks
• Multiple rendering engines (Chromium, wkhtmltopdf, Puppeteer)
• Control over margin in millimeters, portrait orientation, footer HTMLString, and metadata relevant fields

When HTML2PDF.com wins

HTML2PDF is useful for one-off conversions where simplicity matters more than flexibility. If all that’s needed is to take a static webpage and save it as a PDF file without custom styling or element selector string targeting, it provides a straightforward option.

2. CustomJS vs. PDF.co

PDF.co includes extras such as OCR, barcode generation, and data extraction, which can be useful in very specific workflows. However, its higher cost per request and usage caps make it less attractive for teams that only need HTML to PDF conversion.

For standard use cases, such as invoices or reports, the extra features often go unused while the bill continues to grow. In speed benchmarks, CustomJS generates a PDF file 2–3 times faster, which is important when running bulk PDF automation.

Pricing

PDF.co’s pricing plans are as follows:

• Basic: $9.99/mo
• Personal: $24.99/mo
• Business1: $49.99/mo
• Business 2: $99.99/mo
• Business 3: $299.99/mo
• Enterprise: custom plan

Features

• Full JavaScript support with inline CSS and element selector string control
• Multiple rendering engines (Chromium, wkhtmltopdf, Puppeteer)
• Options for portrait orientation, metadata relevant settings, and margin in millimeters
• Make.com and n8n integration for auto-generated code snippet workflows

When PDF.co wins

It is a better fit when OCR or barcode utilities are a strict requirement. For example, scanning receipts and embedding barcode values into a contract PDF is an edge case where PDF.co’s bundled toolkit stands out. For pure HTML to PDF API usage, CustomJS remains faster and more cost-effective.

3. CustomJS vs. ConvertAPI

ConvertAPI supports a wide range of file types, making it flexible for document transformations beyond html to pdf conversion. The drawback is its billing model, charges are based on megabytes transferred rather than the number of PDFs. For standard-size invoices, contracts, or reports, this can cause unpredictable costs, especially when designs include images or charts. CustomJS, with flat per-request pricing, makes budgeting easier for businesses that rely on repeat PDF automation.

Pricing

ConvertAPI’s pricing plans range from $35 to $350 per month. CustomJS has predictable pricing at scale.

Features

• JavaScript support with inline CSS and CSS selector control
• Choice of Chromium, wkhtmltopdf, or Puppeteer engines
• Portrait orientation, margin in millimeters, and footer HTMLString
• Split and merge along with PDF accessibility
• Redact and Extract PDFs

When ConvertAPI wins

ConvertAPI is best for teams that need occasional multi-format conversions, such as turning Word, Excel, or images into a PDF file. For businesses focused primarily on HTML to PDF API workloads, CustomJS offers simpler, cheaper, and more consistent performance.

4. CustomJS vs. DocRaptor

DocRaptor is designed for enterprises and supports detailed CSS handling for HTML to PDF conversion. It removes branding, offers enterprise hosting, and is known for accurate layouts. However, its pricing is steep, around $15 per 1,000 PDFs, compared to CustomJS’s ~$0.15 per 1,000 with a 600-per-month free plan.

Pricing

As compared to DocRaptor, CustomJS is significantly cheaper at scale.

Features

• Accepts HTML, URLs, and Nunjucks templates
• Engines available: Chromium, wkhtmltopdf, Puppeteer
• JavaScript support for inline data (prices, dates, IDs)
• Control over orientation, margins, and footer HTMLString

When DocRaptor wins

A better choice if an organization requires strict enterprise compliance, branding removal, or SVG-heavy rendering for design-focused reports. For most invoice, report, and contract workloads, CustomJS achieves the same PDF generation api results at a fraction of the price.

5. CustomJS vs. Api2Pdf

Api2PDF is a popular HTML to PDF API that supports Chromium and wkhtmltopdf engines. It works well for basic conversions, but free usage comes with watermarks, and costs rise quickly at scale. CustomJS removes those barriers by offering 600 free PDFs each month with no watermark, with predictable flat pricing.

Pricing

CustomJS is cheaper per 1,000 PDFs and includes a watermark-free free plan.

Features

• CustomJS: `/pdf/generate` endpoint, HTML/URL/Nunjucks input
• Engines: Chromium, wkhtmltopdf, Puppeteer
• JavaScript execution for dynamic values
• Orientation, margin in millimeters, footer HTMLString, metadata relevant settings

When Api2Pdf wins

API2Pdf is a better choice for developers who only need a quick API with Chromium rendering. It can also work for small projects where watermarking is not a concern or where a third-party-hosted service is preferred.

