List of the Top 9 On-Prem PDF APIs in 2025

Pdftools offers robust solutions for handling vast numbers of documents, potentially reaching into the millions. Tailored for sectors that heavily rely on documentation, the Pdftools suite of SDKs aims to enhance the speed, simplicity, and overall ease of your document workflows, reducing stress along the way. Built on reliable SDKs and APIs, Pdftools products integrate effortlessly into your current systems and applications. With the capacity to process thousands of documents each minute, our tools prioritize speed and efficiency. As engineers committed to excellence, we ensure that only the most trustworthy, usable, and well-documented platforms are utilized. While file sizes can be minimized, we guarantee that quality and interactivity remain intact. Additionally, our solutions help ensure that your documents adhere to long-term archiving standards. Comprehensive documentation accompanies every aspect of our products, allowing for a seamless onboarding experience. With Pdftools, you can transform your document management approach and unlock new efficiencies.

Enhance your website's capabilities with RAD PDF, an installation-free solution for PDF editing, form filling, redaction, signing, viewing, and much more! Designed as a user-friendly library/WebControl that works seamlessly with .NET 3.5+, .NET Core, and .NET 5+, RAD PDF is compatible with various ASP.NET frameworks such as MVC, Razor, Blazor, and WebForms. This powerful tool supports 99% of internet browsers across platforms including Linux, Mac OS X, Microsoft Windows, and mobile devices, eliminating the need for plugins or Adobe Reader. More than just a PDF to HTML converter, RAD PDF fully supports essential PDF features such as annotations, bookmarks, form fields, and page labels. With sophisticated PDF options, users can selectively enable or disable features not accessible through Adobe Acrobat Reader, such as restricting PDF download while still permitting online viewing. Moreover, RAD PDF allows users to fill out and save PDF form fields directly through their web browsers, streamlining the process without requiring any software installation. By integrating directly with ASP.NET, RAD PDF empowers your web application to collect input data, create tailored workflows, and offer an intuitive graphical user interface for virtually any online PDF interaction you can envision! Experience the convenience of RAD PDF and elevate your website's PDF handling capabilities today!

Nutrient offers a comprehensive suite of solutions tailored to meet all your PDF needs, providing tools that effortlessly handle PDF functionalities on any platform. 1. SDK: Integrate sophisticated PDF capabilities into iOS, Android, Windows, the web, or any cross-platform technology, offering features such as PDF viewing, annotation, collaboration, and much more. 2. Libraries: Use our robust .NET and Java libraries to empower your backend systems with capabilities for batch processing of redactions and PDF forms, OCR for scanned text, and editing of PDF documents, all directly from your application server. 3. Processor: Our nimble PDF microservice, Processor, facilitates the quick creation of PDFs from HTML, including HTML forms, alongside conversions from Office to PDF, OCR processing, redaction, and the combination and exporting of XFDF. 4. PDF API: Leverage our hosted PDF API to create, convert, and modify PDF documents within your workflows. We manage the development and server operations, allowing you to focus solely on growing your business. At Nutrient, we see ourselves not merely as a tool but as a dedicated partner in your journey to success. You can easily reach out to our engineers for specialized support, access thorough examples to aid in integration, and utilize our premium documentation to maximize your experience. Additionally, we are committed to continuous improvement and innovation, ensuring our solutions evolve with your needs.

MindCloud serves as a contemporary iPaaS and offers a comprehensive service solution tailored for small to medium-sized enterprises, allowing you to manage projects without the need for dedicated technical personnel. With an extensive library of over 50 pre-built connectors, we can also incorporate any new software platform equipped with an API or supports automated data imports and exports. In addition, we facilitate EDI and FTP integrations to enhance connectivity. Notable connectors include Salesforce, Monday.com, Hubspot, QuickBooks Desktop, QuickBooks Online, Method:CRM, Zapier, Walmart, Amazon, Overstock, eBay, Groupon, Mercado Libre, HSN, Airtable, Google Sheets, and a wide array of others. MindCloud empowers you to automate all your business processes effectively, thereby eradicating the need for redundant data entry. By integrating your business operations, you can streamline your workflow and improve your overall productivity, making your life easier in the process.

PrizmDoc empowers web developers to incorporate secure and dynamic HTML5 document viewing and editing functionalities, along with native spreadsheet capabilities, directly into their web applications or system solutions. Its remarkable adaptability ensures support across almost any platform and programming language that can perform REST API calls. Users can easily activate or deactivate key features based on the specific requirements of their applications, and implement user-specific permissions to safeguard proprietary information. Additionally, customization of the UI layout and style is available to enhance user experience. PrizmDoc can either be self-hosted within your own infrastructure or utilized via a fully managed backend provided by Accusoft’s public or private cloud services. Furthermore, Accusoft offers exceptional support through its Enablement Services, facilitating a smooth implementation of PrizmDoc for all users. This comprehensive flexibility and support make PrizmDoc an ideal choice for modern web development needs.

