Annotate PDF documents online - AI tools

PDF Bob is a free online PDF editor that allows users to edit, annotate, create, and manage PDF documents without watermarks or ads.

• Free

I, Librarian is an online reference manager and PDF organizer that centralizes document storage, enables full-text search, and facilitates private group collaboration for students and research professionals.

• Other

Afirstsoft PDF is an AI-powered PDF editor for creating, editing, converting, annotating, and organizing PDF documents across multiple platforms, featuring AI summarization and chat.

• Freemium

Annotations is a Mac application that simplifies document annotation with highlights, keywords, and notes while maintaining document clarity, designed for researchers, students, and data analysts.

• Free

Xodo is an all-in-one document solution offering powerful tools to manage, edit, convert, and sign PDFs, Office files, and images across web, desktop, and mobile platforms.

• Paid
• From 10$

PDF Reader Pro is an all-in-one PDF solution for viewing, editing, converting, annotating, and form-filling across Mac, Windows, iOS, and Android. It integrates AI features like translation, summarization, and rewriting to enhance document workflows.

• Pay Once

PDF to Handwritten is a free online tool that converts text-based PDFs into handwritten-style text. Choose from multiple handwriting fonts, customize ink color and page layout, and preview in real-time.

• Free

GoodAnnotations provides AI-powered tools for drawing, editing, and annotating PDFs and screenshots to boost productivity and collaboration in digital workflows.

• Other

HiPDF is a comprehensive online PDF tool offering editing, conversion, compression, and merging features, enhanced with AI for summarization, translation, and interaction.

• Freemium

iLovePDF is a comprehensive online platform offering a full suite of PDF editing, conversion, and management tools designed to streamline document workflows for individuals and businesses.

• Freemium
• From 9$

Hylinker is a browser extension that enables users to annotate webpages and PDFs, connecting notes, images, and videos with bi-directional links. It supports integration with popular note apps, offering both offline-first capabilities and real-time synchronization across devices.

• Freemium
• From 2$

Smallpdf offers a suite of 21 tools to convert, compress, edit, and sign PDFs for free. Simplify your document management with a user-friendly interface and secure processing.

• Free Trial

PDF PDF offers a comprehensive suite of free online tools for all your PDF needs, including conversion, merging, splitting, compression, and more.

• Free

Sejda is a comprehensive PDF editing and management platform offering over 30 browser-based tools for tasks like editing, merging, splitting, converting, compressing, and securing PDF documents.

• Freemium
• From 8$

ILovePDF3 provides a comprehensive set of free online tools for editing, converting, and managing PDF documents, images, and other file formats, catering to both individuals and businesses seeking simple digital document solutions.

• Free

Scribble Together is a collaborative online whiteboard tool that enables real-time drawing, handwriting equations, diagram creation, and PDF markup across devices, with seamless sharing and no registration required for guests.

• Freemium
• From 5$

PDFAid is a comprehensive online PDF solution offering over 50 free tools for editing, converting, and signing PDF documents with powerful OCR capabilities and cross-platform accessibility.

• Free

PDF Buddy is a secure, web-based PDF editor that allows users to edit, fill, sign, and manage PDF documents directly in their browser. The tool offers convenience, safety, and an eco-friendly solution for managing PDFs without any software installation.

• Freemium
• From 8$

Advanced PDF Editor is an all-in-one PDF editing solution for Mac, offering over 40 features to edit, merge, convert, sign, and secure PDF files with ease and efficiency.

• Freemium
• From 4$

DeepPDF is an AI-powered tool for interacting with PDF documents. It allows users to chat with PDFs, summarize content, translate, analyze images and formulas, and convert files, simplifying research and document management.

• Freemium

UPDF is an AI-powered PDF editor available across multiple platforms (Windows, Mac, iOS, Android). It offers a comprehensive suite of PDF tools and AI features.

• Freemium

Online2PDF offers a robust suite of PDF conversion, editing, and management features for free, supporting multiple file formats and advanced customization options.

• Free

Highlights is an AI-powered PDF reader and research tool that transforms PDF annotations into organized notes with features like multilingual OCR, citation lookup, and smart export capabilities.

• Freemium
• From 5$

API2PDF provides a powerful REST API enabling developers to generate, convert, and manipulate PDFs and documents at scale using leading rendering engines and serverless infrastructure.

• Usage Based
• From 1$

ComPDFKit provides comprehensive PDF SDKs for developers, enabling integration of PDF viewing, annotation, editing, conversion, and AI-driven document processing functionalities into applications across multiple platforms.

• Free Trial
• From 67$

PDFBeat is a comprehensive online PDF toolkit offering free tools to edit, convert, merge, and organize PDF documents with fast performance and secure processing.

• Free

Macro is an AI-powered PDF reader designed to transform academic, legal, and finance documents into interactive and intelligent resources, enhancing understanding for professionals.

• Contact for Pricing

YellowPDF is an AI-powered online tool that offers a comprehensive suite of PDF management features including merging, splitting, compressing, converting, editing, and securing documents.

• Other

Win PDF Editor is a Windows-based PDF editing software that enables users to modify PDF documents by adding text, inserting images, drawing shapes, removing content, deleting pages, and redacting confidential information. It also includes a PDF converter for transforming documents into various editable formats.

• Other

DocHub simplifies document workflows with online PDF editing, e-signatures, and form creation. It offers seamless integration with Google Workspace and robust security features.

• Freemium