PDF SDK 101: What is a PDF SDK?

This article was first published in April 2023 and was updated in October 2024.

This post will explain what a PDF SDK is, what it can do, who it’s for, and how it can make your developers more productive and your users happier.

What is a PDF SDK?

A PDF software development kit (SDK) is a set of customizable components that enable software developers to quickly add advanced PDF functionality to any application, without the typical upfront investment. It helps companies go to market faster, streamline development, and improve profitability.

Modern PDF SDKs are complete, integrated platforms that enable you to bring viewing, annotation, editing, forms, signatures, collaboration, and much more to your web, mobile, server, cloud, and desktop applications.

All these functionalities are offered through a library that your developers build directly into your application. PDF SDKs are designed to be easy to use and lightweight, yet highly customizable.

What does a PDF SDK do?

Not too long ago, companies expected their users to download PDFs and work with them in specialized third-party applications. A lack of integration into their applications prevented people from quickly accessing and sharing up-to-date documents, in turn slowing their ability to collaborate, fill forms, review, approve, edit, and sign documents.

Fast forward to today, and PDF SDKs enable companies to offer these capabilities directly inside their applications, improving engagement while retaining greater control of documents. Meanwhile, the user interface (UI) is tailored to match the application’s look and feel, creating a seamless experience.

PDF SDKs also automate document workflows, such as PDF creation, conversion, editing, OCR, and more. In addition, they have built-in document analysis capabilities that are powered by artificial intelligence (AI) to accurately extract structured data from unstructured documents.

In other words, modern PDF SDKs give product and engineering teams a best-in-class foundation to take their applications and automations to the next level.

Some ways you can use PDF SDK capabilities to benefit your company include:

Benefits of a PDF SDK

PDF SDKs remove the technical complexity of building and maintaining PDF technology in-house, freeing you to focus on delivering value to your customers. They enable you to deliver more impactful product releases that can open up new markets and revenue streams while also optimizing costs.

PDF SDKs also enable you to build and deliver enterprise-grade features in days — not months or years — increasing agility while shortening time to value. And best of all, a PDF SDK ensures your applications are more versatile and useful for your users.

Here are a few other benefits that the right PDF SDK can offer you:

Who is a PDF SDK for?

A PDF SDK gives everyone — from product, development and customer support, to information security, legal, and any other team — a better way to work with PDFs and extend their applications with next-generation PDF capabilities.

PDF SDKs can help organizations of all sizes drive growth and efficiency, and they’re particularly relevant in challenging economic environments where companies need to do more with less.

Product management

PDF SDKs make a product team’s short-term roadmap more impactful, improving differentiation while opening new revenue streams. Once an SDK has been integrated, the product team has the flexibility to leverage the SDK’s existing and upcoming new innovations to further enrich future releases.

The right PDF SDK can empower product management to:

• Keep its roadmap on track.

• Go to market faster, with less risk.

• Focus on differentiation and value creation instead of building PDF software.

• Improve adoption and lower churn.

• Continuously innovate with leading-edge document technology.

Chief Technology Officer (CTO)

CTOs capitalize on a PDF SDK’s technical capabilities by not having to maintain specialized PDF expertise, which frees them to instead focus on value-added technologies.

The right PDF SDK can empower a CTO to:

• Do more with fewer development resources.

• Mitigate the risks involved in needing specialized in-house PDF expertise.

• Accelerate quality assurance (QA) and release cycles.

• Spend less time maintaining an assortment of independent PDF libraries.

• Deliver fast, reliable, and battle-tested PDF functionality.

Software developers

A PDF SDK ensures software developers can more efficiently build a proof of concept (POC), integrate the SDK, and develop code that leverages the capabilities of the SDK.

The right PDF SDK can empower software developers to:

• Deliver new and innovative capabilities faster.

• Spend less time debugging and refactoring.

• Ship battle-tested software with fewer bugs.

• Focus on more interesting projects that don’t require specialized expertise.

Customer support

PDF SDKs help a customer support team by reducing the number and severity of tickets. By getting access to a PDF SDK provider’s specialized PDF expertise, the support team can also resolve issues more quickly.

The right PDF SDK can empower customer support to:

• Spend less time managing support tickets for PDF-related issues.

• Provide a better support experience to users impacted by PDF-related issues.

Chief Information Security Officer (CISO)

A PDF SDK with independently verified security and privacy controls ensures CISOs can continue to minimize the risk of data breaches or cyber attacks. With many vulnerabilities originating from third-party components, embedding an insecure PDF SDK into your software is an unacceptable risk.

The right PDF SDK can empower a CISO to:

• Protect the organization and its users from vulnerabilities.

