API Documentation
Introduction
Integrate OncePDF's powerful PDF processing capabilities directly into your application. Our RESTful API allows you to automate merging, splitting, and converting PDFs with ease.
https://api.oncepdf.com/v1
Authentication
All API requests require an API key passed in the `Authorization` header.
Endpoints
/merge
Merge multiple PDF files into one.
/status/{id}
Check the processing status of a file.
Webhooks
Stay notified about file processing results without polling. Configure a webhook URL in your dashboard to receive real-time updates.
{
"event": "file.processed",
"id": "f_982k1",
"url": "https://oncepdf.com/d/abc123def"
}
Error Codes
We use standard HTTP response codes to indicate the success or failure of an API request.
| Code | Description |
|---|---|
| 400 | Bad Request - Often due to missing parameters. |
| 401 | Unauthorized - Invalid or missing API key. |
| 429 | Too Many Requests - Rate limit exceeded. |
| 500 | Server Error - Something went wrong on our end. |
Empowering Developers with Next-Level PDF Processing
Let's take a moment to look under the hood of what makes our API so special. If you've ever had to deal with legacy PDF libraries, you already know the struggle. They are often incredibly bulky, painfully slow, and notoriously difficult to integrate into modern web applications. Just looking at it, the traditional approach to document manipulation feels completely out of sync with how fast today's development cycles move. We experienced those exact same frustrations firsthand, which is precisely why we decided to build something significantly better.
Our API is designed from the ground up with a singular focus: developer experience. We wanted to create a streamlined, robust system that actually makes sense. By leveraging the immense power of WebAssembly and HTML5, we've managed to bring desktop-class processing power directly to your applications. And the best part? We do all of this while strictly adhering to a zero server uploads philosophy. That means your users' sensitive documents are never needlessly bounced around the internet.
Why Local Processing is the Future of Tech
You've got this incredible responsibility to keep your users' data secure. But the real highlight of our approach is how it beautifully marries top-tier security with blazing-fast performance. When your application triggers a request to split a PDF, traditional APIs would require you to upload the entire file to an external server, wait for the processing to finish in a queue, and then download the result. That's a lot of unnecessary network overhead and a massive security vulnerability waiting to happen.
With our innovative localized processing architecture, everything happens securely within the client's own environment. This completely eliminates the terrifying risk of data breaches during transit. It's the kind of forward-thinking architecture that not only protects sensitive information but also dramatically reduces your server hosting costs. Your users get lightning-fast results, and you get the ultimate peace of mind knowing you aren't storing thousands of temporary files on your backend.
Seamless Integration for Any Project
We know that your time is valuable. You don't want to spend weeks reading through convoluted technical manuals just to figure out how to rotate a PDF document via an API call. That's why we've made our documentation as clear, concise, and conversational as possible. We use standard RESTful conventions that you are already deeply familiar with. It's that simple.
Whether you are building a massive enterprise document management system or a lightweight internal tool for your startup, integration is an absolute breeze. You just grab your API key, make a simple HTTP request, and you are immediately off to the races. We've purposely removed all the unnecessary friction so you can focus entirely on building amazing features for your own users instead of wrestling with formatting issues.
Built for Scale, Designed for Safety
As your application grows, you need infrastructure that can effortlessly scale right alongside it. Because our core technology relies so heavily on client-side processing, you will never have to worry about our servers becoming a bottleneck during your peak usage hours. The heavy lifting is elegantly distributed across your users' devices, ensuring consistently rapid response times no matter how much traffic you are currently handling.
We are incredibly passionate about pushing the boundaries of what is possible in the browser. We continuously update our core WebAssembly modules to be even faster and vastly more efficient. By choosing our API, you are not just getting a simple tool; you are partnering with a platform that is fully committed to the future of secure, decentralized web technologies. Go ahead and start building something truly awesome today—we can't wait to see what you create!