Watermarking PDFs, adding content to PDFs, querying PDF documents, converting files into PDFs, turning PDFs into images, adjusting PDF colors, and creating PDF/A and PDF/X formats are just a few of the features available; additionally, you can compress, linearize, and flatten PDFs, as well as merge or split them, encrypt, decrypt, and restrict access to PDFs, extract text, perform OCR on PDFs, upload files, and zip them as needed. Our robust RESTful API is now fully operational, enabling you to efficiently develop your own products and solutions without the need to start from scratch, while providing you with comprehensive control over your backend infrastructure. With our private cloud service, you can oversee every aspect of the process, ensuring full management of your documents. The pdfRest API Toolkit can be quickly configured through the AWS Marketplace, allowing you to set up a self-hosted, production-ready server that integrates seamlessly with your services or automates your internal document workflows. We offer flexible pay-as-you-go pricing plans, catering to businesses that demand complete ownership of their backend systems with minimal or no external server interactions. Moreover, by creating an EC2 instance to host our API, you gain total ownership over all files stored on your server, thereby enhancing your operational security and efficiency. This approach empowers you to tailor your document management solutions exactly to your needs.

ComPDFKit provides a high-quality PDF SDK, API, and Server tailored for businesses, organizations, startups, and developers alike. Its platform allows seamless integration of features such as document annotation, editing, conversion, form filling, and signing into various applications or products, which ultimately helps in reducing both time and costs. The software is versatile and works across multiple operating systems, including Windows, Web, Android, iOS, Mac, and Linux, as well as supporting cross-platform frameworks like React Native, Flutter, and Electron with minimal coding effort. Recent updates from ComPDFKit include the following enhancements: 1. ComPDFKit API Register now to receive 1000 free file processing each month, allowing for comprehensive editing and converting of PDF documents, as well as functionalities such as splitting, merging, inserting, rotating, deleting, and extracting PDF pages, alongside OCR processing. 2. Free Online Tools Utilize ComPDFKit's online tools to effortlessly convert PDF files to and from various formats, including docx, xlsx, pptx, png, jpg, html, txt, csv, and rtf. 3. Web Demo Explore the online demo to view, edit, annotate, compare, sign, encrypt, decrypt, watermark PDFs, and create or fill out PDF forms at no charge. 4. Community License Start-up companies and individual developers can benefit from competitive pricing options through ComPDFKit, helping you to develop customized applications while enjoying exclusive discounts and offers. Additionally, the user-friendly interface and comprehensive support further enhance the experience for developers looking to leverage PDF functionalities in their projects.

Enhance your application with PDF functionalities by utilizing just two API calls: Open, Edit, and View PDF. With a simple configuration file and these API calls, you can enable your app to swiftly import, view, modify, and open PDF documents within a single day. The SDK is designed to bridge format discrepancies, offering features such as cropping, color management, fills, and font adjustments. It facilitates the conversion of any PDF versions, including the ISO Standard PDF 2.0, allowing for versatility with any PDF file or print-ready document as an input. The conversion process is streamlined, ensuring a smooth experience without any intermediary steps or loss in quality, and it eliminates the need for a printer driver. Compatible with Windows, MacOS, and Linux, the PDF Conversion SDK also supports .NET and comes with sample code for your reference. Additionally, it effectively removes unnecessary data and compresses files, leading to enhanced performance during web and application browsing, making it an efficient choice for developers. By adopting this technology, you can significantly improve the user experience when handling PDF files.

The Aquaforest SDK is a comprehensive toolkit tailored for PDF processing, featuring capabilities such as content extraction, the creation of searchable PDFs, and advanced OCR functionalities that utilize both the standard Aquaforest engine and the upgraded Canon IRIS engine, as well as handwriting recognition through Google and Microsoft APIs. It includes a powerful PDF and barcode toolkit optimized for performance, capable of utilizing up to 64 processing cores for various tasks. This SDK enables efficient analysis of PDF documents, automating the extraction of name/value pairs for subsequent applications. Among its extensive manipulation options are features for merging PDFs, managing attachments, extracting content, processing XMP metadata, and ensuring PDF/A compliance, among others. The standard OCR engine remarkably supports 23 languages and is accessible across all SDK versions, which enhances its versatility in multiple contexts. In addition, the tool integrates effortlessly with cloud OCR services from Google and Microsoft, providing significant advantages for specialized tasks like handwriting recognition. The SDK also excels in reading and identifying a diverse array of standard barcode formats, further expanding its potential use cases in various industries. With continuous updates and improvements, the Aquaforest SDK remains a leading choice for developers seeking robust PDF processing solutions.