List of the Top 25 SaaS PDF Annotators in 2025

Apryse, which was previously known as PDFTron, is transforming the document landscape. It enables precise viewing, annotating, editing, creating, and generating of PDFs across various platforms, including web, mobile, desktop, and server applications. The technology offered by Apryse is compatible with all leading platforms and supports a wide array of file formats, such as PDF, Microsoft Office, and CAD files. By implementing this solution on your own infrastructure, you can manage the entire document and data lifecycle without the need to rely on external server services. This independence allows organizations to enhance their workflows and maintain greater control over their document processes.

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.

Global OEMs, SaaS providers, and enterprise users utilize the Adobe PDF Library to streamline the processes of creating, editing, and managing PDF documents. As an authorized Adobe partner, our SDK is built using the same source code as Acrobat, ensuring top-notch stability, reliability, and quality. Supported programming languages include .NET, .NET Framework, Java, and C/C++, and it is compatible with platforms such as Windows, Linux, and MacOS, with package management facilitated through NuGet and Maven. The library boasts a wide range of capabilities, encompassing annotations, content creation and modification, color management, and various extraction options for text, images, and forms. It also offers features for compression, optimization, and conversion to formats like PDF/A, PDF/X, EPS, PostScript, XPS, and ZUGFeRD, along with robust display and printing options. Moreover, it allows for the import, export, and flattening of both static and dynamic XFA forms, along with AcroForms, and supports a variety of image operations including extraction, rendering, and thumbnail creation. The optimization functionality enhances file size and content, while OCR capabilities enable text addition to documents and images. Additionally, users can convert PDFs to Office formats such as Word, Excel, and PowerPoint, and implement security measures including viewer settings, redactions, password protection, encryption/decryption, and watermarking. Pricing structures are adaptable for OEMs, SaaS solutions, and end-users, based on their specific usage needs. Accelerate your development process and reach the market more swiftly with the Adobe PDF Library; take advantage of the free trial available for download today.

MobiPDF, previously known as PDF Extra, serves as a user-friendly platform for reading and editing PDFs, offering features such as creating, organizing, annotating, filling, signing, converting, and sharing any PDF file. This versatile tool stands out as a cost-effective substitute for Adobe Acrobat Pro, catering to a wide array of user needs. HERE’S WHAT YOU CAN EXPECT WITH MOBIPDF: Multiple Viewing Options: Utilize a focused "Read Mode" for an uninterrupted reading experience. Sophisticated Editing Capabilities: Engage with a PDF editing interface reminiscent of Word. Bidirectional Conversions: Effortlessly transform PDFs into and from formats like Word, Excel, PowerPoint, or images. OCR Integration: Enhance scanned documents by making them searchable. Annotation Features: Utilize tools to highlight, comment, strikethrough, stamp, and more to improve your documents. Simple PDF Management: Easily reorder, compress, split, and merge PDFs as you need. Signing and Security: Incorporate signatures, create and fill out forms, and safeguard your PDFs with passwords, encryption, and digital certificates. Offline Functionality: Continue working on your files without needing an internet connection. Instant Translation: Translate any PDF into over 50 languages with just a click. Overall, MobiPDF combines essential features and user-friendly design, making it a reliable choice for anyone needing comprehensive PDF tools.

SwifDoo PDF is a versatile tool for Windows that serves as a comprehensive PDF maker, reader, editor, and converter. It allows users to effortlessly create, convert, merge, compress, and sign PDF files while offering an intuitive interface that supports the insertion of links or images into documents. Users can convert PDFs into formats such as Microsoft Word, Excel, PowerPoint, JPG, PNG, TIFF, BMP, and even convert CAD files to PDF. The integrated compression feature ensures that files are reduced in size without compromising quality. Additionally, SwifDoo PDF boasts an array of specialized tools for scanning and converting documents, enhancing its functionality. Among its capabilities are PDF reading, annotation (including stamp features), image extraction, editing, compression, merging, splitting, and adding signatures to documents. This all-in-one solution is compatible with various Windows operating systems, including Windows 10, 7, 8, Vista, and XP. The current version available is SwifDoo PDF 2.0.1.9, making it a reliable choice for managing PDF files efficiently.

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!

