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Merge, split, compress, convert, and edit PDFs instantly. All processing happens in your browser – your files never leave your device.
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Most Popular PDF Tools
Quick access to our most-used features. All tools are completely free with no limits.
合并PDF
将多个PDF文件合并成一个文档。免费在线PDF合并器，支持拖放重新排序。...
拆分PDF
将PDF文件拆分成多个文档。提取特定页面或按页面范围分割。...
压缩PDF
减小PDF文件大小同时保持质量。免费在线PDF压缩器，生成更小的文件。...
编辑PDF
在线编辑PDF文件。添加文本、图像、注释、高亮和形状到您的文档。...
JPG转PDF
将JPG图像转换为PDF。将多个JPG文件合并成一个PDF文档。...
PDF转JPG
将PDF页面转换为JPG图像。高质量提取，可自定义分辨率。...
签署PDF
为PDF文档添加电子签名。绘制、输入或上传您的签名。...
加密PDF
为PDF文件添加密码保护。添加加密并设置权限。...
PDF Workflow Builder
Automate your PDF tasks by chaining multiple actions together. Create custom workflows that merge, compress, convert, and organize your documents in one go.
- Drag & Drop – Visually build your workflow with an intuitive editor
- Chain Actions – Combine merge, split, compress, convert in sequence
- Save Time – Process multiple files with a single click
110 Actions
Available in workflows
How It Works
Complete privacy. Zero uploads. Everything happens right in your browser.
Choose a Tool
Select from 110 professional PDF tools. Merge, split, convert, compress, and more.
Add Your Files
Drag and drop your PDFs. Files are processed locally in your browser for complete privacy.
Download Result
Get your processed PDF instantly. No waiting, no account required.
Why Choose pdftheory?
Trusted by millions of users worldwide for secure, fast, and reliable PDF processing.
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
No server uploads. Instant results without waiting in queues.
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Works Everywhere
Use on any device with a modern browser. Desktop, tablet, or mobile.