150+ professional tools
Edit, organise, convert, redact, sign, compare and more, all in one application.
100% FREE Open Source. Available on Win 10 & 11.
Monstera PDF Editor
Every PDF tool you need without the subscription.
Monstera is a professional PDF editor with over 150 tools and an AI assistant, completely FREE and open source. Available on the Microsoft Store for Windows 10 and 11. No subscription. No account. No watermark.
Free forever. No trial. No subscription. Open source. Published by Tenslor Inc.
Why Monstera
Secure Sandboxed
Documents open inside an isolated sandbox and stay local on your PC.
Built-in AI assistant
Ask about your document using your chosen AI provider along with your API key (BYOK).
Free and open source
No subscription. No paid tier. No watermark. Source code available on GitHub.
150+ Professional PDF Tools
Monstera has over 150 professional PDF tools to meet your needs.
- Edit text in place
- True redaction
- Sign and verify
- OCR in 14 languages
- Handwriting to Excel
- Fill and build forms
- Merge and split
- Compare documents
- To Word, Excel and PowerPoint
- Compress
- PDF/A
- Passwords and permissions
- Annotate and stamp
- Built-in stamps
- AI with ten providers
- Translate a page in place
- Find and redact
- Office files to PDF, offline
- Bates numbering
- Measure to scale
- Accessibility checker
Built for the way you work
Business
Contracts, reports, invoices, proposals and internal documents.
Students
Research papers, scanned notes, forms and study material.
Legal and compliance
Redaction, signatures, document comparison and PDF/A archiving.
Finance
Statements, reports, forms and large document sets.
The obvious question
Why is Monstera free?
Because we chose to build it that way. Monstera is developed and published by Tenslor Inc., and released under the AGPL 3.0. There is no paid tier, no advertising and no business model built on your documents.
Development is funded by your voluntary donations.
- No subscription
- No account creation
- No advertising
- No watermark on your documents
- Full source code available
Frequently Asked Questions
Is Monstera really free?
Yes. No trial, no subscription, no paid tier, no watermark, no page limits and no account. It is free and open source.
Does it work offline?
Yes. Editing, forms, OCR, redaction, signing and conversion all run on your own PC with no internet connection. Only optional features you switch on, such as the AI assistant or cloud storage, need a connection.
Can it edit the text already in a PDF?
Yes. Click a paragraph and retype it. Monstera changes only that paragraph and leaves the rest of the page exactly as it was. New words keep the original font wherever it has the letters; otherwise Monstera uses the closest matching font, so an edit is never refused.
Are my documents uploaded anywhere?
No. Monstera has no server that receives your documents, and your documents stay on your computer by default. AI features you turn on send data directly to the provider you choose.
Does it run on Mac, Linux or phones?
No. Monstera currently only supports Windows 10 and 11. We hope to make it available on other platforms in the future.