Stirling is the largest open-source PDF app.
We help individuals, companies, and governments work on PDFs safely at scale.
The Origin
Stirling's business was architected to solve a critical gap: How do you perform advanced operations on classified PDFs at scale?
Sending files to the cloud for OCR, redaction, or extraction was a security violation. Manual processing was impossible at scale. Industry leaders needed an option they could control.
The Architecture
We designed Stirling to pass the strictest security clearance and meet the highest volume requirements at the same time. Instead of relying only on external APIs, Stirling deploys a complete PDF processing core you can run on any infrastructure. All PDFs stay completely private.
The Standard
Today, Stirling is the open-source standard for private PDF operations.
Maintained by the engineers behind the world's most popular PDF container, our infrastructure now powers the Fortune 500, rigorous government agencies, and privacy-conscious developers worldwide.
Used by 75% of the Fortune 500