Enhance your productivity with user-friendly PDF tools designed to streamline your workflow with PDF documents. These tools are completely free and straightforward to utilize! You can easily incorporate text, images, and freehand drawings into your PDFs, fill out forms, and even create a personalized signature for signing documents. Moreover, share your PDF files with confidence through a secure link that expires automatically, ensuring complete privacy with zero-knowledge end-to-end encryption using 256-bit AES technology. This way, your sensitive information remains protected while you collaborate!

Transform your PDF documents effortlessly by converting, editing, merging, and compressing them with just a few clicks. In just seconds, you can download your finished document without any complications, as our PDF converter works swiftly to generate files. To protect your digital information, we ensure the use of HTTPS encryption during your PDF creation process on our platform. You have the ability to redact documents, modify text, add new components, and perform many other functions, all from one convenient location. Our intuitive interface is crafted for easy navigation, enabling you to make the most of our PDF creator with minimal hassle. This online PDF tool is compatible across all major operating systems, delivering seamless performance on Windows, Mac OS, Linux, iOS, and Android devices. For added privacy, you can secure your files by locking or restricting access, which prevents unauthorized users from opening, editing, or printing them. This all-in-one tool not only streamlines your document management but also boosts your overall productivity and efficiency. By utilizing our platform, you can ensure that your PDF editing and handling needs are met without any unnecessary stress.

No matter if you are an individual, a corporation, a government entity, or an academic organization, engaging with PDFs—whether reading, creating, signing, annotating, or completing forms—is crucial. Foxit PDF Reader emerges as a lightweight, remarkably swift, and feature-rich PDF viewer that allows users to create PDFs at no cost, along with the ability to open, view, sign, and print any PDF file effortlessly. This software is driven by the industry's most rapid and accurate PDF rendering engine, guaranteeing an outstanding experience in both viewing and printing documents. It also boasts multilingual support, accommodating users in English, Dutch, French, German, Italian, Portuguese, Russian, and Spanish, which enhances its accessibility. Moreover, users have the convenience of signing documents using their own handwriting, leveraging eSignature capabilities, and easily checking the validity of digital signatures. In terms of security, Foxit PDF Reader integrates protective features such as Trust Manager/Safe Mode, ASLR & DEP, options to disable JavaScript, and Security Warning Dialogs, ensuring users are safeguarded against potential threats. Furthermore, it effortlessly connects with major cloud storage solutions and prevalent enterprise content management systems, rendering it an essential resource for various organizations. Its wide array of functionalities not only boosts productivity but also positions it as a favored option among users who prioritize efficiency and dependability when handling PDF documents. With its continuous updates and user-centric features, Foxit PDF Reader remains committed to enhancing the overall document management experience.

Take advantage of our complimentary Adobe Acrobat Reader to effortlessly view, sign, collaborate on, and annotate your PDF files. With this tool, you can not only view and sign documents but also collect feedback and share PDFs for free. If you wish to enhance your experience, you can subscribe to Acrobat Pro, which provides additional features such as editing, exporting, and sending PDFs for signature requests. Move beyond simply opening and viewing your PDF files; it's easy to annotate your documents and gather input from multiple reviewers into a single shared online PDF. The Acrobat Reader mobile app allows you to conveniently work on your documents from anywhere, equipped with essential tools for converting, editing, and signing PDFs. Moreover, the app lets you use your device's camera to scan documents, whiteboards, or receipts and turn them into PDFs. By connecting to Adobe Document Cloud, Acrobat Reader guarantees that your work with PDFs is accessible no matter where you are, and you can easily manage your files on platforms such as Box, Dropbox, Google Drive, or Microsoft OneDrive. This smooth integration offers a flexible and efficient workflow, enhancing your document management experience like never before, ensuring your productivity remains uninterrupted. Thus, whether you're working on a personal project or collaborating with a team, Adobe Acrobat Reader provides a comprehensive solution for all your PDF needs.

PDF.live provides the capability to transform PDFs into various file formats and vice versa, including Word documents, Excel files, PowerPoint slides, and JPEG images. It is a cloud-based tool that operates on any internet-connected device, eliminating the need for downloads or installations. Users can effortlessly drag and drop their documents while following the on-screen instructions to sign, annotate, and modify text. Additionally, this free online PDF editor offers features for compressing, merging, and managing your documents with ease. With its user-friendly interface, PDF.live ensures that all your document needs are met efficiently and effectively.

