PDF documents are part of everyday life: contracts, invoices, proposals, forms and manuals – they are all stored, shared and archived as PDF. But as soon as a PDF file needs editing, things often get complicated. Proprietary software like Adobe Acrobat is expensive, and many free online services send sensitive documents to servers in the USA or other countries outside the EU without users realising.

Stirling PDF offers a fundamentally different approach: an open-source web application with over 50 professional PDF functions that runs entirely in the browser. As a hosted instance with us, you receive a fully isolated environment on German servers – no data sharing, no tracking, no risk.

Over 50 Functions for Every Requirement

• Merge and split: Combine multiple PDFs into one document or extract individual pages as a new file.
• Compress: Reduce file size without significantly affecting visual quality – ideal for email or archiving.
• Convert: Convert PDFs to images, Word, Excel or other formats. Also convert documents and images to PDF.
• Edit pages: Rotate, rearrange, delete, duplicate or insert blank pages.
• Watermarks and stamps: Add text or image watermarks – for drafts, confidentiality or copyright.
• Password protection: Encrypt PDFs, password-protect them or remove existing protection.
• Digital signatures: Add visible or invisible digital signatures.
• Redact text: Permanently and irreversibly remove sensitive text passages – for data protection and compliance.
• Forms: Fill in or edit PDF forms where not protected.
• Metadata: Check and edit title, author, keywords and document properties.

Why a Hosted Instance?

Public PDF online services process your documents on third-party servers – often without transparent privacy policies. For sensitive documents such as contracts, personnel files or medical reports, this poses a significant risk.

• Complete isolation: No connection to external Stirling PDF instances or third parties.
• No data storage: Uploaded files are not stored after processing.
• Custom domain: The instance is accessible under your subdomain – with a free SSL certificate.
• No installation: Open the browser, upload the PDF, edit it – done.
• No maintenance: Updates and server management are handled entirely by us.

Who Is Stirling PDF For?

• Companies and law firms: Securely edit contracts, proposals and confidential documents without sharing data with third parties.
• Schools and educational institutions: Compile worksheets, compress scans, edit student data – all privacy-compliant in the browser.
• Government and public institutions: GDPR-compliant PDF editing without cloud exports – on servers in Germany.
• Associations and NGOs: Edit membership applications, invoices or notices with ease – without expensive software licences.
• Freelancers and self-employed: Professional PDF tools at a fraction of the cost of commercial alternatives.

Data Protection and Security

Your Stirling PDF instance runs in a protected container on servers in Germany housed in TÜV-certified, ISO 27001 compliant data centres.

• Full GDPR compliance
• DPA (Data Processing Agreement) included
• Encrypted data transmission via TLS/SSL
• No data sharing with third parties
• No storage of uploaded files after processing
• Fully isolated container environment

Stirling PDF vs. Adobe Acrobat and Online Services

Frequently Asked Questions

Are my files stored after editing?
No. All uploaded files are used exclusively for processing and then automatically deleted. No permanent storage takes place.

Can I use Stirling PDF under my own domain?
Yes. After setup, you can assign a custom subdomain. The SSL certificate is provided free of charge.

Do I need technical knowledge?
No. Stirling PDF is fully browser-based and intuitive. Open the application, select the desired function and upload your PDF – nothing more is needed.

Which functions are included in the Community Edition?
The CE includes over 50 functions: merging, splitting, compressing, converting, rotating, watermarks, password protection, signing, redacting and many more. All functions can be tested in advance in our demo.