• Ensure the development of software follows best practices.

• Maintain the company’s overall security posture.

• Remain compliant with regulations and standards.

Legal

A PDF SDK with the right licensing model helps the legal team manage potential legal risks. This is particularly relevant for open source projects, which can have unfavorable licensing terms, as a large software vendor discovered when it integrated what it thought was a free open source PDF library.

The right PDF SDK can empower a legal team to:

• Ensure software licensing aligns with legal policies and requirements.

• Eliminate the need to share private or confidential data with third parties.

• Remain compliant with GDPR and other privacy regulations.

What industries can benefit from a PDF SDK?

A PDF SDK offers versatile functionality that can be applied across various industries. Here are some examples of industries that can significantly benefit from integrating a PDF SDK into their applications:

What types of PDF SDKs are available?

There are three main types of PDF SDKs available for developers. Here’s what each type has to offer your business.

Client-side PDF SDKs

A client-side PDF SDK enables developers to directly integrate PDF functionalities into web, mobile, and desktop applications that run on the user’s device without relying on an external server.

Client-side PDF SDKs can offer you:

• Lower infrastructure costs by offloading rendering, editing, processing, and conversion from your servers to the user’s device.

• Reduced maintenance from not having to deploy or maintain server infrastructure.

• Infinite scalability because processing is handled by each user’s device and isn’t dependent on finite server resources.

• Zero downtime, because it doesn’t require an internet connection, which is advantageous when working in remote areas or locations with unreliable connectivity.

• Improved privacy and compliance from not transmitting data over a network to a server. This is especially relevant in highly regulated contexts, such as financial services and healthcare, or when impacted by GDPR.

Nutrient offers fully client-side PDF SDKs for web, mobile, and desktop applications.

Server-side PDF SDKs

A server-side PDF SDK enables developers to automate document workflows on their web server or backend applications.

Server-side PDF SDKs can offer you:

• Improved performance for complex document processing because the application is being run on powerful servers with more horsepower than client-side devices.

• Better security because data isn’t transmitted to and from the client over a network. Server-side applications are often deployed on-premises, which adds another layer of protection.

• Greater control over documents and data.

• More flexibility when integrating with other systems or services because it can be easier to share data and functionality between different applications and services.

Nutrient offers server-side PDF SDKs for .NET, Linux, and Java.

Client- and server-side PDF SDKs

Client-server PDF SDKs can offer you capabilities that wouldn’t be possible with a pure client- or server-side model:

• Remote document access — The client authenticates with the server, which then dynamically serves the document, along with any annotations the user is allowed to access.

• Complex processing — Resource-intensive tasks are performed on the server, with the resulting output sent down to the client, improving performance.

• Universal document conversion — The user uploads any file type, which is then converted on the server and sent back down to the client.

• Real-time collaboration — Multiple users simultaneously highlight, add comments, or annotate a document, which is then synchronized in real time across users, devices, or sessions.

• Submitting PDF form data — The user inputs data into PDF form fields, which are then sent to a server for processing.

Nutrient offers client-server PDF SDKs for web, mobile, and desktop applications.

For a quick reference, review the following table to see the benefits of each type of PDF SDK:

What are the components of a PDF SDK?

PDF SDKs typically consist of a PDF engine, a core, and the user interface (UI). Here’s how each of these components contribute to the success of your application.

PDF engine

The PDF engine is the low-level component that parses and interprets the instructions contained within the PDF file, which may include text, files, images, and graphics.

The right PDF engine can offer you:

• Stronger security by reducing the vulnerabilities that can be exploited in PDF parsers (as a large software vendor discovered by using an insecure PDF engine).

• Higher rendering fidelity so all images in the PDF are displayed, the fonts are correct, colors are consistent, and patterns or gradients appear as intended.

• Faster load time for all types of PDFs, including large files, or those with complex graphical features.

• Fewer crashes that are caused by complex, malformed, or corrupted PDFs.

Nutrient’s PDF engine is based on an optimized fork of PDFium, the same battle-tested PDF engine used in Chromium and Android.

Core

A PDF SDK’s core provides a set of APIs for rendering, manipulating, and creating PDFs.

The right core can offer you:

• Faster development using APIs designed to match the target platform’s development paradigms.

• Greater flexibility and adaptability to a range of use cases and scenarios, reducing the need to create hacks or workarounds.

• Streamlined software maintenance by having stable APIs that don’t change, so your developers won’t need to regularly update the code.

At Nutrient, we put a lot of effort into ensuring our core APIs are stable and designed by experienced developers who are deeply familiar with the target platform.