UPDF provides a comprehensive solution for editing, annotating, and managing PDF files across platforms like Windows, Mac, iOS, and Android. This versatile application consolidates all essential tools into a single user-friendly interface, designed to cater to the preferences of both novice and experienced users who appreciate an aesthetically pleasing layout. Among its key features, UPDF allows users to edit PDF documents by adding, deleting, and modifying text properties, including font style, color, and size, while also enabling image manipulation such as cropping, rotating, and extracting. Additionally, users can annotate PDFs by highlighting, underlining, or striking through text, and can easily insert shapes, sticky notes, and text boxes for improved communication. Another significant feature is the ability to manage PDF pages, which includes options to rotate, delete, and extract specific pages as needed. Furthermore, UPDF enhances the reading experience by offering various viewing modes, including both single-page and double-page formats, ensuring flexibility for all types of users. With such a robust set of functionalities, UPDF stands out as an invaluable tool for anyone working with PDF documents.

TinyWow provides an extensive selection of complimentary online tools focused on file conversion and PDF management, aimed at helping users tackle various tasks. To prioritize user confidentiality, any files—regardless of whether they have been processed—are deleted from the server within an hour. Users can effortlessly convert PDF documents into JPG images, enabling the download of each page as a separate image file. Likewise, TinyWow allows for the conversion of PDF files into PNG format, with each page also available for individual image downloads. This functionality makes TinyWow a practical and adaptable choice for anyone seeking swift and effective file conversion solutions, catering to diverse needs and preferences. Additionally, the user-friendly interface enhances the overall experience, making it accessible for individuals with varying levels of tech-savviness.

Enhance your applications with the versatile MuPDF SDK, which seamlessly integrates robust PDF capabilities. This compact yet swift viewer accommodates various document formats, including PDF, XPS, OpenXPS, CBZ, and ePUB. It features a renderer crafted for high-quality anti-aliased graphics, ensuring that text is displayed with precise metrics and spacing, accurate to mere fractions of a pixel. The PDF library comes equipped with a range of interactive functionalities such as annotations, form filling, digital signatures, redactions, and search capabilities. Furthermore, the command-line tools offer extensive customization options for rendering, converting documents, and manipulating PDF files, allowing for conversion to formats like HTML, SVG, and CBZ. In addition to its C library, MuPDF provides a Java library utilizing JNI, compatible with both Oracle's Java and Android platforms. Alongside the Java API, bindings for C++ and Python have also been established, showcasing its compatibility with major programming environments and operating systems. Its flexibility and optimization for various platforms make it a powerful tool for developers. The MuPDF API has found applications in a wide range of deployments, including mobile applications on both Android and iOS, SaaS and cloud solutions, document management systems, and various embedded products, highlighting its versatility and effectiveness in meeting diverse user needs.

PDFgear is a comprehensive PDF tool that enables users to view, edit, convert, sign, annotate, and organize their documents seamlessly across Windows, MacOS, and iOS platforms. With its intuitive and user-friendly interface, PDFgear ensures a smooth experience for reading and editing documents without any distractions. The PDFgear Copilot serves as an advanced personal assistant that surpasses the capabilities of a typical document assistant, utilizing AI technology to help users navigate all features of PDFgear and interact with their PDF files. If you find yourself overwhelmed by the multitude of functions or content within your documents, simply reach out to Copilot for assistance—it's there to answer any questions you might have! Working with PDFs feels effortless and enjoyable with PDFgear, making your tasks as pleasant as a leisurely walk through a beautiful garden. Explore the full potential of your PDF documents effortlessly with this innovative tool!

Xodo provides the capability to edit, annotate, and sign PDF documents seamlessly across desktop, mobile, or web platforms. This user-friendly tool simplifies PDF management, eliminating the hassles of printing or faxing altogether. Now, you can easily sign important documents like contracts, expense reports, and cover letters directly on your smartphone or tablet, using just your finger or a stylus. The process is incredibly straightforward! With Xodo, signing any document requires merely a tap, freeing you from the hassle of searching for a pen or dealing with messy ink. You can also conveniently save your signature for future use, allowing you to sign documents with just a single tap or mouse click. Once you're done, saving and sharing the file with others is a breeze, significantly reducing the time spent in email exchanges. Xodo effectively alleviates the stress associated with completing forms. Using your smartphone or tablet, you can fill out forms from virtually anywhere by simply tapping on the screen and selecting checkboxes. This innovative approach allows you to save both time and effort, making it easier than ever to fill out and share forms on the go. With Xodo, managing your paperwork has never been more efficient or hassle-free!

