Stirling PDF is an open-source, self-hostable platform designed to give users full control over their PDF workflows without relying on third-party cloud services. It provides a comprehensive suite of 50+ PDF manipulation tools — including editing, merging, splitting, redacting, signing, converting, and OCR — accessible via a web interface, desktop app, or private API. Built with TypeScript and containerized for easy deployment, it caters to developers, DevOps teams, and privacy-conscious users who need to process sensitive documents on-premises or in private clouds. The open-core model ensures core functionality remains free and open while offering enterprise features through paid plans.
Its multi-platform support allows users to run Stirling PDF as a local desktop application, in-browser web app, or on servers using Docker or Kubernetes. With built-in SSO, auditing, and REST APIs for integration, it’s ideal for teams needing secure, scalable PDF automation without exposing documents to external services.
What You Get
- 50+ PDF tools - Includes editing, merging, splitting, signing, redacting, converting to/from images/HTML/PNG/JPG, OCR with text extraction, compression, and watermarking — all available in a single interface.
- Self-hosted deployment - Run Stirling PDF locally or on your server using Docker with a single command; no data leaves your environment.
- Private API access - Expose REST APIs for all PDF operations to integrate with existing systems, automate batch processing, or build custom workflows.
- Multi-device access - Use the web interface from any browser, deploy as a desktop app for offline use, or host on servers for team access.
- Enterprise-grade features - Supports SSO authentication, audit logging, and flexible on-prem deployments for compliance-sensitive environments.
- Global UI with 40+ languages - The interface is fully localized to support users across international teams and regions.
- No-code workflow builder - Create PDF processing pipelines directly in the UI without writing code, enabling non-technical users to automate tasks.
Common Use Cases
- Building a secure document processing workflow for legal firms - Law offices use Stirling PDF to redact sensitive information from case files and sign contracts without uploading documents to cloud services, ensuring compliance with GDPR and HIPAA.
- Creating a multi-tenant PDF conversion SaaS backend - Developers integrate Stirling PDF’s REST APIs into their platforms to offer PDF-to-Word, OCR, or merging services to customers while maintaining full data control.
- Automating invoice processing for finance teams - A company receives 10,000+ scanned invoices monthly; they use Stirling PDF’s OCR and batch conversion tools to extract text, rename files, and store them in their ERP system via API.
- DevOps teams managing PDF automation at scale - Teams deploy Stirling PDF on Kubernetes to handle high-volume PDF transformations across microservices, with containerized scalability and monitoring via Prometheus.
Under The Hood
The Stirling-PDF project is a full-stack PDF manipulation platform designed to provide extensive document processing capabilities through a modern web interface. It combines backend Java services with a responsive frontend to deliver a powerful and flexible PDF handling solution.
Architecture
This project adopts a monolithic architecture with clear separation between backend and frontend components, enabling flexible deployment and integration.
- The system is structured around layered components for PDF processing, configuration, and user interaction
- Modular design principles support extensibility and multi-tool integration
- Core functionalities are organized into well-defined modules with distinct responsibilities
Tech Stack
The project leverages a modern full-stack tech stack to deliver robust PDF processing features.
- The backend is built with Java and Spring Boot, while the frontend uses TypeScript and React with Vite for build management
- Key dependencies include Apache PDFBox, LibreOffice, Tesseract OCR, and system-level tools like Ghostscript and Poppler
- Development workflows incorporate Gradle, Docker, and multi-stage builds for scalable deployment
- Testing frameworks include Vitest, Jest, and Playwright for comprehensive end-to-end validation
Code Quality
The codebase reflects a mixed quality with some consistent practices and notable technical debt.
- A comprehensive testing approach covers various scenarios, though coverage remains limited in some areas
- Error handling is implemented through standard try/catch blocks with room for improvement in consistency
- Coding conventions are partially followed, with some duplication and lack of modularization in core components
- Linting and CI/CD pipelines are configured to support code quality standards
What Makes It Unique
This project stands out through its integration of powerful PDF processing with a modern UI and extensive tooling support.
- It uniquely combines Java-based PDFBox core functionality with a responsive web interface built on React and TypeScript
- The platform supports a wide array of document manipulation tools and system integrations for enhanced versatility
- Extensive configuration options allow customization for diverse deployment scenarios and use cases