User interface

If an SDK offers a viewer, its UI interacts with core APIs to perform operations like rendering and editing. In some cases, the UI will have its own separate set of APIs for customizing the appearance and behavior.

The right UI can offer you:

• Stronger security by minimizing the risk of attackers uploading malicious files, accessing restricted files, or performing an account takeover (as another large software vendor discovered by using an insecure open source UI).

• Reduced maintenance costs by ensuring your UI customizations are compatible with future releases and won’t require refactoring by your developers.

• A seamless user experience that can easily be customized to match your application’s look and feel and workflow requirements.

Nutrient offers a robust set of APIs to securely customize your UI’s appearance and behavior, without the headaches that come from maintaining customizations made to an open source UI.

Why is a PDF SDK transformative?

Digital documents are the currency of digital transformation, yet innovating with today’s digital documents has never been more difficult for developers. By removing this obstacle and enabling your developers to build on top of next-generation document technology, your velocity accelerates, as will the speed of innovation and transformation.

Modern PDF SDKs have already solved the PDF problem. Instead of reinventing the wheel, your product and engineering teams can focus on the things they do best and enjoy more innovating, collaborating, and building.

Why a PDF SDK is better than open source libraries

While open source PDF libraries are free, they often come with hidden costs in the form of maintenance, slower time to market, and potential licensing risks. In contrast, a commercial PDF SDK like Nutrient offers:

Why do companies choose Nutrient’s PDF SDK?

“What we really appreciate with Nutrient is the polish of this product. A great amount of time has been spent on the details.”

Most of our customers use our PDF SDK because they lacked the time, resources, or PDF expertise to deliver a new product, feature, or workflow. Our PDF SDK offers them a win-win solution, empowering them with the necessary tools and support to be successful, while enabling them to quickly apply PDF technology to solve a specific problem.

“Nutrient enables us to be the only one in our space to offer features like this.”

Getting started with Nutrient

Learn more about the capabilities Nutrient can bring to your application by exploring our interactive web demo, watching or registering for our webinars, and reading our customer stories. If you’re ready to get started, check out our free trial or get in touch, and one of our solutions engineers would love to show you why Nutrient is the right choice.

Summary

Simply stated, a PDF SDK is a set of tools and software libraries that allows developers to create, manipulate, and view PDF files within their own applications. It’s necessary to use a PDF SDK because most programming languages and frameworks don’t provide native support for PDFs.

This post outlined the various scenarios where PDF enablement is necessary, such as displaying a PDF on a website, allowing users to collaborate on a document, and generating a PDF as part of an automated process.

There are different types of PDF SDKs available, and the benefits of using a PDF SDK are numerous, including reduced cost and faster time to market, as well as the ability to use advanced PDF capabilities.

FAQ

How does a PDF SDK differ from a PDF API?

A PDF SDK (software development kit) provides a collection of tools, libraries, and prebuilt code for developers to integrate PDF functionality into applications with ease. It typically comes with detailed documentation, UI components, and ready-to-use features. Meanwhile, a PDF API (application programming interface) is a set of protocols or web-based interfaces that allow applications to interact with PDF functionalities remotely, usually over the internet. An SDK is often more comprehensive and may work offline, while an API is lightweight and operates through HTTP requests.

What are the top features of a PDF SDK?

The key features of a PDF SDK often include:

• PDF creation and editing — Easily generate and modify PDFs programmatically.

• Annotation tools — Add comments, highlights, and notes to PDF documents.

• Form handling — Create, fill, and manage interactive PDF forms.

• Document encryption — Secure PDFs with encryption, digital signatures, and password protection.

• PDF merging and splitting — Combine multiple PDFs into one, or split a PDF into individual pages.

• Text and image extraction — Extract text, images, and other data from PDFs for further processing.

Why should I use a PDF SDK for my application?

Using a PDF SDK allows developers to quickly integrate robust PDF functionality into their applications without building from scratch. It saves time, ensures reliability, and provides access to powerful PDF manipulation tools. This is especially useful for businesses that need to handle large volumes of documents or create applications that require document management, reporting, or form processing features.

What platforms support PDF SDKs?

Most PDF SDKs are cross-platform and support a variety of operating systems, including Windows, macOS, Linux, iOS, and Android. Additionally, many SDKs can be integrated into web applications using JavaScript, allowing for browser-based PDF functionality.

Is a PDF SDK suitable for enterprise-level applications?

Yes, PDF SDKs are highly suitable for enterprise-level applications. Many SDK providers offer advanced features like batch processing, enterprise-grade security, and scalability, making them ideal for businesses with extensive document handling requirements.