Wondershare HiPDF is an innovative online PDF tool enhanced with AI capabilities, offering an extensive array of functionalities, including chatting with PDFs, AI reading, editing, converting, OCR, signing, and managing PDF documents, along with various image editing tools. The platform is user-friendly and comes with a free plan, enabling users to effortlessly summarize, explain, rewrite, merge, split, compress, convert, rotate, unlock, and secure PDF files in just a few clicks. As a recognized member of the PDF Association and holder of esteemed certifications like ISO 27001 and SSI SECURE, HiPDF prioritizes both ease of use and security, having successfully processed millions of documents to date. Highlighted Features: AI reading: Engage with PDFs through summarization, rewriting, explanations, and interactions with the AI PDF reading assistant. Document Conversion: Seamlessly convert PDF files to and from various Microsoft Office formats or images. PDF Merging: Effortlessly combine multiple PDF documents online. Size Compression: Easily reduce the size of PDF files through an online platform. Electronic Signing: Fill out and sign PDFs securely from any device at any time. PDF Protection: Safeguard sensitive information by restricting copying, editing, printing, and viewing with password protection. Overall, HiPDF stands out as a comprehensive PDF solution that balances functionality with user security.

Conholdate.Total serves as the all-encompassing toolkit for every .NET API provided by Aspose and GroupDocs, empowering developers to execute an extensive range of document processing functions within their .NET applications. This comprehensive package offers integrated solutions tailored for various document management systems, enabling users to create, modify, print, view, sign, compare, automate, and convert a diverse array of widely-used document formats. With Conholdate.NET, you can seamlessly handle numerous file types, making it simple to open, edit, and convert files with ease. Currently, Conholdate.Total.NET is compatible with an impressive array of file formats, which includes Microsoft Word documents, Excel spreadsheets, PowerPoint presentations, Adobe PDF files, Outlook items, Microsoft Project files, and over 100 additional formats, making it an invaluable resource for developers. Its versatility ensures that users have the tools necessary to manage their document workflows effectively.

LightPDF was designed to simplify the handling of PDF documents for users of all levels. With its user-friendly interface, this software enables individuals to effortlessly read, edit, and convert PDF files. The integrated editing features of the program include: 1. Editing capabilities: You can modify your PDF by adding text, annotating, and inserting hyperlinks, as well as incorporating headers or footers. 2. Conversion options: Easily convert PDF files into formats like Word, Excel, PPT, or JPG. 3. Page management: You have the ability to insert or delete pages, rotate them, and perform actions like extracting, replacing, splitting, or merging pages. 4. Signing features: Users can add either a handwritten signature or a digital signature to their PDFs. 5. Security measures: Protect your documents by adding a password to lock your PDF files. 6. Additional functionalities: The software also includes features such as OCR for text recognition, PDF compression, and background addition, among others, making it a versatile tool for various PDF needs.

Effortlessly generate and manage PDF files by leveraging features such as splitting, appending, stamping, encrypting, extracting, and filling. PDFKit.NET serves as a comprehensive .NET class library tailored for the creation and modification of PDF documents, conveniently packaged as a single assembly that allows for simple xcopy deployment. It functions autonomously, requiring nothing more than the .NET framework. Central to PDFKit.NET is an intuitive and organized object model that includes various classes, such as document, page collection, page, canvas, shape, bookmark, annotation, and field. The development team's main objective is to streamline the integration of this class library into larger software solutions. With the introduction of PDFKit.NET 5.0, users can easily fill in text fields, checkboxes, and radio buttons, while choosing to save forms in either an editable format or as a flattened PDF. Moreover, this version brings forward the capability to manage dynamic XFA documents via a new XFA processor API, significantly improving functionality. Additionally, PDFKit 5.0 allows users to extract all graphics from a page, compiling them into a diverse collection of shapes that may include text, images, and curves, thus offering flexible options for document manipulation. This makes PDFKit.NET an essential tool for developers seeking to embed powerful PDF handling features within their applications. The continual updates to PDFKit.NET ensure that it remains at the forefront of document processing technology, catering to the evolving needs of users.