6. CustomJS vs. PDFShift

PDFShift is for developers who want speed and bulk processing. It supports batch jobs and high concurrency, making it attractive when thousands of documents must be processed in parallel. However, its pricing increases quickly as volume grows, and it lacks built-in workflow modules. CustomJS, by contrast, keeps flat per-request pricing and supports JavaScript execution for dynamic HTML to PDF conversion.

Pricing

PDFShift has a free trial with 50 credits, then starts at $9/mo for 100 documents.

Features

PDFShift specializes in batch processing and high concurrency, but doesn’t include native integrations with Make.com or n8n.

When PDFShift wins

PDFShift is best suited for teams that need bulk, parallel HTML to PDF conversion jobs and can manage workflows entirely via API.

7. CustomJS vs. PDFCrowd

PDFCrowd is an HTML to PDF API focused on simplicity. It works well with basic HTML input but does not support JavaScript execution, so dynamic values and interactive layouts cannot be rendered. Its feature set is limited compared to CustomJS, which supports inline CSS, CSS selector control, and JavaScript templating, which makes it more suitable for invoices, reports, and automated PDF generation api workflows.

Pricing

PDFCrowd’s pricing ranges from $1/mo for 10 credits to $2630/mo for 3.000.000 credits.

Features

PDFCrowd works well for static HTML input but lacks JavaScript, advanced styling, and workflow modules.

When PDFCrowd wins

PDFCrowd fits use cases where only static HTML needs to be turned into a PDF file, such as simple reports or plain contracts, without dynamic data or responsive designs.

When an Alternative Might Fit Better?

Some situations call for alternatives to CustomJS. If a company requires a signed HIPAA Business Associate Agreement (BAA) for healthcare compliance or insists on EU-only hosting, services like DocRaptor may be more appropriate.

Organizations that need to process 10 million+ PDFs per month might also benefit from running their own wkhtmltopdf setup on-premises, where complete control over infrastructure is essential.

For the vast majority of cases, such as generating invoices, long-form reports, certificates, or automated screenshots, CustomJS delivers the same HTML to PDF conversion results at predictable pricing and with flexible JavaScript support, making it the practical choice for most businesses.

Frequently Asked Questions

1. What makes an HTML to PDF API different from a browser “Print to PDF”?

A browser “Print to PDF” works manually and is limited to what’s on screen. An HTML to PDF API runs automatically inside workflows, accepts raw HTML or URLs, applies inline CSS, margins in millimeters, and a footer HTML string, and returns a PDF file programmatically. This makes it reliable for PDF automation at scale.

2. Does CustomJS support dynamic JavaScript and CSS in PDFs?

Yes. CustomJS executes JavaScript within the conversion process, so invoices can include live prices, dates, or IDs. It also applies CSS selectors, inline CSS, and responsive designs, ensuring layouts render accurately during HTML to PDF conversion.

3. How many free PDFs can I generate each month?

CustomJS offers a free plan of 600 PDFs per month (20 per day). Each request counts as one PDF generation API call, whether you’re converting an invoice, a report, or a certificate from HTML.

4. Can I merge multiple PDFs after generation?

Yes. With CustomJS’s built-in PDF utils, you can merge multiple files, extract pages, or compress them after HTML to PDF conversion. This is useful for combining invoices, contracts, or batch-generated reports into a single PDF file.

5. Which API is the fastest under 2 MB HTML payloads?

Benchmarks show that CustomJS renders a 2 MB HTML payload 2–3 times faster than alternatives like PDF.co or DocRaptor. Using Chromium or Puppeteer engines, it returns a finished PDF file in seconds, making it highly efficient for bulk PDF automation.

6. Is there a Make.com template I can clone today?

Yes. CustomJS provides a ready-to-use Make.com module for HTML to PDF API workflows. Users can drop in the “Generate PDF” step, paste their API key, and map fields such as HTML input, orientation, and margin in millimeters. The result is an auto-generated code snippet ready for invoices or reports.

Key Takeaways

When it comes to HTML to PDF conversion, the real choice is between paying more for niche features or using a service built for everyday document needs.

CustomJS keeps it simple: a flat per-request model, 600 free PDFs each month, and support for JavaScript, inline CSS, and precise layout controls like margins in millimeters or footer HTMLString.

CustomJS also fits neatly into existing workflows. You can plug it into Make.com scenarios in minutes, use it for automated PDF generation, or migrate from Zapier with the step-by-step migration guide.

Try it today!