Discover an innovative online platform specifically created for managing annotations from PDFs and Kindle, aimed at significantly reducing the time spent on tedious tasks. You can quickly download your annotations from both PDFs and Kindle in various formats in a matter of seconds. Our service adeptly summarizes annotations from PDF documents, Kindle books, and Instapaper articles, thus relieving you of the hassle of finding an effective annotation management tool. Sumnotes distinguishes itself as a user-friendly yet robust option for extracting annotations from diverse sources, including PDF books, lecture notes, and research papers, enabling you to focus on what is truly important. By simply clicking a button, you can import and sync annotations across multiple platforms effortlessly. Moreover, our batch import functionality allows for the convenient addition of your entire library in one go. We proudly accommodate PDF files annotated with any recognized PDF software, such as Adobe and Preview on Mac systems, and we are excited to introduce our new feature that supports Kindle highlights as well! This tool is set to revolutionize how you engage with your reading materials, making your annotation process smoother and more efficient than ever before. It's time to take control of your annotations like never before!

DeftPDF is a comprehensive online PDF editor that eliminates the need for subscriptions or installations, enabling users to effortlessly edit and convert their PDF documents in just a matter of clicks. This user-friendly tool streamlines the process, making PDF manipulation accessible to everyone.

SmartOffice enables users to view, edit, create, and print Microsoft Office and PDF documents directly from their mobile devices, while SmartOffice PDF specifically provides features to view, annotate, and highlight PDF files. Additionally, users can convert Office documents into PDFs, saving them to their mobile devices or cloud accounts, and print wirelessly to thousands of compatible printers. The SmartOffice Mobile App serves as a comprehensive alternative to MS Office 365 and is available for download on both Google Play and the App Store for personal use, with options for enterprise users to integrate the app within a security platform to enhance mobile productivity. Furthermore, the SmartOffice SDK offers a variety of solutions that can be effortlessly incorporated into your enterprise's document workflow, allowing for seamless integration with your EFSS or MDM systems. This flexibility ensures that the SmartOffice mobile app can be effectively utilized within a secure enterprise environment, making it a valuable tool for businesses looking to enhance their document management processes.

PDFKit is a highly adaptable library that enables the generation of PDF documents seamlessly in both Node and browser environments, allowing for the effortless creation of complex, multi-page, printable documents. Its user-friendly API supports chainable functions and offers both low-level capabilities and higher-level abstractions, streamlining the document creation process. With just a few function calls, users can craft sophisticated documents quickly and efficiently. The library also incorporates a range of access permissions, granting options for printing, copying, modifying, annotating, filling forms, ensuring content accessibility, and assembling documents. Accessibility is a priority, as the tool supports features such as marked content, a coherent structure, Tagged PDF, and compliance with PDF/UA standards. Furthermore, PDFKit is designed to work seamlessly with JPEG and PNG images, including support for indexed PNGs and those with transparency. In addition to utilizing PDFKit, it is essential to have a destination for streaming the generated output. For projects that employ PDFKit via Browserify, installing the brfs module through npm is a necessary step for loading built-in font data into the library. The robust combination of these features positions PDFKit as an invaluable resource for anyone seeking to produce detailed and professional-quality PDF documents with remarkable efficiency, making it a top choice for developers and designers alike.

This toolkit for processing and cleaning documents and images empowers developers to seamlessly incorporate various document handling features, such as image editing, compression, and enhancement, into their software. With ImageGear, applications can efficiently perform tasks like deskewing and removing lines and speckles from files, ensuring that images are clear and professional. The advanced color-processing capabilities of ImageGear enhance image quality while also minimizing the size of compressed files. This software development kit (SDK) offers a wealth of APIs designed for thorough image processing and cleanup, making it easier than ever to enhance application functionality. Additionally, ImageGear is instrumental in fulfilling all aspects of the document lifecycle, allowing .NET developers to integrate strong PDF features into their applications. Users can not only view and annotate PDF pages but also compress them to improve efficiency. Explore the extensive PDF manipulation features provided by ImageGear to elevate the performance and functionality of your applications even further.